Centrurus (nec Ehrenberg, 1829): Thorell, 1876a: 9; 1876b: 83; Karsch, 1879a: 18; Pocock, 1890: 120, 121, 127; Kraepelin, 1891: 119–124 (part); Pocock, 1893: 375, 385, 386; Laurie, 1896: 131; Lönnberg, 1897: 196, 197, 208; Kraepelin, 1899: 87 (part); Banks, 1900: 425; Borelli, 1909: 222; Comstock, 1912: 25, 27, fig. 31; Birula, 1917a: 164; 1917b: 54, 107; Ochoterena, 1920: 223; Mello-Campos, 1924a: 246; 1924b: 312; Comstock, 1940: 27, fig. 31 (lapsus calami); Millot and Vachon, 1949: 427; Díaz Nájera, 1966: 110, 111, pl. 1; 1970: 113.

Centruro: Karsch, 1879b: 120 (lapsus calami).

Centruroides Marx, 1890: 211, type species Buthus exilicauda Wood, 1863 (= Centruroides exilicauda (Wood, 1863), by monotypy; Pocock, 1902a: 19, 20; 1902b: 365; Kraepelin, 1912: 69–71; 1914: 22; Hoffmann, 1932: 244, 245; Mello-Leitão, 1932: 27; 1934: 4, 5; Franganillo, 1936: 158; Hoffmann, 1937: 201–203; Moreno, 1939: 63; Comstock, 1940: 25, 27; Moreno, 1940: 164; Mello-Leitão, 1942: 126; 1945: 240, 250–252; Scorza, 1954:190; Bücherl, 1964: 59; 1967: 113; Muma, 1967: 2, 4; Bücherl, 1969: 767; Aguilar and Meneses, 1970: 3; Bücherl, 1971: 327; Stahnke, 1971: 282; 1972: 125, fig. 9; Armas, 1974a: 25; Vachon, 1974: 906, 908; 1975: 1598; Francke, 1977: 75; Stahnke and Calos, 1977: 111; Vachon, 1977: 294; Lourenço, 1979: 214; Williams, 1980: 2, 4; Armas, 1984: 2; González-Sponga, 1984: 64, 65; Francke, 1985: 7, 15; Francke and Stockwell, 1987: 7; Armas, 1988: 44, 91, 95; Stockwell, 1988: 3; Sissom, 1990: 94, 101; Nenilin and Fet, 1992: 9, 12–14; Stockwell, 1992: 412, 419; González-Sponga, 1996: 118, 119, 124, 125, figs. 285–287, 289, 292; Armas, 1998: 50; Kovařík, 1998: 106; Fet and Lowe, 2000: 98–122; Towler et al., 2001: 161–163; Armas et al., 2004: 167–171, tables 1–3; Prendini and Wheeler, 2005: 481, table 10; Kamenz and Prendini, 2008: 6, 8, 22, 40, tables 1, 2, pl. 13–17; Volschenk et al., 2008: 654, 656, 658, 659, 663, 664, 674, fig. 1C, tables 1, 2; Armas et al., 2012: 106, 112; Cupitra Vergara et al., 2014: 207–215, figs. 1–4, tables 1, 2; Kovařík and Teruel, 2014: 1, 7, 15, 25, 26; Loria and Prendini, 2014: 3, 9, 10, 24, 25, fig. 2D, table 5; Lourenço, 2014: 60, 63; Miller et al., 2014: 301, 306, 307, table 1; Ponce-Saavedra and Francke, 2014: 54, figs. 11, 14; Quintero Arias and Esposito, 2014: 373–382, figs. 1–6, table 1; Teruel and Rodríguez-Cabrera, 2014: 131; Armas and Ávila, 2015: 66, 67, 69, 70, 71; Ponce-Saavedra et al., 2015: 81–89, figs. 1–5, tables 1, 2; Quijano-Ravell and Ponce-Saavedra, 2015: 35–44, figs. 1–5, tables 1–3; Riquelme et al., 2015: 2, 16, 18, 19; Teruel et al., 2015a: 3–14, figs. 1–37, table 1; 2015b: 1–18, figs. 1–35, tables 1–5; 2015c: 13–33, figs. 1–75, tables 1–4; Baldazo-Monsivaiz et al., 2016: 76–79, fig. 2A, table 1; de los Santos et al., 2016: 1–7, 14, 16–19, 22, figs. 2A–G, 3A, table 1; Kovařík et al., 2016a: 1, 11, 18, 19; Lourenço and Velten, 2016: 61, 65; Quijano-Ravell and Ponce-Saavedra, 2016a: 49–61, figs. 1–9, tables 1–4; 2016b: 85–90, figs. 1–4; Teruel, 2016: 91–93, figs. 1–3; Baldazo-Monsivaiz, 2017: 21–27, fig. 2A; Esposito et al., 2017: 2–15, 29, 30, 35–37, 41, 61, 71, 81, 85, 101, 116, 122, 124, 126, 128–130, fig. 13; McWest et al., 2015: 3, 9, 10, 25, 28, 30–34, 38, figs. 2A, 3A, 4A; Teruel and Myers, 2017: 1–14, figs. 1–11, table 1; Teruel et al., 2017: 6; Ubinski et al., 2018: 475–486, figs. 1–8, tables 1, 2; Esposito and Prendini, 2019: 1–10, figs. 1, 2, 3, tables 1–4; Crews and Esposito, 2020: 8, 9, 12, 17, 18; Fet and Kovařík, 2020: 8, 10, 12, 14, 18, 19, 22–26, 28, 29, 31; Howard et al., 2019: 74, 84, fig. 3, table 1; Miranda and Armas, 2020: 5, 7; Ponce-Saavedra and Francke, 2019: 1–17, figs. 1–11, tables 1–4; Quijano-Ravell et al., 2019: 31–48, figs. 1–32, tables 1–5; Teruel and Questel, 2020: 12, 14; Trujillo and Armas, 2020: 1–8, figs. 1–4, table 1; Wendruff et al., 2020: 2, 5, 6, fig. 2B.

Centruroides (Centruroides): Werner, 1934: 273.

Centruoroides: Díaz Nájera, 1970: 117 (lapsus calami).

Centruriodes: Lourenço and Eickstedt, 1988: 7 (lapsus calami).

Centruroides schmidti: Sissom, 1995: 94–96; figs. 10–18, table 1 (misidentification: paratypes from Escobas, Izabal, Guatemala).

Type Material: GUATEMALA: Departamento Izabal: Município Livingston: Holotype ♂(CASENT 9073325), paratype ♂ (CASENT 9073298), Río Dulce, Hotel Tijax, 15°39′51.2″N 89°00′14.6″W, 17 m, 24.ix.2019, A.M. Goodman, collected along gravel road of Hacienda Tijax Parking Lot, flanked by bamboo groves, and live fencing; 2 ♂ paratypes (CASENT 9073312, 9073326), 4 ♀ paratypes (CASENT 9073297, 9073313, 9073324, 9073368), Biotopo Chocón Machacas, 15°44′05.3″N 88°54′57.2″W, 15 m, 25.ix.2019, A.M. Goodman.

Etymology: The species name is a patronym honoring the late Hyman Maxwell Berston, the first author's grandfather (1930–2021), who inspired his interest in natural history during childhood visits to the California Academy of Sciences.

Diagnosis: Centruroides berstoni is most closely related to C. hamadryas, from which it differs as follows. The carapace is sparsely granular, more densely so on the interocular triangle, in the female of C. berstoni but densely granular, with distinct lateral ocular carinae, in the female of C. hamadryas (fig. 6B, D). The pedipalp chela manus of the male is proportionally less incrassate in C. berstoni (figs. 13–15B) than C. hamadryas (fig. 13–15A, tables 4, 5). The retrodorsal carina of the chela manus is weakly granular and the dorsomedian carina absent in the male of C. berstoni (fig. 13B), whereas the retrodorsal carina is complete and the dorsomedian carina weakly developed and restricted to the distal half in the male of C. hamadryas (fig. 13A). The retrodorsal carina of the manus is finely granular and the prodorsal carina absent in the female of C. berstoni (fig. 14B), whereas the retrodorsal carina is complete and the prodorsal carina restricted to the distal third in the female of C. hamadryas (fig. 14A). The first leg of the male is greater than 2× the length of the carapace in C. berstoni but less than 2× its length in C. hamadryas (table 10). The dorsomedian carinae of the mesosomal tergites are weakly developed and restricted to the posterior half in C. berstoni but distinct and complete in C. hamadryas. The ventrolateral carinae of mesosomal sternite VII are weakly developed and the ventrosubmedian carinae absent in C. berstoni, whereas the ventrolateral and ventrosubmedian carinae are weakly developed to absent in C. hamadryas. The telson vesicle is sparsely setose in C. berstoni (figs. 23H, K, 24H, K, 25H, K), but densely setose in C. hamadryas (figs. 23B, E, 24B, E, 25B, E).

Additional differences between C. berstoni and other species of the clade are as follows. The ventrosubmedian and ventrolateral carinae of metasomal segments I–IV in the male are weakly developed, smooth in C. berstoni (figs. 18H, 19H) but absent in C. catemacoensis (figs. 18, 19M), well developed in C. cuauhmapan (figs. 18, 19G), weakly developed on segments I–III, absent on IV in C. hamadryas (figs. 18–19B, 21–22B), and vestigial, smooth in C. rileyi (figs. 18, 19A, 21–22A). The metasomal carinae of the female are finely granular in C. berstoni (figs. 17–22K) but well developed, granular in C. catemacoensis (figs. 17–22P). The telson vesicle is short and not posteriorly bilobed in the male of C. berstoni (figs. 23–25H), unlike in C. cuauhmapan (figs. 23–25G) and C. rileyi (figs 23–25A), and with surfaces sparsely granular in the female of C. berstoni (figs. 23–25K), but smooth in the female of C. hamadryas (figs. 23–25E) and densely granular in the female of C. catemacoensis (figs. 23–25P), C. cuauhmapan (figs. 23–25J), and C. rileyi (figs. 23–25D).

Description: The following description is based on the holotype male, with differences among other material noted in the section on variation.

Coloration: Base color pale yellow, with extensive infuscation, creating mottled or marbled pattern. Carapace with uniformly infuscate marbling, more densely infuscate medially. Pedipalp chela fingers and manus, dorsal and retrolateral intercarinal surfaces with moderately infuscate marbling; prolateral and ventral intercarinal surfaces mostly immaculate. Legs retrolateral surfaces with infuscate marbling; prolateral surfaces pale, immaculate. Tergites with unformly infuscate mottling, pale stripe medially, blackish spots submedially, and faint, narrow bands laterally. Sternites pale, with faintly infuscate triangular to trapezoidal marking at posterior margin of III, fading to infuscate mottling on VII. Metasomal segments uniformly, faintly marbled; segment V and telson markedly infuscate, noticeably darker than preceding segments.

Carapace: Shape trapezoidal; anterior width four-fifths of posterior width (table 5); anteromedian sulcus moderately deep, oval; posteromedian sulcus shallow anteriorly, deeper posteriorly; median ocular tubercle weakly granular; carinae moderately developed, comprising small to medium-sized granules (fig. 6C).

Pedipalps: Orthobothriotaxic, Type A; femur dorsal trichobothria with α configuration; pedipalp chela fixed finger, trichobothrium db situated slightly distal to et. Femoral carinae serrate; retromedian carinae comprising spiniform granules; dorsal intercarinal surface moderately granular; prolateral intercarinal surface with series of large spiniform granules. Patella carinae strongly developed, granular; prolateral intercarinal surface with five or six large, subspiniform granules. Chela manus prodorsal and dorsomedian carinae absent; retrodorsal carina weakly developed, granular. Fixed finger, median denticle row comprising eight oblique subrows, each flanked by pro- and retrolateral supernumerary denticles. Movable finger, median denticle row with short terminal row comprising four denticles preceded by eight oblique subrows, each flanked by pro- and retrolateral supernumerary denticles.

Legs: Leg I length 2× carapace length (table 10). Telotarsi ventral surfaces densely covered with short setae; ungues markedly curved.

Pectines: Pectinal plate 1.65× wider than long; posterior margin distinctly rounded; pectinal tooth count 16/15 (♂) (fig. 9C, table 5).

Mesosoma: Tergites width similar to carapace posterior width; I and II slightly narrower (table 5). Pretergites surfaces smooth to finely granular. Posttergites surfaces weakly granular; I–VI with dorsomedian carinae weakly granular, restricted to posterior half of each segment; VII surface weakly granular, dorsomedian carinae moderately granular, dorsosubmedian carinae weakly granular, dorsolateral carinae absent. Sternites III–VI, surfaces smooth; VII surface smooth, ventrolateral carinae reduced to few granules.

Metasoma: Metasoma length 3.23× mesosoma length (table 10). Segments longer than wide; increasing in length posteriorly, segment V 2× length of I; carinae weakly developed, smooth on segments I–IV (figs. 17–21H), absent or obsolete on V (figs. 20–22H); intercarinal surfaces sparsely granular.

Telson: Vesicle elongate, ovoid; ventral surface shallowly convex; subaculear tubercle narrow and angular in lateral aspect, directed toward midpoint of aculeus. Aculeus angled ventrally at slightly less than 90° (figs. 23–25H).

Variation: Base color varies from pale yellow to light orange with considerable variation in infuscation of the carapace and mesosoma, despite localities being less than 50 km apart. Adult males and females differ as follows. The mesosoma is proportionally longer and slenderer, the metasoma up to 3× longer, with segment V markedly longer, and the telson more elongate, with the vesicle more rounded and bilobed posteriorly, in males (figs. 20H, K, 21H, K, 22H, K, table 5). The tegument is more densely infuscate, the pectinal plate produced into a rounded lobe posteriorly, which is punctate and slightly infuscate, and the telson shorter and narrower with the vesicle surfaces less granular, in females (figs. 9C, D, 23H, K, 24H, K, 25H, K, 34–35A, B).

Distribution: Centruroides berstoni is endemic to the Izabal Department of Guatemala and has been recorded from several localities around Morales and Río Dulce (figs. 1B, D, 4).

Ecology: The localities at which C. berstoni was recorded range in altitude from 15–17 m and occur in a region of humid tropical lowland rainforest. Specimens were collected at night with UV light detection, mostly on trees, sitting on bark or branches, and large shoots of bamboo. The habitat and habitus are consistent with the arboreal, corticolous ecomorphotype (Prendini, 2001a).

Remarks: The paratype female of C. schmidti, from Morales, Guatemala, was misidentified by Sissom (1995). Differences between the paratype and other females that species, evident from the illustrations (Sissom, 1995: 94–95 figs. 16–18), include faint reticulate infuscation on the chelicerae, less infuscation of the carapace and tergites, less granulation and setation of the metasomal segments, and a bilobed telson vesicle.

Material Examined: GUATEMALA: Departamento Izabal: Município Livingston: Biotopo Chocón Machacas, 15°44′05.3″N 88°54′57.2″W, 15 m, 25.ix.2019, A.M. Goodman, 8 ♂, 1 ♀, 1 juv. ♂ (CASENT 9073271); Río Dulce, Hotel Tijax, 15°40′12.2″N 89°00′27″W, 49 m, 8.vii.2006, J. Huff, C. Víquez, and D. Ortíz, collected along trails through old secondary growth tropical forest using UV at night, 1 ♂ (AMNH [LP 5984]), 15°39′51.2″N 89°00′14.6″W, 17 m, 24.ix.2019, A.M. Goodman, collected along gravel road of Hacienda Tijax Parking Lot, flanked by bamboo groves and live fencing, 1 ♂ (CASENT 9073272), 15°44′05.3″N 88°54′57.2″W, 15 m, 25.ix.2019, A.M. Goodman, 8 ♂, 1 ♀, 1 juv. ♂ (CASENT 9073271). Município Morales: Morales, Finca Fiymeza, Sendero Anfibio, 15°24′24.1″N 88°41′46.8″W, 595 m, 17.viii.2017, D. Barrales and R. Monjaraz, 1 juv. ♀ (CNAN SC3968).

Type Material: MEXICO: Veracruz: Município Catemaco: Holotype ♂ (CNAN T01424), 4 ♂ paratypes (CASENT 9073286, 9073287, 9073366, CNAN T01421), 4 ♀ paratypes (CASENT 9073309, 9073314, CNAN T01422, T01423), Estacion Biología Los Tuxtlas, Universidad Nacional Autónoma de México (UNAM), 18°34′54″N 95°04′54.6″W, 74–416 m, 17.vii–25.vii.2018, A.M. Goodman, J. Gorneau, and M.K. Lippey; paratype ♂ (CNAN T01420), Estacion Biología Los Tuxtlas, UNAM, Cerro El Vigia Reserva de la Biosfera Los Tuxtlas, 18°34′47.9″N 95°04′29.2″W, 421–429 m, 27. vii.2005, O.F. Francke, M. Cordóva, A. Jaimes, A. Valdez, and H. Montaño.

Etymology: The species name refers to the town of Catemaco, nearby the type locality, in the state of Veracruz, Mexico.

Diagnosis: Centruroides catemacoensis differs from the closely related species, C. berstoni, C. cuauhmapan, C. hamadryas, and C. rileyi as follows. The base coloration of C. catemacoensis varies from dark yellow to orange, with considerable infuscation on the pedipalps and metasoma whereas the base coloration of C. berstoni, C. cuauhmapan, and C. hamadryas is pale yellow and of C. rileyi, yellowish orange. The carapace posterosubmedian carinae are reduced or absent in C. catemacoensis (fig. 5E, F), absent in C. berstoni (fig. 6C, D), C. cuauhmapan (fig. 5C, D), and C. hamadryas (fig. 6A, B), and present in C. rileyi (fig. 5A, B). The pedipalps are longer, and the chela manus dorsoventrally compressed, in the male, whereas the manus is shorter and slenderer in the female of C. catemacoensis than the other species (fig. 11C). Additionally, the chela movable finger is 2.5–3× (male) or 2.5× (female) the length of the manus in C. catemacoensis (figs. 11, 12C, table 6) but 1.5–1.7× (male) or 1.3× (female) the length of the manus in C. berstoni (figs. 13, 14B, table 5), C. cuauhmapan (figs. 11, 12B, table 3), C. hamadryas (figs. 13, 14A, table 4), and C. rileyi (figs. 11, 12A, table 2). The pedipalp chela manus is two-thirds the length of the patella in C. catemacoensis (figs. 11, 12C, table 6), but half its length in C. berstoni (figs. 13, 14B, table 5), C. cuauhmapan (figs. 11, 12B, table 3), C. hamadryas (figs. 13, 14A, table 4), and C. rileyi (figs. 11, 12A table 2). The prodorsal carina is restricted to the distal half of the chela manus in C. catemacoensis (figs. 11, 12C), whereas it is complete in C. cuauhmapan (figs. 11, 12B), C. hamadryas (figs. 13, 14A), and C. rileyi (figs. 11, 12A) and absent in C. chanae (figs. 15, 16B) and C. yucatanensis (figs. 15, 16C). The first leg is less than 2× the length of the carapace in the male of C. catemacoensis but greater than 2× its length in C. cuauhmapan, C. hamadryas, and C. rileyi (table 10). The ventrosubmedian and ventrolateral carinae of sternite VII of the male are weakly developed in C. catemacoensis but well developed, granular in C. cuauhmapan and obsolete to absent in C. berstoni and C. rileyi. The metasoma of the male is greater than 3× the length of the mesosoma in C. cuauhmapan but less than 3× its length in C. berstoni, C. hamadryas, and C. rileyi (table 10). The ventrolateral and ventrosubmedian carinae of metasomal segments I–IV in the male are absent in C. catemacoensis (figs. 18, 19M), weakly developed, smooth in C. berstoni (figs. 18H, K, 19H, K, 21H, K, 22H, K), well developed in C. cuauhmapan (figs. 18G, J, 19G, J, 21G, J, 22G, J), weakly developed on segments I–III and absent on IV in C. hamadryas (figs. 18B, E, 19B, E), and vestigial, smooth in C. rileyi (figs. 18A, D, 19A, D). The metasomal carinae of the female are well developed, granular in C. catemacoensis (figs. 17–22P), but finely granular in C. berstoni (figs. 17–22K), C. cuauhmapan (figs. 17–22J), C. hamadryas (figs. 17–22E), and C. rileyi (figs. 17–22D).

Description: The following description is based on the holotype male, with differences among other material noted in the section on variation.

Coloration: Base color yellow to orange, with extensive infuscation, creating mottled or marbled pattern. Carapace with uniformly infuscate marbling, more densely infuscate medially. Pedipalp chela fingers and manus, dorsal and retrolateral intercarinal surfaces with moderately infuscate marbling; prolateral and ventral intercarinal surfaces mostly immaculate. Legs retrolateral surfaces with infuscate marbling; prolateral surfaces pale, immaculate. Tergites with unformly infuscate mottling, pale stripe medially, blackish spots submedially, and distinct, narrow bands laterally. Sternites moderately infuscate, with faintly infuscate triangular marking at posterior margin of III, fading to infuscate mottling on VII. Metasomal segments uniformly, faintly marbled; segment V and telson markedly infuscate, noticeably darker than preceding segments.

Carapace: Shape trapezoidal; anterior width four-fifths of posterior width (table 6); anteromedian sulcus moderately deep, narrow; posteromedian sulcus shallow anteriorly, deep, narrow posteriorly; carinae moderately developed, comprising small to medium-sized granules (fig. 5E).

Pedipalps: Orthobothriotaxic, Type A; femur dorsal trichobothria with α configuration; pedipalp chela fixed finger, trichobothrium db situated slightly distal to et. Femoral carinae moderately to strongly developed, serrate; retromedian carinae comprising spiniform granules; dorsal intercarinal surface moderately granular; prolateral intercarinal surface with series of large spiniform granules. Patella dorsomedian, retrodorsal, prodorsal, and proventral carinae moderately developed, serrate; retromedian carina strongly developed, serrate; retroventral carina incomplete, serrate; prolateral intercarinal surface with five or six large, subspiniform granules. Chela manus proventral carina moderately developed, comprising few rounded granules; other carinae weakly developed, granular. Fixed finger, median denticle row comprising eight oblique subrows, each flanked by pro- and retrolateral supernumerary denticles. Movable finger, median denticle row with short terminal row comprising four denticles preceded by eight oblique subrows, each flanked by pro- and retrolateral supernumerary denticles.

Legs: Leg I length 1.94× greater than carapace length (table 10). Telotarsi ventral surfaces densely covered with short setae; ungues markedly curved.

Pectines: Pectinal plate 1.9× wider than long; posterior margin distinctly rounded; pectinal tooth count 14/14 (♂) (fig. 8E, table 6).

Mesosoma: Tergites width similar to carapace posterior width; I and II slightly narrower (table 6). Pretergites surfaces smooth to finely granular. Posttergites surfaces weakly granular; I–VI with dorsomedian carinae vestigial, reduced to several small granules; VII surface weakly granular, dorsomedian carina vestigial, reduced to several small granules, dorsosubmedian and dorsolateral carinae finely serrate. Sternites III–VI, surfaces smooth; VII surface weakly granular, ventrolateral carinae serrate.

Metasoma: Metasoma length 2.83× mesosoma length (table 6). Segments longer than wide; increasing in length posteriorly, segment V 2× length of I; dorsolateral and dorsosubmedian carinae weakly serrate on segments I–III, other carinae absent or obsolete; intercarinal surfaces sparsely granular (figs. 17–22M).

Telson: Vesicle elongate, ovoid, length 1.5× width (table 6); ventral surface shallowly convex; ventromedian carina granular, terminating at subaculear tubercle; subaculear tubercle narrow and angular in lateral aspect, directed toward midpoint of aculeus. Aculeus angled ventrally at slightly less than 90° (fig. 25M).

Variation: Base coloration varies from light yellow to orange with considerable variation in infuscation of the carapace and mesosoma (figs. 30, 31A, B). Adult males and females differ as follows. The mesosoma is proportionally longer and slenderer, the metasoma up to 3× longer, with segment V markedly longer, and the telson more elongate, with the vesicle more rounded and bilobed posteriorly, in males (figs. 17–22M, table 6). The tegument is more densely infuscate, the pectinal plate is produced into a rounded lobe posteriorly, which is punctate and slightly infuscate, and the telson is shorter and narrower, with the vesicle surfaces less granular, in females (figs. 23–25P). The pectinal tooth count is similar in both sexes (fig. 8E, F, table 6).

Distribution: Centruroides catemacoensis is endemic to the Los Tuxtlas Biosphere Reserve in the state of Veracruz, eastern Mexico. Most of the known material was collected in the vicinity of the Estación Biologica Los Tuxtlas, UNAM (fig. 3).

Ecology: The localities at which C. catemacoensis has been recorded range in altitude from 74 to 493, in an area of tropical moist broadleaf forest, dominated by thorny palms, Astrocaryum mexicanum Leibm. (Arecaceae Berch and J. Presl,), and buttress trees including Siparuna andina Tul. (Sipuranaceae A. DC). and Vochysia guatemalensis Donn. Sm. (Vochysiaceae A. St.-Hil). This arboreal scorpion has been collected from 3 to 15 m above ground in the forest canopy, often in bromeliads, Aechmea bracteata Grisebach (Bromeliaceae Juss). A few individuals were collected in the leaf litter. The habitat and habitus are consistent with the arboreal, corticolous ecomorphotype (Prendini, 2001a).

Material Examined: MEXICO: Veracruz: Município Catemaco: Estacion Biología Los Tuxtlas, UNAM, 18°35′05.6″N 95°04′29.9″W, 162 m, 27.vi.1968, C.R.B., in A. bracteata at 15 m, 2 ♂, 1 ♀ (CNAN SC3975), 25.i.1969, C.R.B., 15 m above ground in A. bracteata, 1 ♀, 1 juv. ♀ (CNAN SC3976), 22.v.1969, C.R.B., A. bracteata at 12 m, 1 juv. ♂ (CNAN SC3972), 14. vi.1969, C.R.B., in A. bracteata at 10 m, 1 ♂(CNAN SC3974), 15.viii.1997, G. Pérez II, 1 ♂(CNAN SC3971), 134 m, 18.iii.1998, D.E. González Manuel, habitación, 1 ♀ (CNAN SC3969), 162 m, 16.iv.1998, in leaf litter, 1 ♀, 2 juv. ♀ (CNAN SC3970), iii.2001, M. López, 15 m above ground in A. bracteata, 1 ♀ (CNAN SC3977), 134 m, 26.viii.2005. O.F. Francke, M. Córdova, A. Jaimes, A. Valdez, and H. Montaño, 1 ♂ (AMNH [LP 5231]), 18°34′54″N 95°04′54.6″W, 134 m, 19.vii.2002, J. Ponce and O.F. Francke, 1 ♀ (AMNH [LP 2070]), 74–416 m, 17.vii–25.vii.2018, A.M. Goodman, J. Gorneau, and M.K. Lippey, 2 ♂ (CASENT 9073270, 9073427), 2 juv. ♂ (CASENT 9073315, 9073409), 4 juv. ♀ (CASENT 9073408, 9073410, 9073426, 9073428); surroundings of Estacion Biología, Reserva de la Biosfera Los Tuxtlas, 18°30′03.5″N 95°04′29.5″W, 134–493 m, 26.viii.2005, O.F. Francke, M. Cordova, A. Jaimes, A. Valdez, H. Montaño, 2 ♀, 1 juv. ♀(CNAN SC3973).

Type Material: MEXICO: Guerrero: Município Copala: Holotype ♂ (CNAN T01407), Microondas Fogos, 16°33′59.5″N 98°53′18.1″W, 14 m, 2.xi.2007, O.F. Francke, H. Montaño, and A. Ballesteros; 2 ♂ paratypes (CNAN T01403, T01404), 2 ♀ paratypes (CNAN T01405, T01406), same data except: 103 m, 22.vi.2007, O.F. Francke, M. Escalante, H. Montaño, and J. Ballesteros.

Etymology: The species name honors Kendra Chan, a friend of the first author, who passed away in 2018.

Diagnosis: Centruroides chanae is most closely related to C. hoffmanni, from which it differs as follows. A dark line along the lateral margins of the carapace and mesosomal tergites I–III, and pale stripe medially on the carapace and tergites, present in C. chanae, are absent in C. hoffmanni (fig. 7A, D). The carapace, pedipalps, tergites, and metasoma are less infuscate, creating a less mottled appearance, in C. chanae than C. hoffmanni. More reticulate infuscation is present on the chelicerae of C. chanae than those of C. hoffmanni. The interocular triangle is less darkly infuscate in C. chanae than C. hoffmanni. The marbled infuscation of the mesosomal sternites is faint or absent in C. chanae but pronounced in C. hoffmanni. The carapace is shorter, its length and width similar, in C. chanae, but longer, its length greater than its width, in C. hoffmanni. The carapace surfaces are more finely granular, the carinae less developed and the sulci broader and shallower in C. chanae than C. hoffmanni. The pedipalp chela manus of the male is less incrassate in C. chanae (figs. 15, 16A) than C. hoffmanni (figs. 15, 16B). The ventral surfaces of the telotarsi of leg I are more coarsely and densely setose in C. chanae than C. hoffmanni. The pectinal tooth count of the male is higher in C. chanae, usually 17 (fig. 10A) than C. hoffmanni, usually 15 (fig. 10C, tables 8, 9). The ventrolateral carinae of mesosomal sternite VII are distinct, granular and the ventrosubmedian carinae weakly developed, granular in C. chanae, whereas the ventrolateral carinae are granular, and the ventrosubmedian carinae weakly granular and restricted to the posterior half of the segment in C. hoffmanni. Although the metasomal segments of the male are shorter and broader in C. chanae than C. hoffmanni, the metasoma is more than 3× (up to 3.3×) the length of the mesosoma in C. chanae, but less than 3× its length in C. hoffmanni (table 10). The ventrolateral and ventrosubmedian carinae of metasomal segments I–IV are less pronounced in C. chanae, being finely granular to subserrate on I–III and obsolete, smooth on IV (figs. 18I, L, 19I, L), compared with slightly serrate on I–IV in C. hoffmanni (fig. 18C, F, 19C, F). The ventrosubmedian carinae of metasomal segments I and II are absent or obsolete in C. chanae but very pronounced in C. hoffmanni. The telson of the male is shorter, the vesicle rounded posteriorly, in C. chanae (figs. 23–25I) whereas the telson is elongate and the vesicle bilobed posteriorly in C. hoffmanni (figs. 23–25C).

Description: The following description is based on the holotype male, with differences among other material noted in the section on variation.

Coloration: Base color light yellow, with extensive infuscation, creating mottled or marbled pattern. Carapace with uniformly infuscate marbling, more densely infuscate medially. Pedipalp chela fingers and manus, dorsal and retrolateral intercarinal surfaces with moderately infuscate marbling; prolateral and ventral intercarinal surfaces mostly immaculate. Legs retrolateral surfaces with infuscate marbling; prolateral surfaces pale, immaculate. Tergites with unformly infuscate mottling, pale stripe medially, blackish spots submedially, and faint, narrow bands laterally. Sternites pale, mostly immaculate. Metasomal segments uniformly marbled; segment V and telson markedly infuscate, noticeably darker than preceding segments.

Carapace: Shape trapezoidal; anterior width four-fifths of posterior width (table 9); anteromedian sulcus moderately deep, oval; posteromedian sulcus shallow anteriorly, deep posteriorly; median ocular tubercle weakly granular; carinae moderately developed, comprising small to medium-sized granules; lateral ocular and posterosubmedian carinae distinct; intercarinal surfaces finely and evenly granular (fig. 7D).

Pedipalps: Orthobothriotaxic, Type A; femur dorsal trichobothria with α configuration; pedipalp chela fixed finger, trichobothrium db situated slightly distal to et. Femoral carinae strongly developed, serrate; retromedian carinae comprising spiniform granules; prolateral intercarinal surface with series of large spiniform granules. Patella carinae strongly developed, granular; prolateral intercarinal surface with five or six large, subspiniform granules. Chela manus dorsomedian and retrodorsal carinae complete, granular; prodorsal carina absent. Fixed finger, median denticle row comprising eight oblique subrows, each flanked by pro- and retrolateral supernumerary denticles. Movable finger, median denticle row with short terminal row comprising four denticles preceded by eight oblique subrows, each flanked by pro- and retrolateral supernumerary denticles.

Legs: Leg I length 1.79× greater than carapace length (table 10). Telotarsi ventral surfaces densely covered with short setae; ungues markedly curved.

Pectines: Pectinal plate 1.65× wider than long; posterior margin distinctly rounded; pectinal tooth count 17/17 (♂) (fig. 10C, table 9).

Mesosoma: Tergites width similar to carapace posterior width; I and II slightly narrower (table 9). Pretergites surfaces smooth to finely granular. Posttergites surfaces weakly granular; I–VI with dorsomedian carinae finely granular on I–III, absent on IV–VI; VII surface weakly granular, dorsomedian carina absent, dorsosubmedian and dorsolateral carinae smooth. Sternites III–VI, surfaces smooth; VII surface, ventrolateral and ventrosubmedian carinae smooth.

Metasoma: Metasoma length 3.1× mesosoma length (table 9). Segments longer than wide; increasing in length posteriorly, segment V 2× length of I; carinae finely granular on segments I–III, smooth on IV, absent on V; intercarinal surfaces sparsely granular (figs. 17–22I).

Telson: Vesicle elongate, ovoid; ventral surface shallowly convex; ventromedian carina granular, terminating at subaculear tubercle; subaculear tubercle narrow and angular in lateral aspect, directed toward midpoint of aculeus. Aculeus angled ventrally at slightly less than 90° (fig. 25I).

Variation: Base coloration varies from light yellow to orange with considerable variation in infuscation of the carapace and mesosoma (figs. 40, 41A, B). Adult males and females differ as follows. The prodorsal carina of the pedipalp chela manus is absent, the pectinal tooth count higher (16 or 17), the mesosoma proportionally longer and slenderer, the metasoma up to 3× longer, with segment V markedly longer, and the telson more elongate, with the vesicle more rounded and smoother, in males (figs. 23I, L, 24I, L, 25I, L, table 9). The prodorsal carina is granular and restricted to the distal half of the chela manus, the tegument more densely infuscate, the pectinal plate produced into a rounded lobe posteriorly, which is punctate and slightly infuscate, the pectinal tooth count lower (13 or 14), and the telson shorter and narrower, with the vesicle surfaces weakly granular, in females (figs. 10C, D, 12B, C, 15–16B, 20I, L, 22I, L, 23I, L, 24I, L, 25I, L, table 9).

Distribution: Centruroides chanae is endemic to the states of Guerrero and Michoacán, in southwestern Mexico. The known records extend from eastern Michoacán, near the border of Colima, to western Guerrero, south of the Sierra Madre del Sur and east of the Sierra Madre Occidental (fig. 3).

Ecology: The localities at which C. chanae has been recorded range in altitude from 8 to 221 m. The habitat at these localities varies from low to medium-height deciduous tropical forest and savanna to mangroves and oaks near the coastline. Specimens from Microondas Fogos were collected on fence poles in rangeland at night. The habitat and habitus are consistent with the arboreal, corticolous ecomorphotype (Prendini, 2001a).

Material Examined: MEXICO: Guerrero: Município Copala: Microondas Fogos, 16°33′59.5″N 98°53′18.1″W, 103 m, 22.vi.2007, O.F. Francke, M. Escalante, H. Montaño, and A. Ballesteros, 1 ♂ (AMNH [LP 7032]), 1 juv. ♂ (CNAN SC3983), 14 m, 2.xi.2007, O.F. Francke, H. Montaño, and A. Ballesteros, 3 ♂ (CNAN SC3978), 1 ♀(AMNH [LP 8582]). Michoacán: Município Aquila: Faro de Bucerias, 18°21′08.3″N 103°30′20.9″W, 13 m, 10.iii.2002, J. Ponce, low deciduous forest, 1 juv. ♀ (CNAN SC3982), 13.iv.2002, J. Ponce, low deciduous forest, 2 ♂ (CNAN SC3979, SC3980), 3 ♂(CNAN SC4005), 18°35′50.5″N 103°30′04.3″W, 221 m, 14.iv.2002, J. Ponce and E. González, low deciduous forest, 1 ♂ (AMNH [LP 2009]). Município Aquila: La Llorona, el Faro, 18°20′17.2″N 103°29′49.2″W, 8 m, 6.v.2000, E. Miranda, beach gap, 1 ♂ (CNAN SC3981).

Centruroides schmidti: Francke, 2007: 69, 71, 72, fig. 1 (misidentification); Armas and Martín-Frías, 2008: 7–10, 12, 17, 19, 20, figs. 2–4, table XIV (misidentification).

Type Material: MEXICO: Oaxaca: Município San Juan Bautista Tuxtepec: Holotype ♂ (CNAN T01396), 4 ♀ paratypes (CNAN T01399–T01402), 17 km from San Juan Bautista Tuxtepec, Cerro del Oro Dam, 17°59′55″N 96°15′47.2″W, 74 m, 23.v.1990, E. Barrera and A. Cadena. Veracruz: Município Actopan: 2 ♂ paratypes (CNAN T01397, T01398), Los Idolos, 19°25′44.9″N 96°32′12.4″W, 112 m, 5.v.2006, O.F. Francke, P. Berea, and J. Ballesteros, collected with UV detection.

Etymology: The species name is a noun in apposition, taken from the Nahuatl word meaning “up in a tree” and alludes to the arboreal habitat of species in the genus.

Diagnosis: Centruroides cuauhmapan is most closely related to C. rileyi, from which it differs as follows. The posterosubmedian carinae on the carapace are absent in C. cuauhmapan (fig. 5D) but weakly developed in C. rileyi (fig. 5A). The retrodorsal carina of the pedipalp chela manus is finely granular, the dorsomedian carina distinct, granular, and the prodorsal carina distinct, granular and complete in the male of C. cuauhmapan (figs. 11, 12B), whereas the retrodorsal carina is smooth, the dorsomedian carina weakly granular, and the prodorsal carina weakly granular and restricted to the distal half of the segment in the male of C. rileyi (figs. 11, 12A). The ventrolateral and ventrosubmedian carinae of mesosomal sternite VII are distinct, granular and the intercarinal surfaces finely granular in C. cuauhmapan, whereas the ventrolateral and ventrosubmedian carinae are obsolete to absent and the intercarinal surfaces smooth in C. rileyi. The metasoma and telson are longer in the male and more robust, proportionally longer and broader, in the female of C. cuauhmapan than C. rileyi. The ventrolateral and ventrosubmedian carinae are distinct, granular on metasomal segments I–V in the male and female of C. cuauhmapan (figs. 18G, J, 19G, J, 21G, J, 22G, J), but granular on segment I in the female, vestigial on I–III, and smooth on IV and V in the male of C. rileyi (figs. 18A, D, 19A, D, 21A, D, 22A, D). The surfaces of the telson vesicle of the female are granular in C. cuauhmapan (figs. 23–25J), but smooth in C. rileyi (figs. 23–25D).

Description: The following description is based on the holotype male, with differences among other material noted in the section on variation.

Coloration: Base color pale yellow, with extensive infuscation, creating mottled or marbled pattern. Carapace with uniformly infuscate marbling, more densely infuscate medially. Pedipalp chela fingers and manus, dorsal and retrolateral intercarinal surfaces with moderately infuscate marbling; prolateral and ventral intercarinal surfaces immaculate. Legs retrolateral surfaces with infuscate marbling; prolateral surfaces pale, immaculate. Tergites with unformly infuscate mottling, pale stripe medially, blackish spots submedially, and distinct, narrow bands laterally. Sternites slightly infuscate posteriorly, with faintly infuscate triangular marking at posterior margin of sternite III, fading to infuscate mottling on sternite VII. Metasomal segments uniformly, faintly marbled; segment V and telson markedly infuscate, noticeably darker than preceding segments.

Carapace: Shape trapezoidal; anterior width four-fifths of posterior width (table 3); anteromedian sulcus moderately deep, oval; posteromedian sulcus shallow anteriorly, deeper posteriorly; carinae moderately developed, comprising small to medium-sized granules (fig. 5C).

Pedipalps: Orthobothriotaxic, Type A; femur dorsal trichobothria with α configuration; pedipalp chela fixed finger, trichobothrium db situated slightly distal to et. Femoral carinae granular; dorsal intercarinal surface moderately granular; pro- and retrolateral intercarinal surfaces each with series of large spiniform granules. Patella carinae granular; prolateral intercarinal surface with eight to 10 large subspiniform granules. Chela manus slightly incrassate; dorsal secondary carina well developed, finely serrate; digital and retrolateral secondary carinae moderately developed, finely crenulate; retrodorsal carina well developed, coarsely crenulate; retroventral carina well developed, finely crenulate; proventral carina moderately developed, comprising few rounded granules; prodorsal carina well developed, coarsely serrate. Fixed and movable fingers each shallowly curved proximally. Fixed finger, median denticle row comprising eight oblique subrows, each flanked by pro- and retrolateral supernumerary denticles. Movable finger, median denticle row with short terminal subrow comprising four denticles preceded by eight oblique subrows, each flanked by pro- and retrolateral supernumerary denticles.

Legs: Leg I length 1.92× greater than carapace length (table 10). Telotarsi ventral surfaces densely covered with short setae; ungues strongly curved.

Pectines: Pectinal plate 1.8× wider than long; posterior margin distinctly rounded; pectinal tooth count 14/14 (♂) (fig. 8C, table 3).

Mesosoma: Tergites width similar to carapace posterior width; I and II slightly narrower (table 3). Pretergites surfaces smooth to finely granular. Posttergites surfaces weakly granular; I–VI with dorsomedian carinae vestigial and reduced to several small granules; VII surface finely granular, dorsomedian and dorsosubmedian carinae present, dorsolateral carinae finely serrate. Sternites III–VI, surfaces smooth; VII surface weakly granular, ventrolateral carinae serrate.

Metasoma: Metasoma length 2.86× mesosoma length (table 3). Segments longer than wide; increasing in length posteriorly, segment V 2× length of I; carinae distinct, granular; intercarinal surfaces sparsely granular (figs. 20–22G).

Telson: Vesicle elongate, ovoid; ventral surface shallowly convex, moderately granular; ventromedian carina granular, terminating at subaculear tubercle; subaculear tubercle narrow and angular in lateral aspect, directed toward midpoint of aculeus. Aculeus angled ventrally at slightly less than 90° (figs. 23–25G).

Variation: Adult males and females differ as follows. The dorsomedian carinae of the pedipalp patella are absent, the pectinal tooth count slightly higher (13 or 14), the mesosoma proportionally longer and slenderer, and the metasoma longer, in males (figs. 28A, B, 29A, B, table 3). The first pair of legs are shorter and stouter, the pectinal tooth count slightly lower (11–13), and the metasomal carinae more developed and finely serrate in females (figs. 8C, D, 17G, J, 18G, J, 19G, J, 20G, J, 21G, J, 22G, J, 23G, J, 24G, J, 25G, J, table 3).

Distribution: Centruroides cuauhmapan is endemic to eastern Mexico and recorded from two localities in the state of Veracruz and a third, approximately 200 km south, in the state of Oaxaca (fig. 3).

Ecology: The localities at which C. cuauhmapan has been recorded range in altitude from 74 to 555 m. The habitat at these localities varies from subtropical highland forest to humid subtropical forest. One individual was collected in a coffee plantation in lowland rainforest. The habitat and habitus are consistent with the arboreal, corticolous ecomorphotype (Prendini, 2001a).

Remarks: Specimens from Córdoba, Veracruz, were misidentified as C. schmidti by Armas and Frías (2008). This species has not been recorded from Mexico.

Material Examined: MEXICO: Oaxaca: Município San Juan Bautista Tuxtepec: Cerro del Oro Dam, 17 km from San Juan Bautista Tuxtepec, 17°59′55″N 96°15′47.2″W, 74 m, 23.v.1990, E. Barrera and A. Cadena, 1 ♂ (CNAN SC4001). Veracruz: Município Amatlán de los Reyes: Cañada Blanca, 18°55′43.5″N 96°51′26″W, 555 m, 18.vii.2002, E. González, found in coffee plantation in lowland rainforest, collected at night with UV light, 1 ♂ (AMNH [LP 2073]).

Type Material: MEXICO: Chiapas: Município Ocosingo: Holotype ♂ (CNAN T01408), paratype ♂ (CNAN T01412), paratype ♀ (CNAN T01413), La Galleta, 16°48′18.5″N 90°54′25″W, 103 m, 2.v.2005 A. Valdez, O.F. Francke, and A. Ballesteros, collected with UV light detection; paratype ♂ (CNAN T01414), paratype ♀ (CNAN T01415), same data, except: 2.v.1992, E. Barrera; 2 ♂ paratypes (CNAN T01409, T01411), paratype ♀ (CNAN T01410), same data, except: 114 m, 28.iv.2005, urban area toward blue water bridge.

Etymology: The species name is noun in apposition, taken from the Greek nymph Hamadryas, mother of the hamadryads, tree-dwelling nymphs with lifelong bonds to the trees.

Diagnosis: Centruroides hamadryas is most closely related to C. berstoni, from which it differs in the following respects. The carapace is densely granular, with distinct lateral ocular carinae, in the female of C. hamadryas (fig. 6B) but sparsely granular, more densely so on the interocular triangle, in the female of C. berstoni (fig. 6D). The pedipalp chela manus of the male is proportionally more incrassate in C. hamadryas (fig. 13A) than C. berstoni (fig. 13B). The legs of the male are less than 2× the length of the carapace in C. hamadryas but greater than 2× the length of the carapace in C. berstoni (table 10). The dorsomedian carinae of the mesosomal tergites are distinct and complete in C. hamadryas but weakly developed and restricted to the posterior half of the segments in C. berstoni. The ventrolateral and ventrosubmedian carinae of mesosomal sternite VII are weakly developed to absent in C. hamadryas, whereas the ventrolateral carinae are weakly developed and the ventrosubmedian carinae absent in C. berstoni. The telson vesicle is densely setose in C. hamadryas but sparsely setose in C. berstoni.

Additional differences between C. hamadryas and other species of the clade are as follows. The retrodorsal carina of the chela manus is complete and the dorsomedian carina weakly developed and restricted to the distal half, in the male of C. hamadryas (fig. 13A), whereas the retrodorsal carina is weakly granular and the dorsomedian carina absent in the male of C. berstoni (fig. 13B), C. catemacoensis (fig. 11B), C. cuauhmapan (fig. 11C), and C. rileyi (fig. 11A). The retrodorsal carina of the manus of the female is complete and the prodorsal carina restricted to the distal third in the female of C. hamadryas (fig. 13B), whereas the retrodorsal carina is finely granular and the prodorsal carina absent in the female of C. berstoni (fig. 14B), C. catemacoensis (fig. 12B), C. cuauhmapan (fig. 12C), and C. rileyi (fig. 12A). The pedipalp chela fingers bear short, dense setation in C. hamadryas but sparse setation in C. berstoni. The dorsosubmedian and dorsolateral carinae of metasomal segments I–III are well developed and granular in the male of C. hamadryas (figs. 17–19E) but weakly developed to absent in the male of C. berstoni (figs. 17–19K). The telson vesicle of the male is not posteriorly bilobed in C. hamadryas (figs. 23–25B), unlike C. C. cuauhmapan (figs. 23–25G) and C. rileyi (figs. 23–25A). The vesicle of the female is shorter and more robust, with intercarinal surfaces smooth in C. hamadryas (figs. 23–25E), but sparsely granular in C. berstoni (figs. 23–25K) and densely granular in C. catemacoensis (figs. 23–25P), C. cuauhmapan (figs. 23–25J), and C. rileyi (figs. 23–25D).

Description: The following description is based on the holotype male, with differences among other material noted in the section on variation.

Coloration: Base color pale yellow, with extensive infuscation, creating mottled or marbled pattern. Carapace with uniformly infuscate marbling, more densely infuscate medially. Pedipalp chela fingers and manus, dorsal and retrolateral intercarinal surfaces with moderately infuscate marbling; prolateral and ventral intercarinal surfaces mostly immaculate. Legs retrolateral surfaces with infuscate marbling; prolateral surfaces pale, immaculate. Tergites with unformly infuscate mottling, pale stripe medially, blackish spots submedially, and faint, narrow bands laterally. Sternites pale, with faintly infuscate triangular to trapezoidal marking at posterior margin of sternite III, fading to infuscate mottling on sternite VII. Metasomal segments uniformly, faintly marbled; segment V and telson markedly infuscate, noticeably darker than preceding segments.

Carapace: Shape trapezoidal; anterior width four-fifths of posterior width (table 4); anteromedian sulcus moderately deep, oval; posteromedian sulcus shallow anteriorly, deeper posteriorly; median ocular tubercle moderately granular; carinae weakly developed, comprising small to medium-sized granules (fig. 6A).

Pedipalps: Orthobothriotaxic, Type A; femur dorsal trichobothria with α configuration; pedipalp chela fixed finger, trichobothrium db situated slightly distal to et. Femoral carinae serrate; retromedian carinae comprising spiniform granules; dorsal intercarinal surface moderately granular; prolateral surface with series of large spiniform granules. Patella prodorsal, dorsomedian, retrodorsal and proventral carinae moderately developed, serrate; retromedian carina well developed, serrate; retroventral carina incomplete, serrate; prolateral intercarinal surface with five or six large, subspiniform granules. Chela manus proventral carina moderately developed, comprising few rounded granules; other carinae weakly developed, granular. Fixed finger, median denticle row comprising eight oblique subrows, each flanked by pro- and retrolateral supernumerary denticles. Movable finger, median denticle row with short terminal row comprising four denticles preceded by eight oblique subrows, each flanked by pro- and retrolateral supernumerary denticles.

Legs: Leg I length 1.88× greater than carapace length (table 10). Telotarsi ventral surfaces densely covered with short setae; ungues markedly curved.

Pectines: Pectinal plate 1.9× wider than long; posterior margin distinctly rounded; pectinal tooth count 14/14 (♂) (fig. 6A, table 4).

Mesosoma: Tergites width similar to carapace posterior width; I and II slightly narrower (table 4). Pretergites surfaces smooth to finely granular. Posttergites surfaces weakly granular; I–VI with dorsomedian carinae moderately granular; VII surface weakly granular, dorsomedian carina moderately granular, dorsosubmedian carinae serrate, dorsolateral carinae well developed. Sternites III–VI, surfaces smooth; VII surface weakly granular, ventrolateral carinae reduced to few granules.

Metasoma: Metasoma length 3.01× mesosoma length (table 4). Segments longer than wide; increasing in length posteriorly, segment V 2× length of I; carinae complete, granular on segments I–III, other carinae absent or obsolete; intercarinal surfaces sparsely granular (figs. 17–22E).

Telson: Vesicle elongate, ovoid; ventral surface shallowly convex, sparsely granular posteriorly; ventromedian carina granular, terminating at subaculear tubercle; subaculear tubercle narrow and angular in lateral aspect, directed toward midpoint of aculeus. Aculeus angled ventrally at slightly less than 90° (fig. 25B, E).

Variation: Adult males and females differ as follows. The pectinal tooth count is slightly higher (14 or 15), the mesosoma proportionally longer and slenderer, and the metasoma up to 3× longer, with segment V also roughly 1.5 mm longer, in males (figs. 23B, E, 24B, E, 25B, E, table 4). The tegument is more densely infuscate, the pectinal plate produced into a rounded lobe posteriorly, which is punctate and slightly infuscate, the pectinal tooth count slightly lower (12 or 13), and the telson shorter and narrower, in females (figs. 9A, B, 23B, E, 24B, E, 25B, E, 32A, B, 33A, B, table 4).

Distribution: Centruroides hamadryas is known only from the state of Chiapas in southeastern Mexico, but may extend across the Usu-macinta River into Guatemala. The known records occur in the Lacondón Forest, on the northern edge of the Montes Azules Biosphere Reserve (fig. 4).

Ecology: The localities at which C. hamadryas has been recorded range in altitude from 103 to 153 m, all situated in a lowland tropical rainforest. Most specimens of this strictly arboreal species were located with UV light detection at night and captured by holding an insect net beneath the branch on which they were sitting and tapping the branch with a stick; their escape reaction is to drop immediately to the leaf litter below, where they invariably disappear. The habitat and habitus are consistent with the arboreal, corticolous ecomorphotype (Prendini, 2001a).

Remarks: Specimens from Frontera Corozal, Chiapas, Mexico, were misidentified as C. schmidti by Francke (2007). Teruel and Stockwell (2002) and Francke (2007) noted differences among the pectinal counts of specimens from Chiapas, with 13–16 (♂) and 13–14 (♀), and Honduras, with 12–15 (♂) and 13–15 (♀). Although this slight variation in pectinal tooth counts does not provide sufficient evidence to distinguish between C. hamadryas and C. schmidti, additional morphological differences, outlined in their respective diagnoses, together with genetic divergence among samples from the two areas, confirmed the distinction between them.

Material Examined: MEXICO: Chiapas: Município Ocosingo: La Galleta, 2 km SE of Frontera Corozal, 16°48′12.7″N 90°52′11.1″W, 132–150 m, 28.iv.2004, R. Paredes and J.L. Castelo, collected with UV light detection, 2 ♂ (AMNH [LP 2948]), 1 ♀ (CNAN SC3987), 16°49′55″N 90°56′08″W, 146 m, 7.iv.2005, A. Valdez, O.F. Francke, and A. Ballesteros, collected at night with UV lamp, 1 juv. ♂ (CNAN SC3986), 16°48′18.5″N 90°54′25″W, 114 m, 28.iv.2005, A. Valdez, O.F. Francke, and A. Ballesteros, urban area toward blue water bridge, collected with UV light detection, 2 ♂, 1 ♀, 1 juv. ♂, 1 juv. (CNAN SC3988).

Centruroides hoffmanni Armas, 1996: 29–32, figs. 5–9; 1999: 47, 51; Beutelspacher-Baigts, 2000: 123, 126, 139, 144, 155, map 106 (in part: records from Arriaga, Chiapas); Kovařík, 1998: 107; Fet and Lowe, 2000: 109; González-Santillán, 2001: 573; Armas et al., 2002: 94, 95; 2003: 94 (misidentification); 2004: 170, table 1 (misidentification); Martín-Frías et al., 2005: 1–6, figs. 1–13 (misidentification); Teruel et al., 2006: 223; Santibáñez-López and Ponce-Saavedra, 2009: 321, 323, 326, 328–231, figs. 12–15, 8–11, 16 (misidentification); Santibáñez-López and Contreras-Felix, 2013: 131, 138, fig. 7 (misidentification); Teruel et al., 2015a: 3, 6, 7, figs. 35–37 (misidentification); Kovařík et al., 2016b: 11 (misidentification); Esposito et al., 2017: 13; Esposito and Prendini, 2019: 4, 7, fig. 2.

Type Material: MEXICO: Chiapas: Município Arriaga: Holotype ♀, (CNAN 71), La Gloria 16°08′39.4″N 94°06′04.7″W, 11.xii.1974. J.L. Garcia, R. Ruiz, and J. Luis M.G., household collection.

Diagnosis: Centruroides hoffmanni is most closely related to C. chanae, from which it differs as follows. A dark line along the lateral margins of the carapace and mesosomal tergites I–III, and pale stripe medially on the carapace and tergites, absent in C. hoffmanni (fig. 7A, B) are present in C. chanae (fig. 7C, D). The carapace, pedipalps, tergites, and metasoma are more infuscate, creating a more mottled appearance, in C. hoffmanni (figs. 38A, B, 39A, B) than C. chanae (figs. 40A, B, 41A, B). Less reticulate infuscation is present on the chelicerae of C. hoffmanni than C. chanae. The interocular triangle is more darkly infuscate in C. hoffmanni than C. chanae. The marbled infuscation of the mesosomal sternites is pronounced in C. hoffmanni, but faint or absent in C. chanae. The carapace is longer, its length greater than its width, in C. hoffmanni, but shorter, its length and width similar, in C. chanae (tables 8, 9). The carapace surfaces are more coarsely granular, the carinae more pronounced, and the sulci narrower and deeper in C. hoffmanni (fig. 7A, B) than C. chanae (fig. 7C, D). The pedipalp chela manus of the male is more incrassate in C. hoffmanni than C. chanae (fig. 15A, B). The ventral surfaces of the telotarsi of leg I are more finely and sparsely setose in C. hoffmanni than C. chanae. The pectinal tooth count of the male is lower in C. hoffmanni, usually 15, than C. chanae, usually 17 (table 8). The ventrolateral carinae of mesosomal sternite VII are granular, and the ventrosubmedian carinae weakly granular and restricted to the posterior half of the segment in C. hoffmanni, whereas the ventrolateral carinae are distinct, granular, and the ventrosubmedian carinae weakly developed, granular in C. chanae. Although the metasomal segments of the male are longer and narrower in C. hoffmanni than C. chanae, the metasoma is less than 3× the length of the mesosoma in C. hoffmanni but greater than 3× (up to 3.3×) its length in C. chanae (table 10). The ventrolateral and ventrosubmedian carinae of the metasomal segments are more pronounced in C. hoffmanni, being slightly serrate on segments I–IV, compared with finely granular to subserrate on I–III and obsolete, smooth on IV in C. chanae. The ventrosubmedian carinae of segments I and II are very pronounced in C. hoffmanni (figs. 18C, F, 19C, F) but absent or obsolete in C. chanae (figs. 18I, L, 19I, L). The telson of the male is elongate, the vesicle bilobed posteriorly in C. hoffmanni (fig. 25C, F), whereas the telson is shorter, the vesicle rounded posteriorly in C. chanae (fig. 25I, L).

Distribution: Centruroides hoffmanni is endemic to the state of Chiapas in southeastern Mexico. The known records are restricted to the Central Depression, bounded by the Central Highlands, to the north, and the Sierra Madre de Chiapas, to the south (fig. 4), an area which exhibits high levels of endemism (Reyes-García and Sousa, 1995).

Ecology: The localities at which C. hoffmanni has been recorded range in altitude from 529 to 1513 m and are situated in subtropical dry forest. The habitat and habitus are consistent with the arboreal, corticolous ecomorphotype (Prendini, 2001a).

Remarks: Confusion has surrounded this species since its original description. Armas (1996) described the holotype as an adult female, but later (Armas, 1999; Armas et al. 2003) stated it was immature. Beutelspacher-Baigts (2000) confused C. hoffmanni with Centruroides nigrovariatus Pocock, 1898, and C. tuxtla, erroneously listing the species from the Mexican state of Oaxaca, an error repeated by Armas et al. (2003, 2004). Martín-Frías et al. (2005) redescribed C. hoffmanni from material originating in Oaxaca that is evidently hetero-specific with the holotype based on characters of the female: the pectinal plate of the material described is not distinctly lobed or posteriorly rounded, the pectinal tooth count is higher, the metasoma and telson markedly are granular, and the subaculear tubercule is not elongate and angular. Santibáñez-López and Ponce-Saavedra (2009) again misidentified C. hoffmanni, presenting photographs of female specimens in which the pectinal plate is not distinctly lobed or posteriorly rounded, along with measurements and pectinal tooth counts inconsistent with the holotype, once more erroneously listing the species from Oaxaca. The error was repeated by Santibáñez-López and Contreras-Félix (2013), and yet again by Teruel et al. (2015a), who erroneously associated C. hoffmanni with the “nigrovariatus group” of Centruroides. Kovařík et al. (2016b) followed previous authors in misidentifying material from Guerrero and Oaxaca as C. hoffmanni.

Material Examined: MEXICO: Chiapas: Município Angel Albino Corzo: 8 km from Siltepec, 18°48′33″N 92°40′30.6″W, 663 m, 17.viii.2007, C. Mayorga, G. Ortega, and L. Cervantes, 1 juv. ♀ (CNAN SC3990). Município Comitan: Parque Nacional Lagunas de Montebelo, 16°17′17″N 91°56′16″W, 1473 m, 3.ix.2005, O.F. Francke, M. Córdova, A. Jaimes, A. Valdez, and H. Montaño, 1 juv. ♂ (CNAN SC3992). Município La Concordia: Villa Corzo La Tigrilla, San Julián, Revolución Mexicana, 16°00′00″N 92°50′47″W, 544 m, 17.iii.2007, C. Mayorga, G. Ortega, and L. Cervantes. 1 ♂, 1 ♀ (CNAN SC3998). Município Tuxtla Gutiérrez: Las Delicias, 16°45′31.1″N 93°06′26.4″W, 529 m, 2.iii.2005, O.F. Francke, M. Córdova, A. Jaimes, A. Valdez, and H. Montaño, 1 ♀ (AMNH [LP 5224]); Gutiérrez, San Julián, Revolución Mexicana, 16°11′41″N 93°01′16″W, 544 m, 16.iii.2007, G. Ortega and A. Cervantes, 2 ♂, 3 ♀ (CNAN SC3997). Município Tzimol: Carretera [Hwy] Comitán–Tzimol Santa Rosa, 16°11′03.4″N 92°16′59.3″W, 632–730 m, 2.ix.2005, O.F. Francke, M. Córdova, A. Jaimes, A. Valdez, and H. Montaño, 1 ♂, 1 ♀ (AMNH [LP 5249]), 1 ♀, first instar juvs (CNAN SC3994), 1 ♀, first instar juvs (CNAN SC3995), 3 ♂, 9 ♀, 2 juv. ♂, 14 juv. ♀ (CNAN SC3996). Município Villaflores: Reserva de La Biosfera La Sepultura, 1 km SE of Ejido California, 16°15′14.2″N 93°35′46.4″W, 1009–1132 m, 30.viii.2005, O.F. Francke, M. Córdova, A. Jaimes, A. Valdez, and H. Montaño, 1 ♂ (AMNH [LP 5350]), 1 ♂, 2 ♀, 4 juv. ♂ (CNAN SC3993), 1 ♀, first instar juvs (CNAN SC3991).

Centruroides rileyi Sissom, 1995: 96–99, figs. 19–27; Armas et al., 2002: 1; 2003: 95; Cancino and Blanco, 2002: 71; Sissom and Hendrixson, 2005: 126, 127, 134, 475; Esposito et al., 2017: 14, 30, fig: 14; 2018: 97, 116; Esposito and Prendini, 2019: 4, fig. 2; Ponce-Saavedra and Francke, 2019: 3; Crews and Esposito, 2020: 14, fig. 11; Goodman and Esposito, 2020: 1–9, fig. 1C (misidentification).

Type Material: MEXICO: Tamaulipas: Município Gómez Farías: Holotype ♂, paratype ♀ (USNM), Bocatoma, 7 km SSE of Gómez Farías, 22°56′30.2″N 99°06′19.3″W, 25–30. iii.1978, E.G. Riley; paratype ♀ (FSCA), Gómez Farías, 16.iii.1977, R. Schmidt. San Luis Potosí: Município Tamazunchale: Paratype ♀ (NAU), 5 km N of Tamazunchale off Hwy 85, 21°18′13.6″N 98°47′58.7″W, 1.viii.1987, J.A. Nilsson.

Diagnosis: Centruroides rileyi is most closely related to C. cuauhmapan, from which it differs as follows. The posterosubmedian carinae of the carapace are weakly developed in C. rileyi (fig. 5A, B), but absent in C. cuauhmapan (fig. 5C, D). The retrodorsal carina of the pedipalp chela manus is smooth, the dorsomedian carina weakly granular, and the prodorsal carina weakly granular and restricted to the distal half of the segment, in the male of C. rileyi (figs. 11, 12A) whereas the retrodorsal carina is finely granular, the dorsomedian carina distinct, granular, and the prodorsal carina distinct, granular and complete in the male of C. cuauhmapan (figs. 11, 12B). The ventrolateral and ventrosubmedian carinae of mesosomal sternite VII are obsolete to absent and the intercarinal surfaces smooth in C. rileyi, whereas the ventrolateral and ventrosubmedian carinae are distinct, granular and the intercarinal surfaces finely granular in C. cuauhmapan. The metasoma and telson are shorter in the male and slenderer, proportionally shorter and narrower, in the female of C. rileyi (figs. 17A, D, 18A, D, 19A, D, 20A, D, 21A, D, 22A, D, 23A, D, 24A, D, 25A, D, table 2) than C. cuauhmapan (figs. 17G, J, 18G, J, 19G, J, 20G, J, 21G, J, 22G, J, 23G, J, 24G, J, 25G, J, table 3). The ventral carinae are granular on metasomal segment I in the female, vestigial on segments I–III and smooth on IV and V in the male of C. rileyi (figs. 18A, D, 19A, D, 20A, D, 21A, D, 22A, D) but distinct, granular on segments I–V in the male and female of C. cuauhmapan (figs. 18G, J, 19G, J, 20G, J, 21G, J, 22G, J). The surfaces of the telson vesicle of the female are smooth in C. rileyi (figs. 24A, D, 25A, D) but granular in C. cuauhmapan (figs. 24G, J, 25G, J).

Variation: Adult males and females differ as follows. The dorsomedian carinae of the pedipalp patella are absent, the mesosoma proportionally longer and slenderer, and the metasoma longer, in males (figs. 26A, B, 27A, B, 28A, B, 29A, B, table 2). The first pair of legs are longer in males and the metasomal carinae more pronounced and finely serrate in females (figs. 17A, D, 18A, D, 19A, D, 20A, D, 21A, D, 22A, D, table 2).

Distribution: Centruroides rileyi is endemic to northern Mexico, east of the Sierra Madre Oriental. The species is fairly widespread, with records from the states of Puebla, Tamaulipas, San Luis Potosí, and Veracruz (fig. 3).

Ecology: The localities at which C. rileyi has been recorded range in altitude from 100 to 2554 m. The habitat at these localities varies from subtropical and semi-deciduous forests near the El Cielo Biosphere Reserve, Tamaulipas, to tropical and subtropical moist broadleaf forest at La Sierra Gorda, San Luis Potosí, and tropical humid moist forest in Veracruz (Mendoza-Villa et al., 2018). The habitat and habitus are consistent with the arboreal, corticolous ecomorphotype (Prendini, 2001a).

Remarks: Centruroides rileyi has never been confused with other species of the “thorellii” clade nor with C. thorellii, perhaps due to its occurrence in northern Mexico. Furthermore, the small size and distinctive mottling pattern contrast with other buthids, such as Centruroides gracilis (Latreille, 1804) and Centruroides vittatus (Say, 1821), that occur in sympatry (Shelley and Sissom, 1995).

Material Examined: MEXICO: Puebla: Município Cuetzalan el Progreso: Cuetzalan, Santiago Yancuitlalpan, 18°54′42.2″N 98°35′15.3″W, 2554 m, 19.v.1995, G. Oclogaig Barrzia, juvs (CNAN SC3999). San Luis Potosí: Município Axtlan de Terrazas: Axtlan de Terrazas, 21°25′34.9″N 98°52′42″W, 100 m, 28.iv.2006, O.F. Francke, A. Valdez, G. Villegas and R. Paredes, 1 ♂ (AMNH [LP 6445]), 1 ♀, 2 juv. ♀(CNAN SC4003). Veracruz: Município Papantla: Papantla, 20°27′24.1″N 97°18′56.1″W, 2197 m, iii.2000, J.L. Castelo, 1 ♂ (CNAN SC4000). Município Tamiahua: Moralillo, Cerro Azul, 21°11′03.8″N 97°44′49.6″W, 153 m, 27.ii.2007, E. Barrera and L. Cervantes, 2 ♀ (CNAN SC3985), 1 juv. ♀ (CNAN SC4002).

Centruroides schmidti Sissom, 1995: 94–96, 98, figs. 10–18; Armas, 1996: 22–24, table I (misidentification, part); 1999: 30; Vázquez, 1999: 53, 60–62, fig. 7 (misidentification, part); Armas and Maes, 2000: 27; 2001: 16; Fet and Lowe, 2000: 118; Armas et al., 2002: 169–171 (misidentification); Teruel and Stockwell, 2002: 111–127, figs. 6, 20, tables II, III; Armas et al., 2003: 95–96 (misidentification); Armas and Martín-Frías, 2003: 205, 209; 2008: 7–10, 12, 17, 19, 20, figs. 2–4, table XIV (misidentification); Armas and Trujillo, 2010: 235, 238, 240; Borges et al., 2012: 131, table I; Teruel et al., 2015a: 7; Delfín-González et al., 2017: 284 (misidentification), table I; Esposito et al., 2018: 97, table 5; Esposito and Prendini, 2019: 4, fig. 2; Crews and Esposito, 2020: 14, fig. 11.

Type Material: HONDURAS: Departamento Cortés: Município Choloma: Holotype ♂(FMNH), Coloma [Choloma], Lake Ticamaya 15°32′41.5″N 87°53′06.1″W, 26.iv.1923, K. Schmidt and L. Walters (Capt. Field Mus. Exped.), found on bones of crocodile skull. GUATEMALA: Departamento Izabal: Município Morales: Paratype ♀ (FMNH), Escobas, Izabal 15°24′12″N 89°08′24.5″W 27.xi.1933, K.P. and P.J. Schmidt, Leon Mandel Guatemala Exped.

Diagnosis: Centruroides schmidti differs from the closely related species, C. berstoni, C. catemacoensis, C. cuauhmapan, C. hamadryas, and C. rileyi, as follows. The pattern of infuscation of C. schmidti is unlike that of the other species and includes a pronounced pale stripe medially on the carapace and mesosomal tergites, flanked on the tergites by a pair of orange stripes, which are more infuscate in females (figs. 36A, B, 37A, B). The cheliceral manus is entirely dark with reticulate infuscation in C. schmidti, whereas the infuscation is lighter and restricted to the distal half of the chelicerae in the other species. The telotarsi of the first pair of legs possess short, dense setae in C. schmidti, unlike in C. cuauhmapan and C. rileyi. The posterosubmedian and lateral ocular carinae on the carapace are present in C. schmidti (fig. 6E, F) but reduced or absent in C. catemacoensis (fig. 5E, F) and absent in C. berstoni (fig. 6C, D), C. cuauhmapan (fig. 5C, D), and C. hamadryas (fig. 6A, B). The posterior margin of sternite III is pale and setose in C. schmidti, unlike in the other species. The dorsomedian carinae are restricted to the posterior two-thirds of tergites I–VI, and absent on VII in C. schmidti, whereas the dorsomedian carinae are vestigial on tergites I–VII in C. catemacoensis and weakly granular on I–VII in C. berstoni. Ventrosubmedian and ventrolateral carinae are present on sternite VII in C. schmidti, unlike in C. catemacoensis and C. rileyi. Metasomal segment V is more than 2× the length of the carapace in C. schmidti, but less than 2× its length in the other species (table 7). The telson surfaces of the female are very granular and the ventromedian carina well developed in C. schmidti (figs. 23–25D), whereas the telson surfaces of females are smooth in C. hamadryas (figs. 23–25E) and C. rileyi (figs. 23–25Q). The subaculear tubercle is strongly angled toward the aculeus in C. schmidti (fig. 25N, Q)

Centruroides schmidti differs from C. hoffmanni as follows. The mottled infuscation of the carapace, pedipalps, tergites, and metasoma is less pronounced in C. schmidti than C. hoffmanni, but the carapace is more infuscate, with a darker border around the margins, in C. schmidti. The carapacial sulci are broad and shallow in C. schmidti but narrow and deep in C. hoffmanni. The dorsomedian carina is restricted to the posterior two-thirds of tergites I–VI, and absent on VII in C. schmidti, whereas the dorsomedian carina is complete on tergites I–VII in C. hoffmanni.

Variation: Carapace surface granulation varies from sparse granules to uniform, moderate granulation. Specimens from Honduras exhibit variation in granulation of the lateral ocular carinae (fig. 6E, F). The dorsomedian carina of the pedipalp chela manus of the male is well developed in material from Guatemala but weakly developed to absent in material from Honduras.

Adult males and females differ as follows. The pedipalp chela of the male is incrassate unlike the female. The prodorsal carina on the chela manus comprises a row of spiniform granules in the male but is finely granular in the female (fig. 13C, D). The mesosoma is proportionally longer and slenderer, the metasoma up to 3× longer, with segment V markedly longer, and the telson more elongate, with the vesicle more rounded, in males (figs. 17N, Q, 18N, Q, 19N, Q, 20N, Q, 21N, Q, 22N, Q, 23N, Q, 24N, Q, 25N, Q, table 2).

Distribution: Centruroides schmidti is the most widespread species of the clade. It appears to be endemic to Guatemala, where it has been recorded from the Izabal and Zacapa departments, and Honduras, where it has been recorded from the Atlántida, Cortés, Francisco Morazán, and Islas de la Bahía departments. The known localities extend along the Caribbean coasts of both countries, including the Bay Islands of Honduras, and inland to the Sierra de Las Minas of Guatemala (fig. 4).

Ecology: The localities at which C. schmidti has been recorded range in altitude from 12 to 773 m. This species occurs in a broader range of habitats than other species of the “thorellii” clade. The habitat at localities near Zacapa, Guatemala is semiarid savannah, dominated by scrub forest and cacti. In this area, specimens were found on the bark of large oaks at night. The habitat at San Antonio de Oriente, Honduras, is open deciduous broadleaf forest/savannah, interspersed with grassland. The habitat near Las Minas, Guatemala, is moist montane subtropical pine-oak forest; specimens were collected on Pinus oocarpa Schiede ex Schltdl. and various oak species (fig. 2A, C). The habitat on the northern coast and Bay Islands of Honduras is lowland tropical rainforest. The habitat and habitus are consistent with the arboreal, corticolous ecomorphotype (Prendini, 2001a).

Remarks: Previous records of C. schmidti from Costa Rica and the Mexican states of Chiapas, Quintana Roo, and Veracruz are misidentifications of other species, including some of those described herein. Armas (1996) included specimens from Quintana Roo, probably conspecific with C. yucatanensis, in a redescription of C. schmidti. Armas et al. (2002) described an individual from northern Costa Rica as C. schmidti, without differentiating it from C. thorellii, a species erroneously recorded from the country by Francke and Stockwell (1987). Armas et al. (2003) included Mexico (Chiapas, Quintana Roo, and Yucatán) in the distribution of C. schmidti. Vázquez (1999) again included C. schmidti in the fauna of Quintana Roo and erroneously suggested the species is endemic to the Yucátan Peninsula. Photographs and measurements of individuals identified as C. schmidti from the Sian Ka'an Biosphere Reserve, Quintana Roo, by Armas and Martín-Frías (2008), are consistent with the coloration and morphology of C. yucatanensis. Additionally, Armas and Martín-Frías (2008) listed C. schmidti from Veracruz. Delfín-González et al. (2017) listed C. schmidti from Chiapas and Veracruz. Finally, Armas and Martín-Frías (2003) erroneously suggested that the distribution of C. schmidti extends from southeastern Mexico to Costa Rica, following Armas et al. (2002).

Material Examined: GUATEMALA: Departamento El Progreso: Município Rio Hondo: San Francisco Zapotitlan: Finca El Olvido, Las Minas, 15°02′04.8″N 89°52′26.7″W, 1214 m, 17.ix.2019, A.M. Goodman, UV hand collection, found on oak and pine trees, 2–3 m high, 4 ♀, 4 juv. ♀ (CASENT 9073317), 18.ix.2019, A.M. Goodman, L.A. Esposito, and L. Allen, 5 ♀, 1 juv. ♂, 1 juv. ♀ (CASENT 9073402). Departamento Zacapa: Município Rio Hondo: Bosque Pino, Guadalupe, Manta de Golpeo, 14°58′04.7″N 89°24′47″W, 751 m, 20.ix.2019, A.M. Goodman, M. Barrios, and M. van Dam, UV hand collection, found on oak and pine trees, 2–3 m high, 7 ♂, 1 ♀, 1 juv. ♂, 1 juv. ♀ (CASENT 9073278); Aldea Casas de Pinto, near turnoff for Zacapa at Rio Hondo, 15°01′38.2″N 89°36′57.2″W, 77 m, 13.vii.2006, J.H. Huff, semiarid region with scrub forest and cacti, collected under rocks in shaded areas and at night using UV, 1 ad. (AMNH [LP 5985]). HONDURAS: Departamento Atlántida: Município La Ceiba: Parque Nacional Pico Bonito, Pico Bonito, trails from Visitor Centre and park entrance, 14°43′30.6″N 86°44′11.5″W, 184 m, 30.viii.2013, S. Longhorn, dense wet lowland tropical forest near large river, sweeping and beating, may have been on or under wood, day search, 1 juv. ♂ (AMNH [LP 13416]). Departmento Francisco Morazán: Município San Antonio de Oriente: E.A.P. Zamorano, Monte Redondo, Acuacultura, 13°39′59.6″N 86°59′21″W, 773 m, 23.ix.2008, C. Víquez, UV at night, 1 ♀ (AMNH [LP 9172]). Departamento Islas de la Bahía: Município Roatán: Cayos Cochinos, Cayos Menor, forest trails, 15°57′26.9″N 86°30′03.3″W, 101 m, 2.viii.2012, S. Longhorn, scrub oak forest, 1 ♀ (AMNH [LP 13411]); Isla Utila, 16°06′22.1″N 86°54′08.1″W, 12 m, 21.vii.2012. S. Longhorn, scrub forest/wet Savannah, 1 ♀ (AMNH LP [13417]).

Centruroides schmidti: Armas, 1996: 25–29, 98, figs. 1–4 (misidentification), table I.

Centruroides sissomi: Vázquez, 1999: 53, 60–62, fig. 7 (misidentification); Armas et al., 2003: 95 (misidentification, part); Armas, 2006: 4, 7, fig. 5 (misidentification, part); Teruel et al., 2015a: 8 (misidentification); Delfín-González et al., 2017: 283, 285, table 2 (misidentification); Esposito and Prendini, 2019: 4, fig. 2 (misidentification); Ponce-Saavedra and Francke, 2019: 3, table 1 (misidentification); Crews and Esposito, 2020: 14, fig. 11 (misidentification).

Type Material: MEXICO: Quintana Roo: Município Benito Juárez: Holotype ♂ (CNAN T01416), paratype ♀ (CNAN T01417), 2 juv. ♀paratypes (CNAN T01418, T01419), Puerto Morelos, Jardín Botánico Alfredo Barrera, 20°50′42.1″N 86°54′12.9″W, 23 m, 4.vii.2007, G. Montiel, R. Paredes, M. Ramírez, D. Chibras, and G. Bonilla.

Etymology: The species name refers to the Yucatán Peninsula of southeastern Mexico, where the species occurs.

Diagnosis: Centruroides yucatanensis differs from the closely related species, C. chanae and C. hoffmanni, as follows. The carapace, pedipalps, tergites, and metasoma are less infuscate, creating a less mottled appearance, in C. yucatanensis than C. chanae. Less reticulate infuscation is present on the chelicerae of C. yucatanensis than C. chanae. The interocular triangle is less darkly infuscate in C. yucatanensis than C. hoffmanni. The carapace is shorter, its length and width similar, in C. yucatanensis (fig. 7E, F, table 10) but longer, its length greater than its width, in C. hoffmanni (fig. 7A, B, table 10). The carapace surfaces are more finely granular, the carinae less developed and the sulci broader and shallower in C. yucatanensis than C. hoffmanni. The pedipalp chela manus of the male is less incrassate in C. yucatanensis (fig. 15C) than C. hoffmanni (fig. 15B), with fewer spiniform granules on its prolateral surfaces than in C. chanae and C. hoffmanni (fig. 15A, B). The ventral surfaces of the telotarsi of leg I are more finely and sparsely setose in C. yucatanensis than C. chanae. The pectinal tooth count of the male is lower in C. yucatanensis, usually 13 or 14 (fig. 9E, table 10) than C. chanae, usually 17 (fig. 9A, table 10) and C. hoffmanni, usually 15 (fig. 9D, table 10), and the pectinal teeth are more ovoid. The ventrolateral and ventrosubmedian carinae of mesosomal sternite VII are vestigial, weakly granular in C. yucatanensis, whereas the ventrolateral carinae are distinct, granular, and the ventrosubmedian carinae weakly developed, granular in C. chanae, and the ventrolateral carinae granular, and the ventrosubmedian carinae weakly granular and restricted to the posterior half of the segment in C. hoffmanni. The ventrolateral and ventrosubmedian carinae of the metasomal segments are more pronounced in C. yucatanensis, being slightly serrate on segments I–IV, compared with finely granular to subserrate on I–III and obsolete, smooth on IV in C. chanae. The ventrosubmedian carinae of segments I and II are absent in C. yucatanensis (figs. 18O, R, 19O, R, 20O, R, 21O, R, 22O, R), absent or obsolete in C. chanae (figs. 18I, L, 19I, L, 20I, L, 21I, L, 22I, L), and very pronounced in C. hoffmanni (figs. 18C, F, 19C, F, 20C, F, 21C, F, 22C, F).

Description: The following description is based on the holotype male, with differences among other material noted in the section on variation.

Coloration: Base color yellow, with extensive infuscation, creating mottled or marbled pattern. Carapace with uniformly infuscate marbling, more densely infuscate medially. Pedipalp chela fingers and manus, dorsal and retrolateral intercarinal surfaces with moderately infuscate marbling; prolateral and ventral intercarinal surfaces mostly immaculate. Legs retrolateral surfaces with infuscate marbling; prolateral surfaces pale, immaculate. Tergites with unformly infuscate mottling, pale stripe medially, blackish spots submedially, and faint, narrow bands laterally. Sternites with faintly infuscate marbling. Metasomal segments uniformly, faintly marbled; segment V and telson markedly infuscate, noticeably darker than preceding segments.

Carapace: Shape trapezoidal; anterior width four-fifths of posterior width (table 10); anteromedian sulcus moderately deep, oval; posteromedian sulcus shallow anteriorly, deep posteriorly; median ocular tubercle weakly granular; carinae moderately developed, comprising small to medium-sized granules; lateral ocular and posterosubmedian carinae weakly developed; intercarinal surfaces finely and evenly granular (fig. 10E).

Pedipalps: Orthobothriotaxic, Type A; femur dorsal trichobothria with α configuration; pedipalp chela fixed finger, trichobothrium db situated slightly distal to et. Femoral carinae strongly developed, serrate; dorsal intercarinal surface moderately granular; prolateral intercarinal surface with series of large spiniform granules. Patella carinae strongly developed, granular; prolateral intercarinal surface with five or six large subspiniform granules. Chela manus dorsomedian and retrodorsal carinae complete, granular; prodorsal carina absent. Fixed finger, median denticle row comprising eight oblique subrows, each flanked by pro- and retrolateral supernumerary denticles. Movable finger, median denticle row with short terminal row comprising four denticles preceded by eight oblique subrows, each flanked by pro- and retrolateral supernumerary denticles.

Legs: Leg I length 1.78× greater than carapace length (table 10). Telotarsi ventral surfaces sparsely covered with short setae; ungues markedly curved.

Pectines: Pectinal plate 1.61× wider than long; posterior margin distinctly rounded; pectinal tooth count 13/14 (♂) (fig. 8D, table 10).

Mesosoma: Tergites width similar to carapace posterior width; I and II slightly narrower (table 10). Pretergites surfaces smooth to finely granular. Posttergites surfaces weakly granular; I–VI with dorsomedian carinae absent on I and II, vestigial, granular on III–VI; VII surface weakly granular, dorsomedian carina vestigial, granular, dorsosubmedian and dorsolateral carinae smooth. Sternites III–VI, surfaces smooth; VII surface smooth, ventrolateral and ventrosubmedian carinae smooth.

Metasoma: Metasoma length 2.45× mesosoma length (table 10). Segments longer than wide; increasing in length posteriorly, segment V 2× length of I; ventral carinae vestigial, weakly granular on segments I–IV, other carinae absent or obsolete; lateral intercarinal surfaces sparsely granular on segments I–III, other surfaces smooth (figs. 17–22O).

Telson: Vesicle elongate, ovoid; ventral surface shallowly convex; ventromedian carina granular, terminating at subaculear tubercle; subaculear tubercle narrow and angular in lateral aspect, directed toward midpoint of aculeus. Aculeus angled ventrally at slightly less than 90° (fig. 25O, R).

Variation: Base coloration varies from light yellow to orange. Adult males and females differ as follows. The pedipalp chela manus is incrassate, with the prodorsal carina spinose, the mesosoma proportionally longer and slenderer, the metasoma 2× longer, with segment V markedly longer (1.86× carapace length), and the telson more elongate, with the vesicle more rounded and bilobed posteriorly, in males (figs. 23O, R, 24O, R, 25O, R, table 10). The tegument is more densely infuscate, the prodorsal carina of the pedipalp chela manus finely granular, the pectinal plate produced into a rounded lobe posteriorly, which is punctate and slightly infuscate, metasomal segment V shorter (1.3× carapace length) and the telson shorter and narrower, with the vesicle surfaces less granular, in females (figs. 10E, F, 15–16C, 17O, R, 18O, R, 19O, R, 20O, R, 21O, R, 22O, R, 23O, R, 24O, R, 25O, R, table 10). The pectinal tooth count is similar in both sexes (table 9).

Distribution: Centruroides yucatanensis is endemic to the Yucatán Peninsula. Although presently known from only three localities, two in the state of Yucatán in the north of the peninsula, and a third on the western coast, in the state of Quintana Roo, the distribution of this species was probably more extensive before much of its habitat was destroyed for agriculture and rangeland (fig. 4).

Ecology: The localities at which C. yucatanensis has been recorded range in altitude from 23–38 m. The habitat at these localities varies from low or medium semideciduous broadleaf forest to tall, moist evergreen broadleaf forest, often with a dense understory. Much of the original habitat has been cleared for agriculture and rangeland across the Yucatán Península, and this species appears to be confined to remnant patches of forest. The habitat and habitus are consistent with the arboreal, corticolous ecomorphotype (Prendini, 2001a).

Remarks: Armas (1996) identified 11 individuals from the Jardín Botánico Alfredo Barrera, Puerto Morelos, Quintana Roo, as C. schmidti. Meristic data recorded by Armas (1996) for an adult male and three females differed greatly from comparative data for the holotype of C. schmidti collected at Lake Tickamaya, Honduras (Sissom, 1995). Armas (1996) also described C. sissomi, and assigned it to the thorellii group due to its small size. Illustrations and photographs of the holotype female of C. sissomi in the original description indicate that the pectinal plate is not lobed, and subsequent photographs of the holotype by Armas (2006) indicate a densely granular tegument, characters inconsistent with the “thorellii” clade. Material examined during the present study confirmed the presence of two sympatric species of Centruroides in the Jardín Botánico Alfredo Barrera, Puerto Morelos. One species, determined to be conspecific with the material previously misidentified as C. schmidti by Armas (1996), based on meristic data, is a hitherto undescribed species, described herein as C. yucatanensis. The other is presumed to be C. sissomi, based on the fact that the pectinal plate is not lobed and the tegument is densely granular, as well as its dark orange coloration and larger size (40 mm). Other records of C. schmidti and/or C. sissomi from the Yucatán Península (Vázquez, 1999; Teruel et al., 2015a; Ponce-Saavedra and Francke, 2019) are misidentifications of C. yucatanensis.

Material Examined: MEXICO: Quintana Roo: Município Benito Juárez: Puerto Morelos, Jardín Botánico Alfredo Barrera, 20°50′42.1″N 86°54′12.9″W, 38 m, 4.vii.2007, G. Montiel, R. Paredes, M. Ramírez, D. Chibras, and G. Bonilla, 1 ♂ (AMNH [LP 7597]), 2 juv. ♂ (CNAN SC3984). Yucatán: Município Felipe Carrillo Puerto: Cenote Chac-ha, 3.5 km N and 3 km E of Kalacmul, 20°04′40.3″N 88°08′27.9″W, 23 m, 9.vii.2007, R. Paredes, D. Chibras, and G. Montiel, 1 ♀ (CNAN SC4004).