Diagnosis

Typhlochactidae may be separated from all other scorpion families on the basis of the following combination of characters. Carapace, tergites, pedipalps, and metasoma not pigmented or infuscated. Cheliceral movable finger, external distal tooth smaller than internal distal tooth; ventral surface with serrula; ventral edge smooth, without teeth. Carapace without median or lateral ocelli; anterior margin without median notch (emargination). Pedipalp chela fingers, median denticle row comprising oblique, nonoverlapping primary subrows. Pedipalp patella, internal surface, dorsal and ventral processes absent or very weakly developed, comprising at most a low granule. Pedipalp femur trichobothrium e situated on dorsal surface or dorsoexternal carina; trichobothrium d situated proximal to or level with trichobothrium i. Pedipalp patella trichobothrium i situated on dorsal surface; ventral surface with two or three trichobothria. Pedipalp chela trichobothrium Db situated proximally; trichobothrium Dt situated distally. Legs without tibial spurs, retrolateral pedal spurs, and often without prolateral pedal spurs; basitarsi I–IV without retroventral or retrolateral rows of spinules or spinule clusters; III and IV without proventral rows of spinules or spinule clusters; telotarsi, laterodistal lobes truncate, each with two pairs of terminal macrosetae, usually without ventromedian row of spinules, and with somewhat irregular, paired ventrosubmedian rows of macrosetae. Sternum Type 2, pentagonal; apex rounded; lateral lobes flat; not longitudinally compressed. Pectinal lamellae fused to some degree; fulcra absent; teeth straight, nonoverlapping. Genital opercula (male), medial edges closely adpressed, genital papillae only visible at posterior edges or in posterior third; genital opercula (female), sclerites fused, usually loosely connected by membrane along entire length of suture. Respiratory spiracles (stigmata) small, rounded. Metasomal segments I–III, dorsosubmedian carinae, distal granules not noticeably larger than preceding granules; segment IV, dorsolateral carina termination conspicuously flared, straight. Telson without anterodorsal lateral lobes. Hemispermatophore lamelliform; capsule weakly developed; spiniform processes absent.

Included taxa

Comprising two subfamilies: Alacraninae, comprising one genus, Alacran 18Francke, 1982, monotypic; Typhlochactinae, comprising three genera, Sotanochactas Francke, 1986, monotypic, Stygochactas, new genus, monotypic, and Typhlochactas Mitchell, 1971, with six species (table 2).

Distribution

Endemic to Mexico. Recorded from five states: Oaxaca, Queretaro, San Luis Potosí, Tamaulipas, Veracruz (fig. 1).

TABLE 5

Discrete diagnostic characters separating the genera and species of Typhlochactidae Mitchell, 1971 (modified from Sissom and Cokendolpher, 1998)

Abbreviations as follows: A. tar.  =  Alacran tartarus 18Francke, 1982; S. ell.  =  Sotanochactas elliotti (Mitchell, 1971); S. gra.  =  Stygochactas granulosus (Sissom and Cokendolpher, 1998); T. cav.  =  Typhlochactas cavicola Francke, 1986; T. mit.  =  Typhlochactas mitchelli Sissom, 1988; T. red.  =  Typhlochactas reddelli Mitchell, 1968; T. rho.  =  Typhlochactas rhodesi Mitchell, 1968; T. sis.  =  Typhlochactas sissomi Francke et al., 2009; T. syl.  =  Typhlochactas sylvestris Mitchell and Peck, 1977; abs.  =  absent; pres.  =  present

Diagnosis

Alacraninae, the sister group of Typhlochactinae (fig. 4), may be separated from the latter on the basis of the following combination of characters. Size moderate to large, total length (adult), 60–70 mm. Cheliceral fixed finger, median and basal teeth not fused into a bicusp; movable finger with five dorsal teeth (two subdistal teeth present). Carapace, anterior margin, median projection (epistome) absent; median longitudinal sulcus obsolete. Pedipalp femur dorsoexternal, dorsointernal, and ventrointernal carinae, patella dorsoexternal, externomedian, ventroexternal, ventrointernal and internomedian carinae, and chela external secondary, ventroexternal and ventrointernal carinae, well developed. Pedipalp chela, fixed and movable fingers, median denticle row comprising six and seven oblique primary subrows, respectively; internal denticles smaller than external denticles; fixed finger, terminal denticle considerably larger than preceding denticles, hooklike, fingertips interlocking unevenly when closed. Pedipalp patella with 25–27 trichobothria, three situated on dorsal surface, 19–21 (including 6–8 accessory trichobothria) on external surface, and three on ventral surface. Chela with 29 trichobothria, 11 (including an accessory trichobothrium) situated on fixed finger and 18 (including one accessory trichobothrium on external surface and another on ventral surface) situated on manus. All trichobothrial areolae small, similar in diameter, trichobothrial setae similar in length (none “petite”). Chela fixed finger, dorsal and external trichobothria situated in distal half of finger. Leg basitarsi with prolateral pedal spurs, retrolateral surfaces without spinules distally; telotarsi each with more than 10 thin, acuminate macrosetae in paired ventrosubmedian rows, without ventromedian row of spinules. Sternite VII, ventrolateral carinae weakly developed. Metasomal segments I–IV, dorsosubmedian and ventrolateral carinae well developed; segment V, dorsolateral and ventrolateral carinae well developed. Telson (adult) vesicle markedly globose; aculeus very short.

Included taxa

Monotypic genus, Alacran 18Francke, 1982.

Distribution

Endemic to Mexico. Recorded from Oaxaca (fig. 1A).

Diagnosis

As for subfamily.

Included taxa

Single species, Alacran tartarus 18Francke, 1982.

Distribution

Specimens of Alacran have been collected from five caves in the state of Oaxaca, southeastern Mexico (Cueva de Escorpión, Sótano Agua de Carrizo, Sótano Li Nita, Sótano de San Agustin, Te Cimutaá Cave). Alacran tartarus is known from the first four of these caves which occur in the Sistema Huautla (Reddell, 1981), a large integrated karstic system of very deep caves on the Huautla Plateau (ca. 2000 m elevation) of the Sierra Mazateca, northern Oaxaca (fig. 1A). The fifth cave, Te Cimutaá, is a new record for the genus and may represent a new species.

Ecology

Alacran tartarus, an obligate troglobite, inhabits some of the deepest caves in the world (fig. 3C, D). This species has been collected at depths of 720–916 m below the surface (Francke, 1982a), the deepest records at which a scorpion has been found, and an order of magnitude greater than the next deepest record (−75 m) for a troglobitic scorpion, Sotanochactas elliotti from El Sótano de Yerbaniz (Francke, 1982a). The large size of Alacran (60–70 mm) is remarkable given the depths at which these scorpions live and the amounts of energy that must be transported there to support them (Francke, 1982a). Most species of Typhlochactinae follow the usual trend toward small size in troglobitic arthropods and are less than 25 mm in length. Alacran appears to be amphibious: the second specimen from Cueva de Escorpión was collected on a wet flowstone wall (fig. 3E, F) and the specimen from Te Cimutaá Cave was found underwater in a small stream (A.G. Gluesenkamp and P. Sprouse, personal commun.).

Fig. 5

Typhlochactidae Mitchell, 1971, chelicerae, dorsal aspect. A. Alacran tartarus 18Francke, 1982, paratype ♂ (AMNH). B. Sotanochactas elliotti (Mitchell, 1971), paratype ♂ (WDS). C. Stygochactas granulosus (Sissom and Cokendolpher, 1998), juv. ♂ holotype (AMNH). D. Typhlochactas cavicola Francke, 1986, holotype ♀ (AMNH). E. Typhlochactas mitchelli Sissom, 1988, holotype ♂ (AMNH). F. Typhlochactas reddelli Mitchell, 1968, holotype ♀ (AMNH). G. Typhlochactas rhodesi Mitchell, 1968, holotype ♀ (AMNH). H. Typhlochactas sissomi Francke et al., 2009, subad. ♂ holotype (IBUNAM), dextral chelicera. I. Typhlochactas sylvestris Mitchell and Peck, 1977, holotype ♀ (AMNH), sinistral chelicera. Scales: A  =  1 mm; B–H  =  0.1 mm.

Fig. 6

Typhlochactidae Mitchell, 1971, carapace, dorsal aspect. A. Alacran tartarus 18Francke, 1982, paratype ♂ (AMNH). B. Alacran tartarus 18Francke, 1982, ♀ (WDS). C. Sotanochactas elliotti (Mitchell, 1971), paratype ♂ (WDS). D. Stygochactas granulosus (Sissom and Cokendolpher, 1998), juv. ♂ holotype (AMNH). Scales: A, B  =  1 mm; C, D  =  0.5 mm.

Fig. 7

Typhlochactidae Mitchell, 1971, sternum, genital operculum and pectines, ventral aspect. A. Alacran tartarus 18Francke, 1982, ♀ (WDS). B. Sotanochactas elliotti (Mitchell, 1971), paratype ♂ (WDS). C. Typhlochactas rhodesi Mitchell, 1968, holotype ♀ (AMNH). Scales: A  =  1 mm; B, C  =  0.5 mm.

Fig. 8

Typhlochactidae Mitchell, 1971, sternum, genital operculum and pectines, ventral aspect. A. Stygochactas granulosus (Sissom and Cokendolpher, 1998), juv. ♂ holotype (AMNH). B. Typhlochactas mitchelli Sissom, 1988, holotype ♂ (AMNH). C. Typhlochactas cavicola Francke, 1986, holotype ♀ (AMNH). D. Typhlochactas sylvestris Mitchell and Peck, 1977, holotype ♀ (AMNH). Scales  =  0.5 mm.

Fig. 9

Typhlochactidae Mitchell, 1971, dextral pedipalp chela fixed (left) and movable (right) fingers, dentition patterns. A, B. Alacran tartarus 18Francke, 1982. C, D. Sotanochactas elliotti (Mitchell, 1971). E, F. Stygochactas granulosus (Sissom and Cokendolpher, 1998). G, H. Typhlochactas cavicola Francke, 1986. I, J. Typhlochactas mitchelli Sissom, 1988. K, L. Typhlochactas reddelli Mitchell, 1968. M, N. Typhlochactas rhodesi Mitchell, 1968. O, P. Typhlochactas sissomi Francke et al., 2009. Q, R. Typhlochactas sylvestris Mitchell and Peck, 1977.

Fig. 10

Typhlochactidae Mitchell, 1971, sinistral legs I–IV, basitarsi and telotarsi, retrolateral aspect. A–D. Alacran tartarus 18Francke, 1982, ♀ (WDS). E–H. Sotanochactas elliotti (Mitchell, 1971), paratype ♂ (WDS). I–L. Stygochactas granulosus (Sissom and Cokendolpher, 1998), juv. ♂ holotype (AMNH). Scales: A  =  0.1 mm; B, C  =  0.5 mm.

Fig. 11

Alacran tartarus 18Francke, 1982, paratype ♂ (AMNH), metasoma and telson, lateral aspect. Scale  =  5 mm.

Fig. 12

Typhlochactinae Mitchell, 1971, metasoma and telson, lateral aspect. A. Sotanochactas elliotti (Mitchell, 1971), paratype ♂ (WDS). B. Stygochactas granulosus (Sissom and Cokendolpher, 1998), juv. ♂ holotype (AMNH). C. Typhlochactas cavicola Francke, 1986, holotype ♀ (AMNH). D. Typhlochactas mitchelli Sissom, 1988, holotype ♂ (AMNH). E. Typhlochactas reddelli Mitchell, 1968, holotype ♀ (AMNH), segments IV, V and telson only. F. Typhlochactas rhodesi Mitchell, 1971, holotype ♀ (AMNH). G. Typhlochactas sylvestris Mitchell and Peck, 1977, holotype ♀ (AMNH). Scales  =  1 mm.

Fig. 13

Alacran tartarus 18Francke, 1982, ♀ (AMNH), habitus. A. Dorsal aspect. B. Ventral aspect. Scale  =  1 cm.

Fig. 14

Alacran tartarus 18Francke, 1982, juv. ♂ paratype (AMNH), habitus. A. Dorsal aspect. B. Ventral aspect. Scale  =  1 cm.

Fig. 15

Alacran tartarus 18Francke, 1982, sinistral pedipalp chela showing carinae and distribution of trichobothria. A. Paratype ♂ (AMNH). B–D. ♀ (WDS). A, C. External aspect. B. Dorsal aspect. D. Ventral aspect. Scales  =  1 mm.

Fig. 16

Alacran tartarus 18Francke, 1982, ♀ (WDS), sinistral pedipalp femur (A) and patella (B–D) showing carinae and distribution of trichobothria. A, B. Dorsal aspect. C. External aspect. D. Ventral aspect. Scales  =  1 mm.

TABLE 6

Meristic data for Alacran tartarus 18Francke, 1982

Measurements (mm) follow Francke et al. (2009). Abbreviations as follows: AMNH  =  American Museum of Natural History, New York; MNHN  =  Muséum National d'Histoire Naturelle, Paris; WDS  =  W. David Sissom Private Collection, Canyon, TX

Type material

Mexico: Oaxaca: Município de San Miguel: Holotype: 1 ♀ (AMNH), Sótano de San Agustín [18°06′23″N 96°47′53″W, −720 m], San Agustín, 5 km SE Huautla de Jiménez, 1979 San Agustín Expedition members of the Huautla Project, Spring 1979. Paratypes: 1 juv. ♂ (AMNH), same data as holotype; 1 ♂ (AMNH), Sótano Li Nita [18°08′51″N 96°47′56″W, −812 m], San Agustín, 5 km SE Huautla de Jiménez, B. Steele and S. Zeman, 1980 Río Iglesia Expedition, 29.III.1980; 1 juv. ♀ (AMNH), Sótano Agua de Carrizo [18°08′16″N 96°47′39″W, −760 m], 5 km ESE Huautla de Jiménez, A.G. Grubbs, B. Stone, J. Smith, T. Johnson and M. McEachern, 23.V.1978; 1 ♀ (MNHN), Cueva de Escorpión [18°06′23″N 96°47′53″W], San Miguel Dolina, 5 km SE Huautla de Jiménez, R. Jameson and P. Mothes, I.1978.

Diagnosis

As for subfamily.

Description

The following redescription supplements Francke's (1982a) original description. It is based on the holotype, three paratypes, and six additional specimens. Only two adult males and five adult females are known (table 2).

Color: Adult (fig. 13), carapace, pedipalp femur, tergites, metasomal segments, and telson, Amber (36) with darker carinae; pedipalp patella and chela, Kingfisher Rufous (240) to Mahogany Red (132B), fingers slightly darker; chelicerae, legs, and sternites, Buff (24); pectines, Chamois (123D); cheliceral teeth, aculeus dark. Subadult (fig. 14), Sulphur Yellow (57) to Cream (54); aculeus and telotarsal ungues dark, Chestnut (32).

Chelicerae: Manus, dorsal and ventral surfaces smooth; dorsal surface with two microsetae; ventral surface with short brushlike macrosetae becoming longer on fixed finger. Fixed finger with four teeth (distal, subdistal, median and basal); median and basal teeth not fused into bicusp; distal tooth largest, subdistal and median teeth equal, smaller, basal tooth smallest. Movable finger, internal distal and external distal teeth opposable, internal distal tooth completely overlapping external distal tooth in dorsal view; dorsal margin with five teeth (internal distal, two subdistal, median and basal; fig. 5A), internal distal tooth largest, subdistal and median teeth equal, smaller, basal tooth smallest; ventral surface with serrula, extending less than half length of finger, completely covered by long, dense macrosetae.

Carapace: Length slightly greater than anterior width (table 6). Anterior margin sublinear, without median projection (epistome); with 6–8 microsetae (fig. 6A, B). Posterior margin concave; asetose. Median and lateral ocelli absent. Median longitudinal sulcus obsolete; posterolateral sulci shallow; posterior transverse sulcus deep. Surface acarinate, with scattered subspiniform granules.

Pedipalps: Femur dorsoexternal, dorsointernal, ventrointernal, ventroexternal carinae distinct, comprising discontinuous rounded to spiniform granules (fig. 16A); ventroexternal carina less developed, comprising fewer granules, of similar dimensions. Dorsal surface smooth, with few granules medially; external surface granular; ventral surface with few granules proximally and small row of granules distally; internal surface smooth. Patella dorsoexternal, dorsointernal, ventroexternal, and ventrointernal carinae distinct, granular; internomedian carina comprising well-developed granular row; externomedian carinae obsolete (fig. 16B–D). Dorsal surface slightly concave and smooth except for two small granular areas surrounding trichobothria d₂ and i; external surface with several large granules, close to trichobothria; ventral surface smooth. Chela long, with relatively large, swollen manus (fig. 15). Dorsomedian, dorsal secondary, digital, ventroexternal, ventromedian and ventrointernal carinae distinct, similar, each comprising row of granules; external secondary carina distinct but weaker, comprising fewer, smaller granules; internomedian and dorsointernal carinae comprising few isolated granules between ventromedian and dorsomedian carinae. Manus, intercarinal surfaces smooth; internal surface with prominent, isolated granule near movable finger condyle and row of prominent, isolated granules from base of movable finger to base of fixed finger; fixed finger smooth. Fixed and movable fingers, median denticle row comprising six (occasionally five) and seven (occasionally six) oblique primary subrows, respectively (fig. 9A, B); internal denticles smaller than external denticles; fixed finger, terminal denticle considerably larger than preceding denticles, hooklike, fingertips interlocking unevenly when closed.

Trichobothria: Femur with three trichobothria (fig. 16A): one external (e), one dorsal (d), one internal (i). Patella with 26 or 27 trichobothria (fig. 16B–D), eight accessory (et_a1, et_a2, est_a, em₃, em_a1, em_a2, esb_a1, esb_a2): three ventral (v₁–v₃); 21 (rarely 19 or 20) external (et₁–et₃, et_a1, et_a2, est, est_a, em₁–em₃, em_a1, em_a2, esb₁, esb₂, esb_a1, esb_a2, eb₁–eb₅); two dorsal (d₁, d₂); one internal (i). Chela with 29 trichobothria (fig. 15), three accessory (V_a, em, Em, V_a): 18 on manus, five ventral (V₁–V₄, V_a), 11 external (Et₁–Et₅, Est, Esb, Em, Eb₁–Eb₃), two dorsal (Db, Dt); 11 on fixed finger, five external (et, est, em, esb, eb), four dorsal (dt, dst, dsb, db), two internal (it, ib). All trichobothrial areolae small, similar in diameter, trichobothrial setae similar in length (none “petite”).

Legs: Femur and patella elongated, similar in length. Femur laterally compressed; unicarinate; dorsal and ventral surfaces separated by row of distinct granules; surfaces with few macrosetae. Patella less compressed than femur; dorsal surface smooth; ventral edge granular; surfaces sparsely setose. Basitarsi prolateral, retrolateral and proventral surfaces with macrosetae, similar in number on I–III, fewer on IV; I–IV, each with large prolateral pedal spur (fig. 10A–D); I and II, proventral surface without spinules. Telotarsi, dorsomedian lobe with one large microseta; ventral surface without spinules and with at least 10 ventrosubmedian pairs of thin, acuminate macrosetae; ungues well developed, curved, equal in length; dactyl large, prominent.

Tergites: Pretergites, surfaces smooth. Posttergites I–V, surfaces smooth; VI and VII, surfaces with scattered granules posteriorly; VII, lateral margins with small spiniform granules in distal three-quarters, large sparse granules medially; I–VI, acarinate; VII, dorsosubmedian carinae vestigial, reduced to few posterior granules, dorsolateral carinae distinct, complete (fig. 13A).

Sternum: Posterior width greater than length (fig. 7A); apex rounded; lateral margins converging anteriorly; lateral lobes flat; posterior depression shallow. Surface with two macrosetae and several microsetae.

Genital operculum: Sclerites (♂) completely divided; genital papillae protruding distinctly beyond posterior edges. Sclerites (♀) fused, but loosely connected by membrane along entire length of suture (fig. 7A). Surfaces covered by microsetae.

Pectines: Pectinal plate, surface with several macrosetae. Lamella comprising four segments (fig. 7A); surfaces with four macrosetae and several microsetae. Tooth count, 5/5–6 (♂), 5/5 (♀); teeth elongated, similar in dimensions; proximal and distal teeth slightly larger; surfaces covered with microsetae.

Sternites: Anterior and posterior margins straight (posterior margin of sternite III concave in one female; fig. 13B), with few macrosetae; III and IV, surfaces almost smooth, lateral and posterior margins with very small granules; V and VI, surfaces with few granules; VII, surfaces with more granules, especially in distal half, and with pair of weakly developed ventrolateral carinae. Respiratory spiracles (stigmata) small, round, situated posterolaterally (fig. 7A).

Metasoma: Segments elongated, length greater than width (fig. 11), progressively increasing in length, decreasing in width (table 6); segment V longer than carapace. Dorsosubmedian carinae, segments I–IV, distinct, granular, distal granules not noticeably larger than preceding granules; V, absent. Dorsolateral carinae, segments I–III, obsolete, composed of sparsely distributed granules; IV, absent; V, distinct, granular. Median lateral carinae, segments I and II, distinct, granular, incomplete; III–V, absent. Ventrolateral carinae, segments I–V, distinct, granular, complete. Ventrosubmedian carinae, segments I–IV, and ventromedian carina, segment V, absent. Anal arch smooth dorsally, granular and setose ventrally. Intercarinal surfaces smooth except dorsal surfaces, segments IV and V, sparsely granular. Lateral and ventral intercarinal surfaces with few microsetae, increasing in number from segments I–V.

Telson: Vesicle globose, especially in adults, slightly compressed laterally; anterodorsal lateral lobes absent (fig. 11); surface smooth with few, small granules along anterodorsal margin; few short macrosetae anteriorly; short microsetae ventrally and near base of aculeus. Aculeus very short, arising abruptly from vesicle, slightly curved.

Hemispermatophore: Lamelliform, basal portion narrow; capsular region with large, sclerotized lobe; spiniform processes absent. See Francke (1982a: 58) for illustrations.

Ontogenetic variation: Subadults and juveniles (fig. 14) differ from adults (fig. 13) as follows. Coloration of subadult and juvenile paler than adult: yellowish cream with aculeus, extremity of leg ungues, pedipalp chela denticle rows and cheliceral teeth brownish. Carapace, anterior margin with well-developed median projection (epistome) in juvenile, weakly developed to absent in adult. Pedipalp and metasomal carination largely absent in juvenile, weakly developed in subadult, well developed in adult. Surface granulation less developed in subadult and juvenile. Telson of subadult and juvenile more setose, less globose (ratio of vesicle height : length 150% in juvenile, 100–122% in subadult, 76–112% in adult), with longer aculeus (table 6).

Sexual dimorphism: Adult male similar to adult female in most respects, except for slightly more pronounced carination and granulation (fig. 6A, B), completely divided genital operculum, presence of genital papillae and slightly larger pectinal teeth.

Geographical variation: Little variation among specimens from the Sistema Huautla.

Remarks

The female paratype was listed by Francke (1982a: 55) as deposited in the author's collection and by Fet and Sissom (2000) as deposited in the AMNH collection. The paratype is actually deposited in the MNHN.

A large, sinistral pedipalp chela, collected together with the holotype of Stygochactas granulosus from Sótano de Poncho in the neighboring state of Veracruz, is conspecific with the latter species and not with Alacran tartarus, with which it was compared by Sissom and Cokendolpher (1998: 289). See remarks to S. granulosus for details.

Distribution

Specimens of A. tartarus have been collected from four caves of the Sistema Huautla (figs. 1A, 3C–F) in the state of Oaxaca, southeastern Mexico (Cueva de Escorpión, Sótano Agua de Carrizo, Sótano Li Nita, Sótano de San Agustín).

Ecology

As for genus.

Additional material

Mexico: Oaxaca: Município de San Miguel: 2 ♀ (WDS), Sótano de San Agustín [18°06′23″N 96°47′53″W, −720 m] Section, Sistema Huautla, A.G. Grubbs, J.H. Smith and F. Holliday, V.1985; 1 juv. ♀ (AMNH), Sótano Li Nita [18°08′51″N 96°47′56″W], San Agustín, 5 km SE Huautla de Jiménez, White Room Lead, −871 m, M. Minton, 22.III.1981; 1 ♀ (AMNH), Sótano Li Nita [18°08′51″N 96°47′56″W], −916 m, San Agustín, 5 km SE Huautla de Jiménez, M. Minton, L. Wilk and R. Simmons, 1.IV.1981; 1 ♂ (AMNH), leg (AMCC [LP 3499]), Cueva de Escorpión, 18°06′23″N 96°47′53″W, 1561 m, A. Gluesenkamp, P. Sprouse and C. Savvas, 18.IX.2004.

Remarks

A single female specimen recently collected in Te Cimutaá Cave (fig. 1A) may be an undescribed species. The specimen has a different number of primary subrows in the median denticle row of the pedipalp chela fingers, a proportionally shorter metasoma, and is less granular, with slightly weaker carinae, than specimens of A. tartarus from the Sistema Huautla.

Material examined

Mexico: Oaxaca: Município de Valle Nacional: 1 ♀ (IBUNAM), leg (AMCC [LP 8571]), Te Cimutaá Cave, 17°54′19″N 96°22′39″W, 944 m, P. Bryant, 25.IV.2008.

Diagnosis

Typhlochactinae, the sister group of Alacraninae (fig. 4), may be separated from the latter on the basis of the following combination of characters. Size usually small to very small, total length (adult) less than 25 mm. Cheliceral fixed finger, median and basal teeth usually not fused into a bicusp; movable finger with three, four, or five dorsal teeth (none, one, or two subdistal teeth). Carapace, anterior margin, median projection (epistome) usually present; median longitudinal sulcus well developed. Pedipalp femur dorsoexternal, dorsointernal, and ventrointernal carinae, patella dorsoexternal, externomedian, ventroexternal, and ventrointernal carinae, and chela external secondary, ventroexternal and ventrointernal carinae, usually absent or obsolete. Pedipalp chela, fixed and movable fingers, median denticle row comprising 4–7 and 5–7 oblique primary subrows, respectively; internal denticles larger than external denticles. Pedipalp patella with 19 (rarely 20) trichobothria, three situated on dorsal surface, 14 (rarely 15), including one (rarely two) accessory trichobothria, on external surface, and two on ventral surface. Chela with 26 trichobothria, 10 situated on fixed finger and 16 situated on manus. Twelve (rarely 13) trichobothria with areolae noticeably smaller and setae noticeably shorter than the others (“petite”): five (rarely six) on patella (d₁, d₂, et₂, esb₂, eb₂, v₃), seven on chela (Db, Esb, Et₄, Et₅, V₁, db, esb). Leg basitarsi often without prolateral pedal spurs, retrolateral surfaces with short row of tiny spinules distally; telotarsi each with 3–8 subspiniform macrosetae in paired ventrosubmedian rows, usually without ventromedian row of spinules. Sternite VII, ventrolateral carinae absent. Metasomal segments I–IV, dorsosubmedian and ventrolateral carinae usually absent or obsolete; segment V, dorsolateral carinae and, usually, ventrolateral carinae absent or obsolete. Telson (adult) vesicle unmodified to globose; aculeus short to moderate in length.

Included taxa

Three genera: Sotanochactas Francke, 1986, monotypic; Stygochactas, new genus, monotypic; Typhlochactas Mitchell, 1971, with six species (table 2).

Distribution

Endemic to Mexico. Recorded from five states: Oaxaca, Queretaro, San Luis Potosí, Tamaulipas, Veracruz (fig. 1B).

Ecology

Sotanochactas, Stygochactas, and three species of Typhlochactas are troglobitic (hypogean). The other three species of Typhlochactas, T. mitchelli, T. sissomi, and T. sylvestris, are humicolous (endogean) (Mitchell and Peck, 1977; Sissom, 1988; Francke et al., 2009; table 2). The three endogean species are also markedly troglomorphic, however. It is possible that they may inhabit caves, on occasion. A similar ecology was described for Belisarius xambeui, a troglomorphic scorpion from the Pyrenees of France and Spain, and other cave-adapted arthropods, e.g., beetles and crickets (Auber, 1959; Peck and Thayer, 2003; Sbordoni et al., 2004), which have been collected in leaf litter and also in caves.

Diagnosis

Sotanochactas is the sister taxon of a monophyletic group comprising Stygochactas and Typhlochactas (fig. 4), from which it may be separated on the basis of the following combination of characters. Size small, total length (adult) less than 25 mm. Cheliceral fixed finger with four teeth (subdistal present); median and basal teeth not fused into a bicusp; movable finger with four dorsal teeth (one subdistal present). Carapace, anterior margin, median projection (epistome) present. Pedipalps greatly elongated, chela fingers twice as long as manus. Pedipalp femur, ventroexternal carina, and patella, internomedian carina, distinct. Pedipalp chela, dorsal secondary, digital, ventroexternal, ventromedian, and ventrointernal carinae absent or obsolete. Chela fixed and movable fingers, median denticle rows comprising six and five oblique primary subrows, respectively; basal primary subrows considerably longer than other subrows; terminal denticle of fixed finger slightly larger than preceding denticles, fingertips interlocking evenly when closed. Patella trichobothrium v₁ situated distal to trichobothrium esb₁. Chela fixed finger, external trichobothria situated in distal half of finger, trichobothrium eb situated midway on finger; trichobothrium it situated midway along finger; trichobothrium ib situated midway in proximal third of finger. Legs without prolateral pedal spurs. Basitarsi I and II, proventral surfaces with short row of closely aligned spinules subdistally. Telotarsi, ventral surface without ventromedian row of spinules. Sclerites of genital operculum (♀) fused, but loosely connected by membrane along entire length of suture. Tergite VII, dorsolateral carinae distinct, complete. Metasomal segments I–IV, dorsosubmedian carinae distinct; I–III, dorsolateral carinae distinct; I, median lateral carinae obsolete, incomplete; I–V, ventrolateral carinae obsolete (I) to distinct (II–V); V, ventromedian carina obsolete.

Included taxa

Monotypic genus: Sotanochactas elliotti (Mitchell, 1971).

Distribution

Endemic to Mexico. Recorded from San Luis Potosí.

Fig. 17

Sotanochactas elliotti (Mitchell, 1971), paratype ♂ (WDS), habitus. A. Dorsal aspect. B. Ventral aspect. Scale  =  1 mm.

Fig. 18

Sotanochactas elliotti (Mitchell, 1971), paratype ♂ (WDS), sinistral pedipalp chela showing carinae and distribution of trichobothria. A. Dorsal aspect. B. External aspect. C. Ventral aspect. Scale  =  0.5 mm.

Fig. 19

Sotanochactas elliotti (Mitchell, 1971), paratype ♂ (WDS), sinistral pedipalp femur (A) and patella (B–D) showing carinae and distribution of trichobothria. A, B. Dorsal aspect. C. External aspect. D. Ventral aspect. Scales  =  0.5 mm.

TABLE 7

Meristic data for Sotanochactas elliotti (Mitchell, 1971), Stygochactas granulosus (Sissom and Cokendolpher, 1998) and Typhlochactas sissomi Francke et al., 2009

Measurements (mm) follow Francke et al. (2009). Abbreviations as follows: AMNH  =  American Museum of Natural History, New York; IBUNAM  =  Instituto de Biología, Universidad Nacional Autonóma de México, Mexico City; MNHN  =  Muséum National d'Histoire Naturelle, Paris; WDS  =  W. David Sissom Private Collection, Canyon, TX

Type material

Mexico: San Luis Potosí: Município de Ciudad Valles: Holotype: 1 subad. ♂ (AMNH), El Sótano de Yerbaniz, 21 km N Ciudad Valles, Sierra de El Abra [22°11′07″N 98°59′12″W], ca. 250 m, W.R. Elliott, 31.VII.1969. Paratypes: 1 juv. ♀ (MNHN RS 5376), same locality, W.R. Elliott, 27.III.1970; 1 ♂ (WDS), same locality, R.W. Mitchell, 4.VII.1970.

Diagnosis

As for genus.

Description

Mitchell (1971: 144) listed a holotype and two paratypes: a possible immature female (MNHN), marked with a questionmark, and another specimen, alive when the paper was published and the sex of which was given as undetermined, but which was, in fact, an adult male. Mitchell's (1971) description was based on the subadult male holotype. Francke (1982a) subsequently illustrated the hemispermatophore of the adult male paratype. We present the first description of the adult male (fig. 17), supplementing Mitchell's (1971) original description of the subadult male and Francke's (1982a) description of the hemispermatophore.

Color: Mitchell (1971) described the living specimens as almost transparent and lacking pigmentation. Coloration of preserved specimens as follows (fig. 17). Holotype, uniformly Cinnamon (123A). Paratype ♂ (WDS), chelicerae, carapace and pedipalps, Chamois (123D); mesosoma and metasoma, Clay (123B); legs, Cream (54); telson similar to but slightly darker than legs; cheliceral teeth, pedipalp finger denticle rows, leg ungues and dactyl, and aculeus, reddish.

Chelicerae: Manus, dorsal and ventral surfaces smooth; dorsal surface with several microsetae, two larger microsetae situated near base of fixed finger; movable finger, dorsal surface with six microsetae. Fixed finger, dorsal margin with four teeth (distal, subdistal, median, and basal; fig. 5B); median and basal teeth not fused into bicusp; distal tooth largest, subdistal and median teeth equal, smaller, basal tooth smallest. Movable finger, internal distal and external distal teeth opposable, internal distal tooth completely overlapping external distal tooth in dorsal view; dorsal margin with four teeth (internal distal, subdistal, median, and basal), internal distal tooth largest, subdistal and median teeth equal, smaller, basal tooth smallest; ventral surface with long serrula, extending distal three-quarters of finger, tines increasing in size distally, covered by dense brush of macrosetae.

Carapace: Length considerably greater than anterior width (table 7). Anterior margin weakly convex, with small median projection (epistome) (fig. 6C). Posterior margin convex; asetose. Median and lateral ocelli absent. Median longitudinal sulcus well developed; posterolateral sulci obsolete; posterior transverse sulcus deep. Surface acarinate, uniformly finely granular, especially along median longitudinal sulcus. Surface and margins with several microsetae.

Pedipalps: Pedipalps greatly elongated, slender (figs. 18, 19). Femur, ventroexternal carina distinct, granular, other carinae obsolete (fig. 19A). Dorsal surface with scattered granules on proximal three-quarters, becoming smooth distally; external and internal surfaces smooth; ventral surface granular proximally, becoming smooth distally. Dorsal, external, and internal surfaces each with several long microsetae; ventral surface asetose. Patella, dorsointernal carina distinct, granular; dorsoexternal, ventroexternal, and ventrointernal carinae obsolete; internomedian carina comprising row of granules; externomedian carinae absent (fig. 19B–D). Dorsal and external surfaces smooth; internal surface with scattered granules and long microsetae. Chela fingers very elongated, movable finger longer than carapace, more than twice length along ventroexternal carina (table 7); manus width greater than or equal to height. Dorsal secondary, digital, external secondary, and ventrointernal carinae absent; ventroexternal and ventromedian carinae obsolete; other carinae absent (fig. 18). Chela manus, intercarinal surfaces smooth except for few small round granules on dorsal surface near base of fixed finger; internal surface with few granules except for prominent, isolated granule near movable finger condyle; fixed finger smooth. Manus and fingers, internal surfaces with several microsetae, often associated with median denticle row. Fixed finger, median denticle row comprising six oblique primary subrows, basal subrow very long (fig. 9C); internal denticles larger than external denticles, large internal denticle present between terminal and subterminal subrows, other four internal denticles smaller; terminal denticle of fixed finger slightly larger than preceding denticles, fingertips interlocking evenly when closed. Movable finger, median denticle row comprising five oblique primary subrows, basal subrow very long (fig. 9D).

Trichobothria: Femur with three trichobothria (fig. 19A): one external (e), one dorsal (d), one internal (i). Patella with 19 trichobothria (fig. 19B–D), five petite (d₁, d₂, et₂, esb₂, eb₂), one accessory (em₃): two ventral (v₁, v₂); 14 external (et₁–et₃, est, em₁–em₃, esb₁, esb₂, eb₁–eb₅); two dorsal (d₁, d₂); one internal (i). Chela with 26 trichobothria (fig. 18), seven petite (V₁, Et₄, Et₅, Esb, Db, esb, db): 16 on manus, four ventral (V₁–V₄), 10 external (Et₁–Et₅, Est, Esb, Eb₁–Eb₃), two dorsal (Db, Dt); 10 on fixed finger, four external (et, est, esb, eb), four dorsal (dt, dst, dsb, db), two internal (it, ib).

Legs: All segments smooth except for femur ventral surface, covered by stout granules increasing in size and density from legs I–IV. Dorsal and ventral surfaces with few short microsetae; basitarsi sparsely setose, setae more numerous on legs I and II. Basitarsi I–IV without prolateral pedal spurs (fig. 10E–H); I and II, proventral surface with short subdistal row of closely aligned spinules. Telotarsi, dorsomedian lobe with one large microseta; ventral surface without spinules, and with six submedian pairs of subspiniform macrosetae; ungues well developed, curved, equal in length; dactyl four times shorter than ungues.

Tergites: Pretergites, surfaces smooth. Posttergites with few microsetae, especially on posterior and lateral margins, granulation and setation increasing posteriorly; I–VI acarinate, surfaces finely granular; VII with small depression posteromedially, lateral and dorsolateral surfaces granular, more pronounced than on preceding tergites, dorsosubmedian carinae vestigial, reduced to few posterior granules, dorsolateral carinae distinct, complete (fig. 17A).

Sternum: Length greater than posterior width (fig. 7B); apex rounded; lateral margins converging anteriorly; lateral lobes flat; posterior depression shallow. Surface with eight macrosetae and several scattered microsetae.

Genital operculum: Sclerites (♂) completely divided; genital papillae protruding distinctly beyond posterior edges (fig. 7B). Sclerites (♀) fused, but loosely connected by membrane along entire length of suture.

Pectines: Pectinal plate, surface with two macrosetae situated mediolaterally. Lamella comprising three segments (fig. 7B), demarcated by very faint sutures; surfaces with few setae. Tooth count, 4–5/4–5; teeth elongated; proximal and distal teeth slightly larger.

Sternites: Posterior margin III, slightly concave (holotype) or sublinear, of other sternites convex. Surfaces acarinate (fig. 17B), smooth; VI and VII, lateral margins with small granules; VII, surface and posterior margin with microsetae. Respiratory spiracles (stigmata) small, round, situated posterolaterally.

Metasoma: Segments elongated, length greater than width (fig. 12A), progressively increasing in length, decreasing in width (table 7); segment V equal to or longer than carapace. Dorsosubmedian carinae, segments I–IV, distinct, granular, distal granules not noticeably larger than preceding granules; V, absent. Dorsolateral carinae, segment I, obsolete, granular, complete; II and III, obsolete, granular, incomplete; IV, absent; V, obsolete, granular. Median lateral carinae, segment I, distinct, granular, incomplete; II–V, absent. Ventrolateral carinae, segment I, obsolete, granular; II–V, distinct, composed of small, stout granules, complete. Ventrosubmedian carinae, segments I–IV, absent. Ventromedian carina, segment V, distinct, granular in anterior half of segment, becoming obsolete, sparsely granular posteriorly. Dorsal intercarinal surfaces, segments I–IV, slightly concave; V, convex. Intercarinal surfaces smooth except segment I, with few large granules. Dorsolateral carinae and lateral intercarinal surfaces with long microsetae; ventral intercarinal surfaces with at least three paired macrosetae.

Telson: Vesicle elongated, width equal to height (table 7), flattened dorsally, rounded ventrally; anterodorsal lateral lobes absent (fig. 12A); surface smooth, almost entirely covered in long macrosetae, except medially on dorsal surface. Aculeus long, moderately sclerotized, gently curved.

Hemispermatophore: Lamelliform; broad trunk, with long narrow prominence, originating in capsular region, bearing small, strongly sclerotized lobe; spiniform processes absent. See Francke (1982a: 58) for illustrations.

Ontogenetic variation: Subadult and juvenile paratypes completely whitish, ungues and cheliceral teeth only slightly darker at extremities, aculeus light reddish. Pedipalp and metasomal carinae less pronounced; all surfaces smooth.

Sexual dimorphism: Adult female unknown. Males exhibit completely divided genital operculum and genital papillae.

Geographical variation: All specimens from same locality.

Remarks

The juvenile ♀ paratype (MNHN) is damaged. The metasoma is broken, and the left pedipalp, legs I, II, and IV, are lost.

Distribution

Known only from the type locality, El Sótano de Yerbaniz, a vertical cave in the Sierra de El Abra karstic region, San Luis Potosí, central Mexico (figs. 1B, 2C–F).

Ecology

According to the original description, the holotype and one paratype of this troglobitic species were collected within 1 or 2 m of one another in a small, wet limestone tunnel about 75 m below the cave entrance (Mitchell, 1971). No data were provided for the third specimen, except that it was collected in the same cave. This species is considered the most troglomorphic member of the family, on account of the pronounced attenuation of its pedipalps (Francke, 1982a).

Diagnosis

Stygochactas is the sister taxon of Typhlochactas (fig. 4). It may be separated from Typhlochactas and Sotanochactas on the basis of the following combination of characters. Size moderate to large, total length of adult estimated (from single pedipalp chela) to be 60–70 mm. Cheliceral fixed finger with four teeth (subdistal present); median and basal teeth fused into a bicusp. Cheliceral movable finger with four dorsal teeth (one subdistal present). Carapace, anterior margin, median projection (epistome) obsolete. Pedipalps moderately elongated, chela fingers slightly longer than manus. Pedipalp femur, ventroexternal carina and patella, internomedian carina absent. Pedipalp chela, dorsal secondary, digital, ventroexternal, ventromedian, and ventrointernal carinae distinct. Chela fixed and movable fingers, median denticle rows of each comprising seven oblique primary subrows; basal primary subrows similar in length to other subrows; terminal denticle of fixed finger considerably larger than preceding denticles, hooklike, fingertips interlocking unevenly when closed. Patella trichobothrium v₁ situated level with trichobothrium esb₁. Chela fixed finger, external trichobothria distributed across entire length of finger, with trichobothrium eb situated near base of finger; trichobothria it and ib situated near base of finger. Legs without prolateral pedal spurs. Basitarsi I and II, proventral surfaces without short row of closely aligned spinules subdistally. Telotarsi, ventral surface, with curved proximal row spinules; without ventromedian row of spinules. Tergite VII, dorsolateral carinae absent or vestigial. Metasomal segments I–IV, dorsosubmedian carinae obsolete; I–III, dorsolateral carinae distinct; I, median lateral carinae absent; I–V, ventrolateral carinae absent or obsolete; V, ventromedian carina absent.

Included taxa

Monotypic genus: Stygochactas granulosus (Sissom and Cokendolpher, 1998).

Distribution

Endemic to Mexico. Recorded from Veracruz.

Fig. 20

Stygochactas granulosus (Sissom and Cokendolpher, 1998), juv. ♂ holotype (AMNH), habitus. A. Dorsal aspect. B. Ventral aspect. Scale  =  1 mm.

Fig. 21

Stygochactas granulosus (Sissom and Cokendolpher, 1998), juv. ♂ holotype (AMNH), sinistral pedipalp chela showing carinae and distribution of trichobothria. A. Dorsal aspect. B. External aspect. C. Ventral aspect. Scale  =  0.5 mm.

Fig. 22

Stygochactas granulosus (Sissom and Cokendolpher, 1998), juv. ♂ holotype (AMNH), sinistral pedipalp femur (A) and patella (B–D) showing carinae and distribution of trichobothria. A, B. Dorsal aspect. C. External aspect. D. Ventral aspect. Scales  =  0.5 mm.

Type material

Mexico: Veracruz: Município Tlaquilpa: Holotype: 1 juv. ♂ (AMNH), Sótano de Poncho [18°37′N 97°07′W, −73 m], P. Sprouse, 22.III.1995.

Diagnosis

As for genus.

Description

The following redescription supplements the original description of the holotype (fig. 20) by Sissom and Cokendolpher (1998).

Color: Chelicerae, carapace, legs, tergites, sternites, metasoma uniformly Cream (54); pedipalp chela Buff Yellow (53). Cheliceral teeth paler; pedipalp chela manus and denticle rows of fingers darker; ungues similar in color to telotarsi, but slightly darker distally (fig. 20).

Chelicerae: Manus, dorsal and ventral surfaces smooth; dorsal surface with four microsetae situated near base of fixed finger; movable finger with few microsetae. Fixed finger, dorsal margin with four teeth (distal, subdistal, median, and basal; fig. 5C); distal tooth largest, median and basal teeth equal, fused into bicusp. Movable finger, internal distal and external distal teeth opposable, internal distal tooth completely overlapping external distal tooth in dorsal view; dorsal margin with four teeth (internal distal, subdistal, median, and basal), internal distal tooth largest, subdistal and median teeth equal, smaller, basal tooth smallest; ventral surface with serrula along distal half of finger, comprising relatively large tines, partially covered by dense brush of macrosetae.

Carapace: Length similar to anterior width (table 7). Anterior margin sublinear, with small median projection (epistome) and six macrosetae (fig. 6D). Posterior margin sublinear; asetose. Median and lateral ocelli absent. Median longitudinal sulcus present, shallow; posterolateral sulci shallow; posterior transverse sulcus deep. Surface acarinate, uniformly finely granular, especially on posterolateral surfaces. Surface and margins with several microsetae.

Pedipalps: Pedipalps moderately elongated (figs. 21, 22). Femur, dorsoexternal, dorsointernal, ventrointernal, ventroexternal carinae obsolete, granular (fig. 22A). Dorsal, external, and internal surfaces with scattered granules; ventral surfaces smooth. Patella dorsoexternal carina distinct, granular; dorsoexternal, ventroexternal, and ventrointernal carinae obsolete; internomedian carina absent or vestigial, comprising at most one or two granules besides dorsal process; externomedian carinae absent (fig. 22B–D). Intercarinal surfaces less granular than femur; dorsal surfaces smooth; external surfaces with few larger granules distally; internal surface uniformly finely granular, with few larger granules proximally; ventral surfaces smooth. Chela manus slightly swollen, fingers longer than manus (fig. 21). Dorsal secondary, digital, ventroexternal, ventromedian, and ventrointernal carinae distinct, composed of similar, rounded granules; external secondary carina obsolete; other carinae absent. Manus, intercarinal surfaces smooth; internal surface with prominent, isolated granule near movable finger condyle and pair of prominent, isolated granules situated close together at base of fixed finger; fixed finger, proximal half granular dorsally. Manus and fingers covered by macrosetae; several extremely long macrosetae situated terminally on fingers. Fixed finger, median denticle row comprising seven oblique primary subrows of denticles, similar in length except for basal subrow, which is shorter (fig. 9E); internal denticles larger than external denticles; terminal denticle of fixed finger considerably larger than preceding denticles, hooklike, fingertips interlocking unevenly when closed. Movable finger, median denticle row comprising seven oblique primary subrows of denticles, terminal and proximal subrows shortest (fig. 9F); terminal denticle enlarged.

Trichobothria: Femur with three trichobothria (fig. 22A): one external (e), one dorsal (d), one internal (i). Patella with 19 trichobothria (fig. 22B–D), five petite (d₁, d₂, et₂, esb₂, eb₂), one accessory (em₃): two ventral (v₁, v₂); 14 external (et₁–et₃, est, em₁–em₃, esb₁, esb₂, eb₁–eb₅); two dorsal (d₁, d₂); one internal (i). Chela with 26 trichobothria (fig. 21), seven petite (V₁, Et₄, Et₅, Esb, Db, esb, db): 16 on manus, four ventral (V₁–V₄), 10 external (Et₁–Et₅, Est, Esb, Eb₁–Eb₃), two dorsal (Db, Dt); 10 on fixed finger, four external (et, est, esb, eb), four dorsal (dt, dst, dsb, db), two internal (it, ib).

Legs: Femur and patella II–IV, ventral surfaces, sparsely granular; basitarsi each with two rows of long macrosetae. Basitarsi I–IV without prolateral pedal spurs; I and II, proventral surface without spinules. Telotarsi, dorsomedian lobe with one microseta; ventral surface with curved row of spinules, proximally, and four or five submedian pairs of subspiniform macrosetae (fig. 10I–L); ungues long, curved, equal in length; dactyl short, robust.

Tergites: Pretergites, surfaces smooth. Posttergites, surfaces densely and finely granular, more so on VII, with scattered microsetae and pair of macrosetae submedially on posterior margins; I–VI, acarinate, VII, dorsosubmedian and dorsolateral carinae vestigial, reduced to few posterior granules (fig. 20A).

Sternum: Posterior width greater than length (fig. 8A); apex slightly rounded; lateral margins converging anteriorly; lateral lobes flat; posterior depression shallow. Surface with two pairs of macrosetae and several microsetae.

Genital operculum: Sclerites completely divided, strongly rounded posteriorly, each with single macroseta situated medially; genital papillae protruding distinctly beyond posterior edges (fig. 8A).

Pectines: Pectinal plate, surface with pair of macrosetae. Lamella comprising three segments (fig. 8A), demarcated by very faint sutures; surfaces with several macrosetae and numerous microsetae. Tooth count: 5/4; distal tooth larger, broader.

Sternites: Surfaces and margins smooth, acarinate (fig. 20B), with scattered microsetae; VII with several macrosetae. Respiratory spiracles (stigmata) small, round, situated posterolaterally.

Metasoma: Segments elongated, length greater than width (fig. 12B), progressively increasing in length, decreasing in width (table 7); segment V much longer than carapace. Dorsosubmedian carinae, segments I–IV, obsolete, granular, distal granules not noticeably larger than preceding granules (fig. 12B); V, absent. Dorsolateral and ventrolateral carinae, segment V, obsolete, granular, complete. Dorsolateral, median lateral, ventrolateral and ventrosubmedian carinae, segments I–IV, and ventromedian carina, segment V, absent. Dorsal intercarinal surfaces, segments I–IV, slightly concave; V, convex. Dorsal and ventral intercarinal surfaces sparsely granular, especially posteriorly; lateral intercarinal surfaces smooth. All segments with several macrosetae, especially on ventral surfaces.

Telson: Vesicle broad, elongated, flattened dorsally, rounded ventrally; anterodorsal lateral lobes absent (fig. 12B); surface smooth, with scattered long macrosetae. Aculeus short, weakly curved, arising gradually from vesicle.

Hemispermatophore: Adult male unknown.

Ontogenetic variation: The granulation and sclerotization of the chela are more pronounced in the adult than the juvenile.

Sexual dimorphism: Female unknown.

Geographical variation: Single complete specimen.

Remarks

The movable finger of the dextral pedipalp chela of the holotype is detached. A large, sinistral pedipalp chela, also without a movable finger, was collected together with the holotype and placed in the same vial. According to Sissom and Cokendolpher (1998: 289) this chela “structurally resembles the chela of Alacran tartarus 18Francke, 1982, known only from deep caves of the Sistema Huautla, Oaxaca … but until more material becomes available it will not be possible to draw comparisons with the Oaxacan specimens.” We compared the damaged chela with the types of A. tartarus and the holotype of S. granulosus and observed that, aside from its larger size, more pronounced granulation and sclerotization (all consistent with sexual maturity), the chela was otherwise identical to that of the holotype of S. granulosus. The proximal half of the fixed finger was granular dorsally, the median denticle row comprised seven oblique primary subrows, the basal subrow being the shortest, and there were six internal denticles. The chelal carination, though more pronounced, was consistent with the holotype of S. granulosus. Except for three trichobothria, which could not be observed due to damage to the specimen (V₁, Et₁, ib), the following 23 trichobothria were observed in the same positions as in the holotype of S. granulosus (fig. 18): 14 on manus, three ventral (V₃–V₄), nine external (Et₂–Et₅, Est, Esb, Eb₁–Eb₃), two dorsal (Db, Dt); nine on fixed finger, four external (et, est, esb, eb), four dorsal (dt, dst, dsb, db), one internal (it). Six of these trichobothria were petite, based on the smaller diameter of their areolae: Et₄, Et₅, Esb, Db, esb, db. The presence of seven primary subrows on the median denticle row of the fixed finger, six petite trichobothria, the absence of three accessory trichobothria, and other differences in trichobothrial positions rule out the possibility that the chela is conspecific with A. tartarus, or indeed that it is congeneric. Based on the overwhelming similarity of the chela to that of the holotype of S. granulosus, together with their collection from nearby one another in the same cave, we conclude that they are conspecific, that the chela belongs to an adult of the species and that the holotype is a juvenile. The discovery is significant because the length of the chela (at least 11 mm, as the tip of the finger is missing) is comparable to that of A. tartarus (12–14 mm), implying that the adult of S. granulosus may be similar in size (adult A. tartarus measure 60–70 mm in length), and hence that this would represent the second large-bodied species in the family, albeit from a much shallower cave (−73 m). The finding also calls into question whether some species of Typhlochactas, known only from single specimens and/or females (notably T. cavicola and T. reddelli), are adult and, if not, what size the adults might reach. In this regard, it is noteworthy that the second-largest typhlochactine specimen known, the holotype of T. sissomi, is subadult. Its total length is 0.3 mm greater than the adult male holotype of T. rhodesi and 0.9 mm greater than the adult male paratype of S. elliotti (tables 4, 5).

Distribution

Known only from the type locality, Sótano de Poncho (Veracruz, México) (fig. 1B).

Ecology

This troglobitic species was taken from a vertical cave, 95 m long and 73 m deep, with a small entrance (Sissom and Cokendolpher, 1998). The holotype was collected on the talus slope at the base of the entrance drop and the single pedipalp chela collected nearby.

Additional material

Mexico: Veracruz: Município Tlaquilpa: 1 ad., pedipalp chela only (AMNH), Sótano de Poncho [18°37′N 97°07′W, −73 m], P. Sprouse, 22.III.1995.

Diagnosis

Typhlochactas is the sister taxon of Stygochactas (fig. 4). Species of Typhlochactas may be separated from Stygochactas and Sotanochactas on the basis of the following combination of characters. Size small to very small, total length (adult) less than 25 mm. Cheliceral fixed finger with three or four teeth, basal teeth usually not fused into a bicusp. Cheliceral movable finger with three, four, or (usually) five dorsal teeth (none, one, or two subdistal teeth). Carapace, anterior margin, median projection (epistome) usually present. Pedipalps not elongated, chela fingers similar in length to chela manus. Pedipalp femur, ventroexternal carina, patella, internomedian carina, and chela, dorsal secondary, digital, ventroexternal, ventromedian, and ventrointernal carinae, absent or obsolete. Chela fixed and movable fingers, median denticle row comprising 4–6 and 5–7 oblique primary subrows, respectively; basal primary subrows of fixed finger similar in length to other subrows. Patella trichobothrium v₁ situated level with or proximal to trichobothrium esb₁. Chela fixed finger, external trichobothria distributed across entire length of finger, with trichobothrium eb situated near base of finger; trichobothria it and ib situated near base of finger. Legs usually with prolateral pedal spurs. Basitarsi I and II, proventral surfaces usually with short row of closely aligned spinules subdistally. Telotarsi, ventral surface, usually with curved proximal row spinules and without ventromedian row of spinules. Tergite VII, dorsolateral carinae absent or vestigial. Metasomal segments I–IV, dorsosubmedian carinae obsolete; I–III, dorsolateral carinae absent or obsolete; I, median lateral carinae absent; I–V, ventrolateral carinae absent or obsolete; V, ventromedian carina absent.

Included taxa

Six species: Typhlochactas cavicola Francke, 1986; Typhlochactas mitchelli Sissom, 1988; Typhlochactas reddelli Mitchell, 1968; Typhlochactas rhodesi Mitchell, 1968; Typhlochactas sissomi Francke et al., 2009; Typhlochactas sylvestris Mitchell and Peck, 1977.

Distribution

Endemic to Mexico. Recorded from four states: Oaxaca, Queretaro, Tamaulipas, Veracruz.

Fig. 23

Typhlochactas cavicola Francke, 1986, holotype ♀ (AMNH), habitus. A. Dorsal aspect. B. Ventral aspect. Scale  =  1 mm.

Fig. 24

Typhlochactas cavicola Francke, 1986, holotype ♀ (AMNH), sinistral pedipalp chela showing carinae and distribution of trichobothria. A. Dorsal aspect. B. External aspect. C. Ventral aspect. Scale  =  0.5 mm.

Fig. 25

Typhlochactas cavicola Francke, 1986, holotype ♀ (AMNH), sinistral pedipalp femur (A) and patella (B–D) showing carinae and distribution of trichobothria. A, B. Dorsal aspect. C. External aspect. D. Ventral aspect. Scales  =  0.5 mm.

TABLE 8

Meristic data for Typhlochactas cavicola Francke, 1986, Typhlochactas reddelli Mitchell, 1968, and Typhlochactas rhodesi Mitchell, 1968

Measurements (mm) follow Francke et al. (2009). Abbreviations as follows: AMNH  =  American Museum of Natural History, New York; IBUNAM  =  Instituto de Biología, Universidad Nacional Autonóma de México, Mexico City; MNHN  =  Muséum National d'Histoire Naturelle, Paris

Type material

Mexico: Tamaulipas: Município de Guemez: Holotype: 1 ♀ (AMNH), Cueva del Vandalismo [23°51′54″N 99°26′45″W], ca. 2600 m, 1 km SE Rancho Nuevo, D. Honea, 15.III.1982.

Diagnosis

Typhlochactas cavicola is most closely related to T. rhodesi (fig. 4). It may be separated from T. rhodesi and all other Typhlochactas species by the following combination of characters. Cheliceral fixed finger with four teeth (subdistal present); median and basal teeth not fused into bicusp. Cheliceral movable finger with four dorsal teeth (one subdistal present). Carapace, anterior margin, median projection (epistome) absent. Pedipalp chela fixed and movable fingers, median denticle row comprising six and five oblique primary subrows, respectively; basal primary subrow of movable finger considerably longer than other subrows; terminal denticle of fixed finger slightly larger than preceding denticles, fingertips interlocking evenly when closed. Legs without prolateral pedal spurs. Telotarsi without ventromedian row of spinules. Sclerites of genital operculum (♀) mostly fused, but loosely connected by membrane along entire length of suture, posterior edges free.

Description

The following description supplements the original description by Francke (1986).

Color: Carapace, pedipalps, legs, tergites, and metasoma, Raw Sienna (136). Pedipalp chela fingers darker; cheliceral teeth, ungues paler than aculeus (fig. 23).

Chelicerae: Manus, dorsal and ventral surfaces smooth; dorsal surface with three microsetae situated near base of fixed finger; movable finger with two larger microsetae and one smaller microseta. Fixed finger, dorsal margin with four teeth (distal, subdistal, median, and basal; fig. 5D); median and basal teeth not fused into bicusp; distal tooth largest, subdistal and median teeth equal, smaller, basal tooth smallest. Movable finger, internal distal and external distal teeth opposable, internal distal tooth completely overlapping external distal tooth in dorsal view; dorsal margin with four teeth (internal distal, subdistal, median, and basal), internal distal tooth largest, subdistal and median teeth equal, smaller, basal tooth smallest; ventral surface with well-developed serrula, covered in part by dense brush of macrosetae.

Carapace: Length slightly greater than anterior width (table 8). Anterior margin sublinear, without median projection (epistome); asetose (fig. 23A). Posterior margin sublinear; asetose. Median and lateral ocelli absent. Median longitudinal, posterolateral and posterior transverse sulci shallow. Surface smooth, acarinate, with few microsetae.

Pedipalps: Femur, dorsoexternal, ventroexternal, and ventrointernal carinae obsolete, comprising a few small scattered granules, decreasing in number distally; dorsointernal carina absent. Dorsal and external surfaces smooth, with several short setae (fig. 25A); internal surface with few granules proximally. Patella, ventrointernal carina obsolete, granular; other carinae absent (fig. 25B–D). Intercarinal surfaces less granular than femur, with several short setae. Chela relatively large, longer than carapace (table 8). Manus acarinate (fig. 24); manus and fingers, surfaces mostly smooth, with several long setae; dorsal, external, and internal surfaces with small scattered granules; internal surface additionally with pair of prominent, isolated granules situated close together at base of fixed finger. Fixed finger, median denticle row comprising six oblique primary subrows (fig. 9G); internal denticles larger than external denticles; terminal denticle small, equal to internal denticle, fingertips interlocking evenly when closed. Movable finger, median denticle row comprising five oblique primary subrows of denticles, basal primary subrow considerably longer than other subrows (fig. 9H); terminal denticle small.

Trichobothria: Femur with three trichobothria (fig. 25A): one external (e), one dorsal (d), one internal (i). Patella with 19 trichobothria (fig. 25B–D), five petite (d₁, d₂, et₂, esb₂, eb₂), one accessory (em₃): two ventral (v₁, v₂); 14 external (et₁–et₃, est, em₁–em₃, esb₁, esb₂, eb₁–eb₅); two dorsal (d₁, d₂); one internal (i). Chela with 26 trichobothria (fig. 24), seven petite (V₁, Et₄, Et₅, Esb, Db, esb, db): 16 on manus, four ventral (V₁–V₄), 10 external (Et₁–Et₅, Est, Esb, Eb₁–Eb₃), two dorsal (Db, Dt); 10 on fixed finger, four external (et, est, esb, eb), four dorsal (dt, dst, dsb, db), two internal (it, ib).

Legs: All segments smooth, setose, especially telotarsi. Basitarsi I–IV without prolateral pedal spurs; I and II, proventral surface with short subdistal row of closely aligned spinules. Telotarsi, dorsomedian lobe with one microseta; ventral surface with curved row of spinules, proximally, and four or five submedian pairs of subspiniform macrosetae; ungues well developed, curved, equal in length; dactyl long, prominent.

Tergites: Surfaces I–VI, smooth, acarinate; VII, mostly smooth, posterolateral surfaces granular, dorsosubmedian carinae vestigial, reduced to few posterior granules, dorsolateral carinae absent (fig. 23A). Lateral and posterior margins setose.

Sternum: Posterior width slightly greater than length (fig. 8C); apex rounded; lateral margins converging anteriorly; lateral lobes flat; posterior depression moderate. Surfaces with few macrosetae.

Genital operculum: Sclerites mostly fused, but loosely connected by membrane along entire length of suture, posterior edges free (fig. 8C); suboval, each with pair of macrosetae and several microsetae on margin.

Pectines: Pectinal plate, surface with pair of macrosetae. Lamella comprising three segments (fig. 8C); surfaces with several macrosetae and microsetae. Tooth count, 5/5; teeth equal to subequal, except for distal tooth, larger, pointed.

Sternites: Surfaces smooth, acarinate (fig. 23B); surfaces and margins with several microsetae. Respiratory spiracles (stigmata) small, round, situated posterolaterally.

Metasoma: Segments elongated, progressively increasing in length, decreasing in width (fig. 12C), I and II width greater than length, III–V length greater than width (table 8). Dorsosubmedian carinae, segments I–IV, obsolete, granular, distal granules not noticeably larger than preceding granules (fig. 12C). Dorsolateral carinae, segment V, obsolete, granular. Dorsolateral, median lateral, and ventrosubmedian carinae, segments I–IV, ventrolateral carinae, segments I–V, and ventromedian carina, segment V, absent. Dorsal intercarinal surfaces, segments I–V, slightly concave, uniformly finely granular; other surfaces smooth. All segments setose.

Telson: Vesicle broad, elongated, flattened dorsally, rounded ventrally; anterodorsal lateral lobes absent (fig. 12C); surface smooth, setae distributed uniformly across ventral surface. Aculeus short, slightly curved, arising gradually from vesicle.

Hemispermatophore: Male unknown.

Ontogenetic variation: It is unclear whether the holotype female is adult.

Sexual dimorphism: Male unknown.

Geographical variation: Single specimen.

Remarks

Francke (1986: 5, 6) described the holotype as a male and stated that the genital opercula were “without membranous connection,” but noted that genital papillae “could not be detected.” We confirmed the absence of genital papillae but observed that the genital opercula are mostly fused, being loosely connected by a membrane along the entire length of the suture, although the posterior edges are free. These observations, together with the shape of the pectinal teeth, lead us to conclude that the holotype is female. Males of all other typhlochactid species display genital papillae and divided genital opercula.

Distribution

Known only from the type locality, Cueva del Vandalismo, in the Sistema Purificación karstic region, northwest of Ciudad Victoria, Tamaulipas (central-eastern Mexico) (fig. 1B).

Ecology

No additional data are available for the cave from which this troglobitic species was collected.

Fig. 26

Typhlochactas mitchelli Sissom, 1988, holotype ♂ (AMNH), habitus. A. Dorsal aspect. B. Ventral aspect. Scale  =  1 mm.

Fig. 27

Typhlochactas mitchelli Sissom, 1988, holotype ♂ (AMNH), sinistral pedipalp chela showing carinae and distribution of trichobothria. A. Dorsal aspect. B. External aspect. C. Ventral aspect. Scale  =  0.1 mm.

Fig. 28

Typhlochactas mitchelli Sissom, 1988, holotype ♂ (AMNH), sinistral pedipalp femur (A) and patella (B–D) showing carinae and distribution of trichobothria. A, B. Dorsal aspect. C. External aspect. D. Ventral aspect. Scales  =  0.1 mm.

Type material

Mexico: Oaxaca: Município de San José Tenango: Holotype: 1 ♂ (AMNH), Cerro Ocote [18°08′57.5″N 96°43′59.1″W], 5 mi. S San José de Tenango, A. Grubbs, A. Cressler and P. Smith, IV.1987. Paratypes: 1 ♂, 1 subad. ♀ (AMNH), same data.

Diagnosis

Typhlochactas mitchelli is most closely related to T. sylvestris (fg. 4). It may be separated from T. sylvestris and all other Typhlochactas species by the following combination of characters. Cheliceral fixed finger with three teeth (subdistal absent); median and basal teeth not fused into bicusp. Cheliceral movable finger with three dorsal teeth (subdistal teeth absent). Carapace, anterior margin with well-developed median projection (epistome). Pedipalp chela fixed and movable fingers, median denticle row comprising four or five and five or six oblique primary subrows, respectively; basal primary subrow of movable finger similar in length to other subrows; terminal denticle of fixed finger slightly larger than preceding denticles, fingertips interlocking evenly when closed. Legs with prolateral pedal spurs. Telotarsi with ventromedian row of spinules. Sclerites of genital operculum (♀) fused, but loosely connected by membrane along entire length of suture.

Description

The following description supplements the original description by Sissom (1988).

Color: Holotype and paratype ♂, pedipalp femur, patella, and mesosoma, Yellow Ocher (123C); pedipalp chela and telson, Robin Rufous (340); metasoma, Brick Red (132A). Subadult ♀ paratype, uniformly Buff (124).

Chelicerae: Manus, dorsal and ventral surfaces smooth; dorsal surface with three microsetae near base of fixed finger; movable finger with single microseta. Fixed finger, dorsal margin with three teeth (distal, median and basal; fig. 5E); median and basal teeth equal, not fused into bicusp, considerably smaller than distal tooth. Movable finger, internal distal and external distal teeth not opposable, internal distal tooth at most partially overlapping external distal tooth in dorsal view; dorsal margin with three teeth (internal distal, median, and basal), internal distal tooth largest, median smallest; ventral surface with serrula extending two-thirds of finger, covered in part by dense brush of macrosetae.

Carapace: Length greater than anterior width (table 9). Anterior margin sublinear, with small median projection (epistome); asetose (fig. 26A). Posterior margin weakly concave medially; asetose. Median and lateral ocelli absent. Median longitudinal, posterolateral, and posterior transverse sulci shallow. Surface smooth to finely granular, acarinate, with scattered microsetae.

TABLE 9

Meristic data for Typhlochactas mitchelli Sissom, 1988, and Typhlochactas sylvestris Mitchell and Peck, 1977

Measurements (mm) follow Francke et al. (2009). Abbreviations as follows: AMNH  =  American Museum of Natural History, New York

Pedipalps: Femur, ventroexternal carina obsolete, granular, dorsoexternal carina vestigial, restricted to proximal third; other carinae absent; intercarinal surfaces moderately granular (fig. 28A). Patella acarinate; intercarinal surfaces moderately granular (fig. 28B–D). Chela stout, with broad, rounded manus (fig. 27); fingers short, slightly longer than manus (table 9). Manus acarinate; dorsointernal and, to a lesser extent, dorsoexternal surfaces, markedly granular distally; fixed and movable fingers, proximal surfaces, markedly granular, without denticle rows. Fixed finger, median denticle row comprising four or five oblique primary subrows, restricted to distal two-thirds of finger (fig. 9I); internal denticles larger than external denticles; terminal denticle small, slightly larger than preceding denticles, fingertips interlocking evenly when closed. Movable finger, median denticle row comprising five or six oblique primary subrows, restricted to distal two-thirds of finger (Fig. 9J); basal primary subrow short, similar in length to distal subrow; terminal denticle small.

Trichobothria: Femur with three trichobothria (fig. 28A): one external (e), one dorsal (d), one internal (i). Patella with 19 trichobothria (fig. 28B–D), five petite (d₁, d₂, et₂, esb₂, eb₂), one accessory (em₃): two ventral (v₁, v₂); 14 external (et₁–et₃, est, em₁–em₃, esb₁, esb₂, eb₁–eb₅); two dorsal (d₁, d₂); one internal (i). Chela with 26 trichobothria (fig. 27), seven petite (V₁, Et₄, Et₅, Esb, Db, esb, db): 16 on manus, four ventral (V₁–V₄), 10 external (Et₁–Et₅, Est, Esb, Eb₁–Eb₃), two dorsal (Db, Dt); 10 on fixed finger, four external (et, est, esb, eb), four dorsal (dt, dst, dsb, db), two internal (it, ib).

Legs: All segments setose; basitarsi, ventral surface with three or four pairs of macrosetae. Basitarsi I–IV with prolateral pedal spurs; I and II, proventral surface with short subdistal row of closely aligned spinules. Telotarsi, dorsomedian lobe with one microseta; ventral surface with curved row of spinules, proximally, and straight ventromedian row of spinules, flanked by three or four submedian pairs of subspiniform macrosetae; ungues moderately developed, equal in length; dactyl short, robust.

Tergites: Surfaces acarinate; I–V, smooth, VI and VII sparsely, coarsely granular (fig. 26A). Surfaces and margins with sparse microsetae.

Sternum: Posterior width greater than length (fig. 8B); apex slightly rounded; lateral margins subparallel; lateral lobes flat; posterior depression very shallow. Surface with approximately 10 microsetae.

Genital operculum: Sclerites (♂) suboval, completely divided; genital papillae large, protruding distinctly beyond posterior edges (fig. 8B). Sclerites (♀) fused, but loosely connected by membrane along entire length of suture. Surfaces with few microsetae.

Pectines: Pectinal plate, surface with several microsetae. Lamella comprising five segments (fig. 8B); surfaces covered with microsetae. Tooth count, 5/5; teeth similar in shape and size, except for distal tooth, slightly enlarged, lobate.

Sternites: Surfaces acarinate, smooth, sparsely setose (fig. 26B). Respiratory spiracles (stigmata) small, round, situated posterolaterally.

Metasoma: Metasoma stout, segments I–III width greater than length, IV and V length greater than width (fig. 12D), progressively increasing in length, decreasing in width (table 9); segment V longer than carapace. Dorsosubmedian carinae, segments I–IV, obsolete, distal granules not noticeably larger than preceding granules (fig. 12D). Dorsolateral carinae, segment V, obsolete. Dorsolateral, median lateral and ventrosubmedian carinae, segments I–IV, ventrolateral carinae, segments I–V, and ventromedian carina, segment V, absent. Dorsal intercarinal surfaces, segments I–V, slightly concave. Segments I–IV, dorsolateral surfaces coarsely granular, other intercarinal surfaces smooth; segment V entirely granular except posteroventrally. Surfaces of all segments with short microsetae; V additionally with several longer macrosetae.

Telson: Vesicle globose, wider than segments II–V (table 9), flattened to slightly concave dorsally, rounded ventrally; anterodorsal lateral lobes absent (fig. 12D); lateral and ventral surfaces granular, with several long and short setae posteriorly. Aculeus short, moderately curved, arising abruptly from vesicle.

Hemispermatophore: Unknown (neither adult male specimens dissected).

Ontogenetic variation: Paler, cream coloration and less elongated, more rounded telson of subadult female attributed to ontogenetic rather than sexual variation. Subadult female retains vestigial subrows of denticles extending to near base of chela fixed and movable fingers (i.e., five subrows on fixed finger, six on movable finger) and there are no internal denticles on fourth row of fixed finger or fifth row of movable finger. These observations suggest a reduction in number of subrows in the adult occurs at the final instar (Sissom, 1988) or else that it is a sexually dimorphic character.

Sexual dimorphism: Males exhibit more pronounced granulation, completely divided genital operculum and genital papillae.

Geographical variation: All specimens from same locality.

Remarks

Typhlochactas mitchelli and T. sylvestris are the smallest species of the family and among the smallest known scorpions. Adults measure less than 10 mm in total length (table 9).

Distribution

Known only from the type locality, Cerro Ocote, near San José de Tenango, Oaxaca, Mexico (fig. 1B). This locality is part of the same mountain range (Sistema Montañoso Poblano Oaxaqueño) in which T. sylvestris was collected.

Ecology

This endogean (humicolous) species was hand-collected from the surfaces of small stones 1 to 2 feet below the surface, in crevices and alongside rock faces excavated from beneath leaf litter, wood debris, roots, small stones and slight amounts of soil, in a montane forest (A.G. Grubbs, personal commun.). This habitat is very similar to that of Belisarius xambeui, an endogean scorpion from the Pyrenees of France and Spain, often found under stones deeply embedded in forest litter (Auber, 1959).

Fig. 29

Typhlochactas reddelli Mitchell, 1968, holotype ♀ (AMNH), habitus. A. Dorsal aspect. B. Ventral aspect. Scale  =  1 mm.

Fig. 30

Typhlochactas reddelli Mitchell, 1968, holotype ♀ (AMNH), sinistral pedipalp chela showing carinae and distribution of trichobothria. A. Dorsal aspect. B. External aspect. C. Ventral aspect. Scale  =  0.5 mm.

Fig. 31

Typhlochactas reddelli Mitchell, 1968, holotype ♀ (AMNH), sinistral pedipalp femur (A) and patella (B–D) showing carinae and distribution of trichobothria. A, B. Dorsal aspect. C. External aspect. D. Ventral aspect. Scales  =  0.5 mm.

Type material

Mexico: Veracruz: Município de Tlilapan: Holotype: 1 ♀ (AMNH), La Cueva del Ojo de Agua de Tlilapan, Tlilapan, ca. 5 km S Orizaba [18°48′23″N 97°05′59″W], 1400 m, J. Reddell, J. Fish and T.R. Evans, 4.VIII.1967.

Diagnosis

Typhlochactas reddelli is most closely related to the monophyletic group comprising T. mitchelli and T. sylvestris (fig. 4). It may be separated from these and other Typhlochactas species by means of the following combination of characters. Cheliceral fixed finger with four teeth (subdistal present); median and basal teeth fused into a bicusp. Cheliceral movable finger with five dorsal teeth (two subdistals present). Carapace, anterior margin with well-developed median projection (epistome). Pedipalp chela fixed and movable fingers, median denticle row comprising six and seven primary subrows, respectively; basal primary subrow of movable finger similar in length to other subrows; terminal denticle of fixed finger considerably larger than preceding denticles, hooklike, fingertips interlocking unevenly when closed. Legs with prolateral pedal spurs. Telotarsi without ventromedian row of spinules. Sclerites of genital operculum (♀) fused, but loosely connected by membrane along entire length of suture.

Description

The following description of the holotype (fig. 29) supplements the original description by Mitchell (1968) and additional data provided by Mitchell (1971) and Francke (1982a, 1986).

Color: Carapace, pedipalp femur and patella, legs, tergites, sternites, metasoma, and telson, Yellow Ocher (123C); pedipalp chela, Pratt's Rufous (140). Aculeus and denticle rows of pedipalp fingers darker.

Chelicerae: Manus, dorsal and ventral surfaces smooth; dorsal surface with two microsetae situated near base of fixed finger; movable finger, dorsal surface with two microsetae. Fixed finger, dorsal margin with four teeth (distal, subdistal, median, and basal; fig. 5F); distal tooth largest, median and basal teeth equal, fused into bicusp. Movable finger, internal distal and external distal teeth opposable, internal distal tooth completely overlapping external distal tooth in dorsal view; dorsal margin with five closely aligned teeth (internal distal, two subdistal, median, and basal) situated on slightly convex ridge, internal distal tooth largest, median tooth slightly larger than subdistal and basal teeth (all similar in dimensions); ventral surface with serrula covering almost entire length of finger, comprising long tines, all equal in length, partially covered by dense brush of macrosetae.

Carapace: Length greater than anterior width (table 8). Anterior margin weakly concave, with small median projection (epistome) and few microsetae (fig. 29A). Posterior margin weakly convex; asetose. Median and lateral ocelli absent. Median longitudinal, posterolateral and posterior transverse sulci shallow. Surface acarinate, smooth, with few microsetae.

Pedipalps: Femur, ventroexternal carina obsolete, granular; other carinae absent (fig. 31A). Intercarinal surfaces mostly smooth, with few small granules proximally, and covered with microsetae. Patella longer than femur (table 8); acarinate, with three granules on ventrointernal margin (fig. 31B–D). Intercarinal surfaces covered with microsetae. Chela stout, fingers relatively short, slightly longer than manus (table 8). Manus acarinate (fig. 30); surfaces mostly smooth; dorsal and ventral surfaces with few granules distally; internal surface with pair of prominent, isolated granules situated close together at base of fixed finger; fingers, internal and external surfaces setose. Fixed finger, median denticle row comprising six oblique primary subrows, terminal subrow shorter, third subrow longer than other subrows (fig. 9K); internal denticles larger than external denticles; terminal denticle considerably larger than preceding denticles, hooklike, fingertips interlocking unevenly when closed. Movable finger, median denticle row comprising seven oblique primary subrows, terminal subrow shorter, basal subrow slightly longer than other subrows (fig. 9L); terminal denticle smaller than on fixed finger.

Trichobothria: Femur with three trichobothria (fig. 31A): one external (e), one dorsal (d), one internal (i). Patella with 19 trichobothria (fig. 31B–D), five petite (d₁, d₂, et₂, esb₂, eb₂), one accessory (em₃): two ventral (v₁, v₂); 14 external (et₁–et₃, est, em₁–em₃, esb₁, esb₂, eb₁–eb₅); two dorsal (d₁, d₂); one internal (i). Chela with 26 trichobothria (fig. 30), seven petite (V₁, Et₄, Et₅, Esb, Db, esb, db): 16 on manus, four ventral (V₁–V₄), 10 external (Et₁–Et₅, Est, Esb, Eb₁–Eb₃), two dorsal (Db, Dt); 10 on fixed finger, four external (et, est, esb, eb), four dorsal (dt, dst, dsb, db), two internal (it, ib).

Legs: All segments smooth, setose, especially femora and telotarsi. Basitarsi I and II, proventral surface with short subdistal row of closely aligned spinules; I–IV with prolateral pedal spurs. Telotarsi, dorsomedian lobe with one microseta; ventral surface without spinules, and with four or five ventrosubmedian pairs of subspiniform macrosetae; ungues long, well developed, curved, equal in length; dactyl short, slightly curved.

Tergites: Surfaces I–VI, smooth, acarinate; VII, mostly smooth, granular posterolaterally, dorsosubmedian carinae vestigial, reduced to few posterior granules, dorsolateral carinae absent (fig. 29A). Lateral and posterior margins with microsetae.

Sternum: Posterior width greater than length; apex rounded; lateral margins subparallel; lateral lobes flat; posterior depression shallow. Surface sparsely covered with microsetae.

Genital operculum: Sclerites (♂) completely divided; genital papillae protruding distinctly beyond posterior edges of opercula. Sclerites (♀) fused, but loosely connected by membrane along entire length of suture.

Pectines: Pectinal plate, surface with two macrosetae situated mediolaterally. Lamella comprising three segments, demarcated by faint sutures; surfaces covered with microsetae. Tooth count, 5/5; teeth oval; proximal and distal teeth slightly larger.

Sternites: Surfaces acarinate, smooth (fig. 29B). Surfaces and margins with few, scattered setae. Respiratory spiracles (stigmata) small, round, situated posterolaterally.

Metasoma: Segments elongated, progressively increasing in length, decreasing in width (table 8), I and II width greater than length, III width equal to length, IV and V length greater than width. Dorsosubmedian carinae, segments I–IV, obsolete, composed of few stout granules, distal granules not noticeably larger than preceding granules. Dorsolateral carinae, segment V, obsolete, complete. Ventrolateral carinae, segment V, obsolete, complete, comprising spiniform granules increasing in size posteriorly. Dorsolateral, median lateral, ventrolateral, and ventrosubmedian carinae, segments I–IV, and ventromedian carina, segment V, absent. Dorsal intercarinal surfaces, segments I–V, slightly concave, smooth. All segments setose, especially on ventral and lateral surfaces. Anal arch with macro- and microsetae and few granules ventrolaterally.

Telson: Vesicle globose, shorter than metasomal segment V (table 8), flattened dorsally, rounded ventrally; anterodorsal lateral lobes absent; surfaces mostly smooth, with scattered granules near base of aculeus; ventral surface with scattered long and short macrosetae, increasing in number posteriorly. Aculeus short, weakly curved, arising gradually from vesicle (fig. 12E).

Hemispermatophore: Adult male unknown.

Ontogenetic variation: Juveniles paler in coloration.

Sexual dimorphism: Adult male unknown. Juvenile male exhibits completely divided genital operculum and genital papillae.

Geographical variation: All specimens from same locality.

Remarks

The holotype is severely damaged (fig. 29): the mesosoma is broken, the metasoma broken in two places, and dextral leg II is disarticulated.

Distribution

Known only from the type locality, La Cueva del Ojo de Agua de Tlilapan, in the karstic region of Orizaba, Veracruz (eastern Mexico) (figs. 1B, 2A, 2B).

Ecology

The cave in which this troglobitic species was collected, comprises two large horizontal rooms and a wide entrance (Mitchell, 1968; Reddell, 1981). According to the original description (Mitchell, 1968), the holotype was collected in the first bat room, approximately 30 m from the cave entrance immediately after a low, narrow passage separating it from the entrance room. The specimen was found beneath a stone on guano, although not near the main guano deposits. Subsequently collected specimens were also taken from under stones.

Additional material

Mexico: Veracruz: Município de Tlilapan: 1 juv. ♀ (IBUNAM), Cueva Ojo de Agua, Tlilapan, R. Sanchez, 8.II.1990; 1 juv. ♂ (IBUNAM), same locality, I. Vazquez, 30.III.1990, under rock; 1 juv. ♀ (IBUNAM), same locality, I. Vazquez, 30.III.1990, under rock, dark zone.

Fig. 32

Typhlochactas rhodesi Mitchell, 1968, holotype ♀ (AMNH), habitus. A. Dorsal aspect. B. Ventral aspect. Scale  =  1 mm.

Fig. 33

Typhlochactas rhodesi Mitchell, 1968, holotype ♀ (AMNH), sinistral pedipalp chela showing carinae and distribution of trichobothria. A. Dorsal aspect. B. External aspect. C. Ventral aspect. Scale  =  0.5 mm.

Fig. 34

Typhlochactas rhodesi Mitchell, 1968, holotype ♀ (AMNH), sinistral pedipalp femur (A) and patella (B–D) showing carinae and distribution of trichobothria. A, B. Dorsal aspect. C. External aspect. D. Ventral aspect. Scales  =  0.5 mm.

Type material

Mexico: Tamaulipas: Município de Gómez Farias: Holotype: 1 ♀ (AMNH), La Cueva de la Mina, Sierra de Guatemala [23°06′06″N 99°12′56″W], 1600 m, R.W. and R. Mitchell, K. Pittard, D. Falls, and V. Colvin, 24.III.1967. Paratypes: 1 subad. ♀ (AMNH), same locality, R.W. Mitchell, F. Abernethy and W. Rhodes, 29–30.VIII.1966; 1 ♀ (MNHN RS 4760), same locality, R.W. Mitchell, F. Abernethy and W. Rhodes, 29.VIII.1967.

Diagnosis

Typhlochactas rhodesi is most closely related to T. cavicola (fig. 4). It may be separated from T. cavicola and all other Typhlochactas species by the following combination of characters. Cheliceral fixed finger with four teeth (subdistal present); median and basal teeth not fused into bicusp. Cheliceral movable finger with five dorsal teeth (two subdistals present). Carapace, anterior margin with well-developed median projection (epistome). Pedipalp chela fixed and movable fingers, median denticle row of each comprising six oblique primary subrows; basal primary subrow of movable finger considerably longer than other subrows; terminal denticle of fixed finger slightly larger than preceding denticles, fingertips interlocking evenly when closed. Legs without prolateral pedal spurs. Telotarsi without ventromedian row of spinules. Sclerites of genital operculum (♀) fused, but loosely connected by membrane along entire length of suture.

Description

The following description supplements the original description of Mitchell (1968) and additional data provided by Mitchell (1971) and Francke (1982a, 1986).

Color: Carapace, pedipalp femur and patella, legs, tergites, sternites, metasoma, and telson, Yellow Ocher (123C); pedipalp chela, Pratt's Rufous (140). Aculeus and denticle rows of pedipalp fingers darker. Larger paratype (AMNH) uniformly Buff Yellow (53); smaller paratype (MNHN) paler, except for aculeus and pedipalp finger denticles, Chamois (123D).

Chelicerae: Manus, dorsal and ventral surfaces smooth; dorsal surface with three microsetae situated near base of fixed finger; movable finger, dorsal surface with six microsetae. Fixed finger, dorsal margin with four teeth (distal, subdistal, median, and basal; fig. 5G); median and basal teeth not fused into bicusp; distal tooth largest, subdistal and median teeth equal, smaller, basal tooth smallest. Movable finger, internal distal and external distal teeth opposable, internal distal tooth completely overlapping external distal tooth in dorsal view; dorsal margin with five closely aligned teeth (internal distal, two subdistal, median, and basal), first subdistal, second subdistal and median teeth progressively increasing in size, basal tooth equal to second subdistal tooth; ventral surface with well-developed serrula, extending half length of finger; macrosetae on proximal third of finger only, not covering serrula.

Carapace: Length slightly greater than anterior width (table 8). Anterior margin sublinear to weakly convex, with small median projection (epistome) and few microsetae (fig. 32A). Posterior margin sublinear to weakly convex; asetose. Median and lateral ocelli absent. Median longitudinal and posterolateral sulci shallow; posterior transverse sulcus deep. Surface acarinate, smooth except for posterolateral margins, which are weakly granular, with scattered microsetae.

Pedipalps: Femur, dorsoexternal and ventroexternal carinae obsolete, granular; dorsointernal and ventrointernal carinae absent (fig. 34A). Dorsal and ventral surfaces mostly smooth; external and internal surfaces with scattered granules proximally; all surfaces, especially external surfaces, setose. Patella dorsoexternal carina distinct, granular; dorsointernal and ventrointernal carinae obsolete; other carinae absent. Dorsal and external surfaces less granular than femur, mostly smooth except for small granules concentrated around trichobothria (figs. 34B–D); ventral and internal surfaces with small, scattered granules; ventral surface asetose. Chela longer than carapace, relatively stout, manus length greater than width (table 8); movable finger slightly longer than manus. Manus acarinate (fig. 33); internal surface with depression near base of movable finger; manus and fingers, surfaces mostly smooth with scattered setae; dorsal, external, and internal surfaces with small, scattered granules distally near base of fingers; internal surface additionally with pair of prominent, isolated granules situated close together at base of fixed finger; ventroexternal surface with small group of granules proximally. Fixed finger, median denticle row comprising six oblique primary subrows, terminal subrow shorter, basal subrow slightly longer than other subrows (fig. 9M); internal denticles larger than external denticles; terminal denticle small, equal to internal denticle, fingertips interlocking evenly when closed. Movable finger, median denticle row comprising six oblique primary subrows, terminal subrow shorter, basal subrow considerably longer than other subrows (fig. 9N); terminal denticle small.

Trichobothria: Femur with three trichobothria (fig. 34A): one external (e), one dorsal (d), one internal (i). Patella with 19 trichobothria (fig. 34B–D), five petite (d₁, d₂, et₂, esb₂, eb₂), one accessory (em₃): two ventral (v₁, v₂); 14 external (et₁–et₃, est, em₁–em₃, esb₁, esb₂, eb₁–eb₅); two dorsal (d₁, d₂); one internal (i). Chela with 26 trichobothria (Fig. 33), seven petite (V₁, Et₄, Et₅, Esb, Db, esb, db): 16 on manus, four ventral (V₁–V₄), 10 external (Et₁–Et₅, Est, Esb, Eb₁–Eb₃), two dorsal (Db, Dt); 10 on fixed finger, four external (et, est, esb, eb), four dorsal (dt, dst, dsb, db), two internal (it, ib).

Legs: All surfaces with scattered microsetae; basitarsi with fewer setae than telotarsi. Basitarsi I–IV without prolateral pedal spurs; I and II, proventral surfaces with short subdistal row of closely aligned spinules. Telotarsi, dorsomedian lobe with one microseta; ventral surface with curved row of spinules, proximally, and six or seven submedian pairs of subspiniform macrosetae; ungues long, equal in length; dactyl short, slightly curved.

Tergites: Surfaces acarinate; I–VI, uniformly smooth; VII, mostly smooth, with few small granules posterolaterally (fig. 32A). Posteromedian surfaces with paired setae; lateral and posterior margins, especially of tergites V and VI, with microsetae.

Sternum: Posterior width equal to length (fig. 7C); apex rounded; lateral margins converging anteriorly; lateral lobes flat; posterior depression shallow. Surface with four macrosetae anteromedially and two macrosetae posterolaterally.

Genital operculum: Sclerites fused, but loosely connected by membrane along entire length of suture; anterior margins rounded (fig. 7C); microsetae situated close to median suture and posterior margins.

Pectines: Pectinal plate, surface with two macrosetae situated mediolaterally. Lamella comprising four segments (fig. 7C); surfaces covered in microsetae, larger along margins. Tooth count, 5/5; teeth oval; proximal and distal teeth slightly larger.

Sternites: Surfaces acarinate, smooth (fig. 32B). Surfaces and margins setose. Respiratory spiracles (stigmata) small, round, situated posterolaterally.

Metasoma: Segments elongated, progressively increasing in length, decreasing in width (fig. 12F), segment I width greater than length, II width equal to length, III–V length greater than width (table 8); segment V slightly shorter than carapace. Dorsosubmedian carinae, segments I–IV, obsolete, granular, distal granules not noticeably larger than preceding granules (fig. 12F). Dorsolateral carinae, segment V, obsolete, granular, present only in anterior part of segment. Dorsolateral, median lateral and ventrosubmedian carinae, segments I–IV, ventrolateral carinae, segments I–V, and ventromedian carina, segment V, absent. Dorsal intercarinal surfaces, segments I–V, slightly concave, uniformly, finely granular; other surfaces smooth. Lateral and ventral surfaces of all segments with several macrosetae.

Telson: Vesicle globose, flattened dorsally, rounded ventrally; anterodorsal lateral lobes absent (fig. 12F); surfaces smooth; ventral surface with several long and short setae. Aculeus short, slightly curved, arising gradually from vesicle.

Hemispermatophore: Male unknown.

Ontogenetic variation: Subadult similar to adults in general proportions but lacks depression and granules on pedipalp chela internal surface.

Geographical variation: All specimens from same locality.

Sexual dimorphism: Male unknown.

Remarks

The label with the holotype indicates a different collecting date, “29.III.1967,” to that listed in the original description (Mitchell, 1968: 762), “24.III.1967.” The specimen listed as “depositary unknown” by Sissom (2000b: 499) is deposited at the AMNH. The specimen at the MNHN is damaged (probably by dehydration): the sinistral pedipalp is lost, telson dislocated, mesosoma opened and metasoma broken.

Distribution

Known only from the type locality, La Cueva de la Mina, in the Sierra de Guatemala, Tamaulipas, Mexico (figs. 1B, 3A, 3B), a karstic region characterized by many vertical caves ranging from a few meters to more than 100 m in depth (Mitchell, 1968; Reddell, 1981).

Ecology

The holotype and paratypes of this troglobitic species were taken in a small room, about 50 m from the entrance to the cave, floored by a dark soil that apparently entered through small cracks in the overburden (Mitchell, 1968).

Fig. 35

Typhlochactas sissomi Francke et al., 2009, subadult ♂ holotype (IBUNAM), habitus. A. Dorsal aspect. B. Ventral aspect. Scale  =  1 mm.

Fig. 36

Typhlochactas sissomi Francke et al., 2009, subadult ♂ holotype (IBUNAM), sinistral pedipalp chela showing carinae and distribution of trichobothria. A. Dorsal aspect. B. External aspect. C. Ventral aspect. Scale  =  0.5 mm.

Fig. 37

Typhlochactas sissomi Francke et al., 2009, subadult ♂ holotype (IBUNAM), sinistral pedipalp femur (A) and patella (B–D) showing carinae and distribution of trichobothria. A, B. Dorsal aspect. C. External aspect. D. Ventral aspect. Scales  =  0.5 mm.

Type material

Mexico: Queretaro: Município de Jalpan: Holotype: 1 subadult ♂ (IBUNAM T-0308), leg (AMCC [LP 2949]), Cañada de La Joya, 21°27′23″N 99°08′26″W, 1944 m, H. Montaño and A. Valdez, 12.vi.2004, rock-rolling.

Diagnosis

Typhlochactas sissomi is the sister taxon of a monophyletic group comprising all other species of Typhlochactas, from which it may be separated on the basis of the following combination of characters. Cheliceral fixed finger with four teeth (subdistal present); median and basal teeth not fused into bicusp. Cheliceral movable finger with five dorsal teeth (two subdistals present). Carapace, anterior margin with well-developed median projection (epistome). Pedipalp chela fixed and movable fingers, median denticle row of each comprising six oblique primary subrows; basal primary subrow of movable finger longer than other subrows; terminal denticle of fixed finger slightly larger than preceding denticles, fingertips interlocking evenly when closed. Legs with prolateral pedal spurs. Telotarsi without ventromedian row of spinules.

Description

The following description of the holotype (fig. 33) supplements the original description by Francke et al. (2009).

Color: Cheliceral manus, Cream (54), teeth Amber (36). Carapace, pedipalps, tergites, and metasoma, Buff Yellow (53). Coxosternal region, legs, sternites, and telson vesicle, Cream (54). Telson aculeus, Raw Sienna (136).

Chelicerae: Manus, dorsal and ventral surfaces smooth; dorsal surface with few microsetae. Fixed finger, dorsal margin with four teeth (distal, subdistal, median and basal; fig. 5H); median and basal teeth equal, not fused into bicusp. Movable finger, internal distal and external distal teeth opposable, internal distal tooth completely overlapping external distal tooth in dorsal view; dorsal margin with five teeth (internal distal, two subdistal, median and basal), internal distal tooth largest; ventral surface with prominent serrula, partially covered by dense brush of macrosetae.

Carapace: Length greater than anterior width (table 7). Anterior margin sublinear, with small median projection (epistome); asetose (fig. 35A). Posterior margin weakly convex; asetose. Median and lateral ocelli absent. Median longitudinal, posterolateral, and posterior transverse sulci present, shallow. Surface smooth, shiny, acarinate, with scattered microsetae.

Pedipalps: Femur, dorsoexternal, dorsointernal, ventrointernal, ventroexternal carinae obsolete, granular (fig. 37A). Dorsal and internal surfaces sparsely and coarsely granular; ventral and external surfaces smooth. Patella dorsointernal carina distinct, coarsely granular; dorsoexternal, ventroexternal, and ventrointernal carinae obsolete, costate; internomedian carina comprising only a basal granule; other carinae absent or obsolete (fig. 37B–D). Chela manus broad (fig. 36). Dorsomedian, dorsal secondary, and ventroexternal carinae obsolete, granular; other carinae absent. Manus, intercarinal surfaces smooth proximally, becoming moderately granular medially; internal surface with pair of prominent, isolated granules situated close together at base of fixed finger; fingers smooth. Fixed finger, median denticle row comprising six oblique primary subrows, terminal subrow short, comprising one or two denticles, other subrows similar in length (fig. 9O); terminal denticle of fixed finger similar to preceding denticles, fingertips interlocking evenly when closed. Movable finger, median denticle row comprising six oblique primary subrows, terminal row short, comprising one or two denticles, basal subrow longer than other subrows (fig. 9P).

Trichobothria: Femur with three trichobothria (fig. 37A): one external (e), one dorsal (d), one internal (i). Patella with 19 trichobothria (fig. 37B–D), five petite (d₁, d₂, et₂, esb₂, eb₂), one accessory (em₃): two ventral (v₁, v₂); 14 external (et₁–et₃, est, em₁–em₃, esb₁, esb₂, eb₁–eb₅); two dorsal (d₁, d₂); one internal (i). Chela with 26 trichobothria (fig. 36), seven petite (V₁, Et₄, Et₅, Esb, Db, esb, db): 16 on manus, four ventral (V₁–V₄), 10 external (Et₁–Et₅, Est, Esb, Eb₁–Eb₃), two dorsal (Db, Dt); 10 on fixed finger, four external (et, est, esb, eb), four dorsal (dt, dst, dsb, db), two internal (it, ib).

Legs: All surfaces covered with scattered microsetae; basitarsi with fewer setae than telotarsi. Basitarsi I–IV without prolateral pedal spurs; I and II, proventral surfaces with short subdistal row of closely aligned spinules. Telotarsi, ventral surface with curved row of spinules, proximally, and 6–8 submedian pairs of subspiniform macrosetae; ungues moderately long, equal in length; dactyl moderately developed, slightly curved.

Tergites: Surfaces I–VI smooth, shiny, acarinate (fig. 35A); VII coarsely granular in posterior half, dorsosubmedian and dorsolateral carinae vestigial, reduced to few posterior granules.

Sternum: Posterior width greater than length; apex rounded; lateral margins converging anteriorly; lateral lobes flat; posterior depression shallow. Surface smooth, asetose.

Genital operculum: Sclerites completely divided; genital papillae protruding distinctly beyond posterior edges. Surfaces smooth, shiny, asetose.

Pectines: Pectinal plate, surface with pair of macrosetae. Lamella comprising three segments. Tooth count, 5/5; teeth oval; proximal and distal teeth slightly larger.

Sternites: Surfaces acarinate. Surfaces and margins smooth, shiny, with scattered microsetae. Respiratory spiracles (stigmata) small, round, situated posterolaterally.

Metasoma: Segments stout, progressively increasing in length, decreasing in width (fig. 35B), segment I width greater than length, II width equal to length, III–V length greater than width (table 7). Dorsosubmedian carinae, segments I–IV, obsolete, coarsely and sparsely granular, distal granules not noticeably larger than preceding granules; V, absent. Dorsolateral carinae, segments I–IV, absent to obsolete, smooth; V, obsolete, granular. Median lateral carinae, segments I–V, absent. Ventrolateral carinae, segment I, absent; II–IV, obsolete, smooth; V, obsolete, granular. Ventrosubmedian carinae, segments I–IV, and ventromedian carina, segment V, absent. Dorsal intercarinal surfaces, segments I–V, slightly concave. All segments, intercarinal surfaces smooth, shiny, with scattered macrosetae.

Telson: Vesicle globose, flattened to slightly concave dorsally, rounded ventrally; anterodorsal lateral lobes absent (fig. 35B); surface smooth, with sparse setae ventrally and posteriorly. Aculeus short, sharply curved, arising abruptly from vesicle.

Hemispermatophore: Adult male unknown.

Ontogenetic variation: Adult unknown.

Geographical variation: Single specimen.

Sexual dimorphism: Female unknown.

Remarks

The metasoma of the holotype is separated from the body at the articulation of segments I and II, the left pedipalp chela is crushed, and the posterior margin of the carapace is slightly damaged. Left leg I was removed and retained at the AMCC for DNA isolation, amplification, and sequencing.

Distribution

Known only from the type locality in Queretaro (central Mexico) (fig. 1B).

Ecology

This troglomorphic species was taken from under a stone in a mesophilous forest (Francke et al., 2009). The fact that it was not collected inside a cave, taken together with its similar habitus to the two endogean species, T. mitchelli and T. sylvestris, suggests that it may also be endogean.

Fig. 38

Typhlochactas sylvestris Mitchell and Peck, 1977, holotype ♀ (AMNH), habitus. A. Dorsal aspect. B. Ventral aspect. Scale  =  1 mm.

Fig. 39

Typhlochactas sylvestris Mitchell and Peck, 1977, holotype ♀ (AMNH), sinistral pedipalp chela showing carinae and distribution of trichobothria. A. Dorsal aspect. B. External aspect. C. Ventral aspect. Scale  =  0.1 mm.

Fig. 40

Typhlochactas sylvestris Mitchell and Peck, 1977, holotype ♀ (AMNH), sinistral pedipalp femur (A) and patella (B–D) showing carinae and distribution of trichobothria. A, B. Dorsal aspect. C. External aspect. D. Ventral aspect. Scales  =  0.1 mm.

Type material

Mexico: Oaxaca: Município de Valle Nacional: Holotype: 1 ♀ (AMNH), Valle Nacional, 25 km S along Highway 175 (Oaxaca–Tuxtepec) [17°36′43″N 96°25′09″W], 1200 m, S.B. Peck, 21.V.1971, Berlese sample #204.

Diagnosis

Typhlochactas sylvestris is most closely related to T. mitchelli (fig. 4). It may be separated from T. mitchelli and all other Typhlochactas species by the following combination of characters. Cheliceral fixed finger with three teeth (subdistal absent); median and basal teeth not fused into bicusp. Cheliceral movable finger with four dorsal teeth (one subdistal present). Carapace, anterior margin with well-developed median projection (epistome). Pedipalp chela fixed and movable fingers, median denticle row comprising five and six oblique primary subrows, respectively; basal primary subrow of movable finger similar in length to other subrows; terminal denticle of fixed finger slightly larger than preceding denticles, fingertips interlocking evenly when closed. Legs with prolateral pedal spurs. Telotarsi with ventromedian row of spinules. Sclerites of genital operculum (♀) completely fused, no suture evident.

Description

The following description of the holotype (fig. 38) supplements the original description by Mitchell and Peck (1977) and supplementary data provided by Francke (1982a, 1986).

Color: Holotype uniformly Kingfisher Rufous (240).

Chelicerae: Manus, dorsal and ventral surfaces smooth; dorsal surface with few microsetae, one on movable finger. Fixed finger, dorsal margin with three teeth (distal, median and basal; fig. 5I); median and basal teeth equal, not fused into bicusp, considerably smaller than distal tooth. Movable finger, internal distal and external distal teeth not opposable, internal distal tooth at most partially overlapping external distal tooth in dorsal view; dorsal margin of dextral chelicera with four teeth (internal distal, subdistal, median and basal), of sinistral chelicera with three teeth (basal tooth absent), subdistal, median and basal teeth very small, equal, situated very close together, forming a compound tooth, three-quarters along finger, internal distal tooth considerably larger; ventral surface with long serrula occupying four-fifths of finger, covered in part by dense brush of macrosetae.

Carapace: Length greater than anterior width (table 9). Anterior margin sublinear, with small median projection (epistome); asetose (fig. 38A). Posterior margin weakly concave medially; asetose. Median and lateral ocelli absent. Median longitudinal, posterolateral, and posterior transverse sulci shallow. Surface smooth, acarinate, with scattered microsetae.

Pedipalps: Femur, ventroexternal carina obsolete, granular; other carinae absent (fig. 40A). Dorsal and internal surfaces with few granules and short, sparse setae. Patella acarinate (fig. 40B–D); all surfaces smooth. Chela stout, with broad, rounded manus and short fingers (table 9). Manus acarinate (fig. 39); surfaces of manus, fixed and movable fingers smooth, with short microsetae. Fixed finger, median denticle row comprising five oblique primary subrows, similar in length (fig. 9Q); terminal denticle small, slightly larger than preceding denticles, fingertips interlocking evenly when closed. Movable finger, median denticle row comprising six oblique primary subrows; all subrows similar in length, but terminal and basal subrows slightly shorter (fig. 9R); terminal denticle small.

Trichobothria: Femur with three trichobothria (fig. 40A): one external (e), one dorsal (d), one internal (i). Patella with 19 or 20 trichobothria (fig. 40B–D), six petite (d₁, d₂, et₂, esb₂, eb₂, v₃), two accessory (em₃, v₃ dextral only): two ventral (v₁, v₂); 14 (sinistral) or 15 (dextral) external (et₁–et₃, est, em₁–em₃, esb₁, esb₂, eb₁–eb₅, v₃ dextral only); two dorsal (d₁, d₂); one internal (i). Chela with 26 trichobothria (fig. 39), seven petite (V₁, Et₄, Et₅, Esb, Db, esb, db): 16 on manus, four ventral (V₁–V₄), 10 external (Et₁–Et₅, Est, Esb, Eb₁–Eb₃), two dorsal (Db, Dt); 10 on fixed finger, four external (et, est, esb, eb), four dorsal (dt, dst, dsb, db), two internal (it, ib). The designations of et₃ and v₃ used in this paper follow the fourth interpretation proposed by Prendini and Wheeler (2005: 470), according to which these trichobothria correspond, respectively, to Mitchell and Peck's (1977, 163: fig. 12) et₃ and sn, rather than the third interpretation, favored by Prendini and Wheeler (2005: 469, figs. 22, 23).

Legs: All surfaces setose. Basitarsi I–IV with prolateral pedal spurs; I and II, proventral surfaces with short subdistal row of closely aligned spinules. Telotarsi, dorsomedian lobe with one microseta; ventral surface with curved row of spinules, proximally, and straight ventromedian row of spinules, flanked by three or four submedian pairs of subspiniform macrosetae; ungues short, equal in length, weakly curved; dactyl short, robust.

Tergites: Surfaces acarinate. Surfaces and margins smooth, with few microsetae (fig. 38A).

Sternum: Posterior width greater than length; apex rounded (fig. 8D); lateral margins subparallel; lateral lobes flat; posterior depression very shallow. Surface with eight macrosetae.

Genital operculum: Sclerites completely fused, no suture evident (fig. 8D); anterior margin slightly concave; posterior margin convex. Surfaces almost asetose.

Pectines: Pectinal plate, surface with two macrosetae situated mediolaterally. Lamella comprising five segments (fig. 8D). Tooth count, 5/5; teeth pointed; proximal and distal teeth slightly larger.

Sternites: Surfaces acarinate (fig. 38B). Surfaces and margins smooth, with scattered microsetae. Respiratory spiracles (stigmata) small, round, situated posterolaterally.

Metasoma: Metasoma stout, segments progressively increasing in length, decreasing in width (fig. 12G), I–III width greater than length, IV width equal to length, V length greater than width (table 9). Dorsosubmedian carinae, segments I–IV, obsolete, granular, distal granules not noticeably larger than preceding granules. Dorsolateral carinae, segment V, obsolete, comprising few granules in posterior part of segment. Dorsolateral, median lateral and ventrosubmedian carinae, segments I–IV, ventrolateral carinae, segments I–V, and ventromedian carina, segment V, absent. Dorsal intercarinal surfaces, segments I–V, slightly concave. Intercarinal surfaces smooth, shiny, setose.

Telson: Vesicle globose, flattened to slightly concave dorsally, rounded ventrally; anterodorsal lateral lobes absent (fig. 12G); surface smooth, with several long and short setae posteriorly. Aculeus short, sharply curved, arising abruptly from vesicle.

Hemispermatophore: Male unknown.

Ontogenetic variation: Juvenile and subadult unknown.

Geographical variation: Single specimen.

Sexual dimorphism: Male unknown.

Remarks

Mitchell and Peck (1977) listed the Museum of Texas Tech University as depository. The specimen has since been transferred to the AMNH (Sissom, 2000b). The holotype is severely damaged (fig. 38): the mesosoma is broken and the dextral chelicera, movable finger of the sinistral pedipalp chela, and part of sinistral leg IV are lost.

Distribution

Known only from the type locality, a mixed-species cloud forest with a dominant oak component, in the Sistema Montañoso Poblano Oaxaqueño, Oaxaca (southern Mexico) (fig. 1B).

Ecology

This endogean (humicolous) species was extracted, using metal “Tulgren” Berlese funnels, from 27 l of forest litter collected and pooled from two sites at the type locality. For more details, see Mitchell and Peck (1977).