Eutarsopolipus obrieni sp. nov. (Acari: Podapolipidae), subelytral parasite of Platynus darlingtoni van Emden (Coleoptera: Carabidae), collected in Jamaica, is described. Relationships in the groups of Eutarsopolipus withadult females without stigmata, the pterostichi, brettae, stammeri and lukoschusi groups, are presented and a key to the 12 species in this cluster of Eutarsopolipus is included.
Mites in the family Podapolipidae (Acari: Tarsonemoidea) are primarily parasites of Blattodea, Coleoptera and Orthoptera. Exceptions include Cydnipolipus miyamotoi Kurosa and Husband 1994, which has been collected in Japan from Aethus indicus (Westwood) (Heteroptera: Cydnidae), and Locustacarus buchneri, a widely distributed parasite on many species of Bombus (Hymenoptera: Apidae). Many genera are host-specific at the family level. For example, all of the Chrysomelobiaspecies have hosts in the beetle family Chrysomelidae except the single specimen of Chrysomelobia donati Haitlinger 1989 from an African Homoptera (Seeman 2008). Likewise, all of the 70 species of Eutarsopolipus are parasites of carabid beetles.
Regenfuss (1968) divided the genus Eutarsopolipus into seven groups, and further species groups have been proposed since (Husband & Husband 2009). Constantine and Seeman (2014) describe new species in the ochoai group, hypothesized to be the sister group of the 13 other groups of Eutarsopolipus. Four of the current 13 groups are without stigmata in adult females: pterostichi, brettae, stammeri and lukoschusi groups. The pterostichi group contains eight species: E. pterostichi Regenfuss 1968, E. vernalis Regenfuss 1968, E. inermis Regenfuss 1974, E. diunculosus Eidelberg 1994, E. fischeri Husband 1998, E. shepleyi Husband 2007, E. teteri Husband and Husband 2009 and E. osunaharae Husband and Kurosa 2012. The new species described herein is in the brettae group characterized by the presence of genua I, II, III setae, prominent claws and idiosomal plates in contrast to the stammeri group without claws or plates. The lukoschusi group is without genua I, II, III setae and has a small claw I and minute claws II, III. The new species described herein is from the genus Platynus which is the host genus for two other species of the pterostichi species group. The host of E. teteri is Platynus teter, collected in Mexico, and E. jamaicaensis Husband and Husband 2011 is described from P. punctus (Darlington) from Jamaica. The new species is also from Jamaica.
On a broader scale, E. jamaicaensis is the only other species of Eutarsopolipus known from Jamaica, but it is a member of the biunguis group, which is characterized by adult females with stigmata and trachea, males with genital capsules with concave lateral margins, and larval females with conspicuously separated setae h1. The carabid beetle genus Platynus is also host to another member of the biunguis species group, i.e. E. platyni Husband and Husband 2002, collected in Western North America, making four species and three groups of Eutarsopolipus with Platynus hosts. Keys to groups of Eutarsopolipus and to seven species of the pterostichi group were provided by Husband and Husband (2009). It is the purpose of this paper to describe a new species of Eutarsopolipus parasitic on Platynus darlingtoni in Jamaica, compare the species with a previously described species in the brettae group and present a key to the 12 species in the pterostichi, brettae., stammeri and lukoschusi groups which share the character no stigmata.
Methods and materials
In the process of examining species of the genus Platynus (Carabidae) in the collection of the University of Michigan Museum of Zoology for ectoparasitic mites, Platynus darlingtoni examined by the senior author from St Andrew Parish, Jamaica yielded all instars of a new species of Eutarsopolipus from the dorsal meso and metathorax under the elytra near wing bases. Mites were placed in 70% ethanol and later mounted on glass slides in modified Hoyer's medium for detailed studies. Measurements in micrometers (µm) were taken with the aid of a Zeiss (Jena, Germany) compound phase microscope with an ocular micrometer. Setae no longer than the diameter of the acetabulum are denoted as microsetae (m). If no remnant of a seta exists in the acetabulum, setae are designated as vestigial (v). The terminology follows Lindquist (1986). Often long setae are obscured, bent, entangled or at an angle which makes measurement difficult. Setae are at least as long as indicated.
Differential diagnosis. Adult female E. obrieni without stigmata or trachea, cheliceral stylets (62) shorter than stylets of E. brettae (85), longer than stylets of E. stammeri (29) and E. lukoschi (37), longer than all species in the pterostichi group (29–48) except stylets (75) of E. osunaharae. Adult female E. osunaharae lack ambulacra I, II, III claws. Adult females of E. obrieni have strong ambulacral claws. Gnathosomal setae ch (30) 1½ times longer than setae su (20). All instars with genua I, II, III setae l' and without coxal seta 3a. Male with genital capsule longer than wide, with straight lateral margins. Gnathosomal setae ch (9) nearly ½ length of setae su (17), ambulacra II, III with two thin claws, prodorsal plate setae sc2 60, remaining idiosomal setae v-m. Larval female ambulacrum I with two claws, ambulacra II, III each with two claws 10, setae h1 adjacent or nearly so, plate C setae c2 (13) nearly in line with and slightly longer than setae c1 (10). Setae v1 (30) longer than ½ width of gnathosoma (39).
Female (Figs. 1, 2, n=4): Gnathosoma length 60–62, width 50–52 (Table 1). Palp length 16– 18, cheliceral stylets length 62, pharynx width 15–17, dorsal gnathosomal setae ch 28–30, setae su 20. Distance between setae su–su 20–22. Coxal setae 1a, 2a, 3b 7–8, in midcoxal positions, not near apodemes I, II, III.
Idiosoma. Length 550, width 350. No stigmata. Prodorsal plate length 90, width 160, setae v1 10, v2 v, sc1 10, sc2 45. Distance v1–v1 26, sc2–sc2 122. Plate C length 70, width 170, setae c1 10, c2 11. Plate EF length 62, width 113, setae e m, no setae h.
Legs. Ambulacrum I with a single thick claw 15 and sucker, ambulacra II, III with two thick claws 10. Femur I v” 18, genua I, II, III v' 5, tarsus I solenidion ω midtarsus 5, tc' 18, tc” 15, pl” 20. Tibia I solenidion ϕ 9, adjacent seta k 5. Tarsus II ω 5. Tibiae I, II, III setae d 40, 22, 20 respectively, tarsus III setae pl” 21. Setae per segment on femur, genu, tibia and tarsus of legs I, II, III, respectively: 2-1-7-8, 0-1-4-6, 0-1-4-5.
Male (Figs. 3, 4, n=3): Gnathosoma length 30–32, width 29–32. Palp length 10–12, cheliceral stylet length 30, pharynx width 10. Dorsal gnathosomal seta ch 8–9, ventral setae su 14–17, distance between su–su 15.
Idiosoma. Length 168–180, width 113–142. Prodorsal plate length 70, width 122. Setae v1, sc1 m, sc2 52–60, distance v1–v1 34. Setae c1, c2, d and e microsetae or vestigial. Genital capsule length 36–45, width 30–36, lateral margins straight. Venter with apodemes weakly developed,apodemes II not reaching sternal apodeme medially. Coxal setae 1a, 2a, 3b each 2–3.
Legs. Femur I seta d v, setae v” 13. Tibia I seta d 30, solenidion ϕ 8, tarsus I solenidion ω 5. Tibia II seta d 13, tarsus II solenidion ω 5. Tibia III seta d 13, tarsus III seta pl” 12. Ambulacrum I with one claw, ambulacra II, III with two small claws 5. Setae per leg segment of legs I, II, III as in adult female.
Larval female (Figs. 5, 6, n=4): Gnathosoma length 38–42, width 15–20. Palp length 13–18, cheliceral stylet length 41–52, pharynx width 12–16. Dorsal gnathosomal seta ch 22–32, ventral seta su 15–20. Distance between su–su 10–14.
Idiosoma. Length 186–310, width 129–222. Prodorsal plate length 78, width 102. Seta v1 25–30, sc1 thin 10–20, sc2 77–84, distance between v1–v2 31. Setae c1 7–10, c2 10–13. Setae c1 in line with setae c2 on fused plates CD, setae d 4. Plate EF length 29, width 50, setae e 10. Plate H length 19, width 25, setae h1 100, h2 5. Venter with apodemes weakly developed, apodemes II not reaching sternal apodeme medially. Coxal setae 1a 6–7, 2a 4–5, 3b 4.
Legs. Femur I d m, v” 18, genu l' 3, tibia I d 45, solenidion ϕ 10, seta k 9. Tarsus I solenidion ω 6, tc' 12, tc” 12', pl' 10, pl” 15, pv' and pv” 3. Tibia II seta d 15, tarsus II solenidion ω 8. Tibia III seta d 18, tarsus III seta pl''23. Ambulacra I with two thin claws, ambulacra II, III each with two thin claws. Setae per leg segment of legs I, II, III as in adult female.
Egg (n=2): Length 228–249, width 118–142.
Etymology. Eutarsopolipus obrieni is named for Mark O'Brien, collection manager of the entomology collection of the University of Michigan Museum of Zoology, in recognition of his many years of substantial aid with acquiring access to, and providing answers to questions about, insects in the collection at UMMZ.
Type material: Holotype, adult female (RWH220310-10), from Platynus darlingtoni van Emden (Coleoptera: Carabidae), vicinity of Cinchona, St. Andrew Parish, Jamaica, British West Indies, 15 June 1948, coll. D. E. Miller, deposited in the University of Michigan Museum of Zoology, Ann Arbor, Michigan, U.S.A. Paratypes, three females (three slides), three males, four larval females, one slide with eggs and a larval female with same data as holotype. One adult female, one male and one larval female are deposited at the National Museum of Natural History, Washington D. C., U.S.A. The remaining paratypes are deposited with the holotype at UMMZ.
Comparison of selected maximum measurements for species of the pterostichi and brettae groups of Eutarsopolipus: E. obrieni ( Eob), E. osunaharae (Eos), E.inermis (Ei), E. pterostichi (Ep) E. teteri (Et), E. fischeri (Ef), E. shpeleyi (Es), E. diunculosus (Ed) and E. brettae (Eb). All measurements are in micrometers (µm).
The pterostichi group of Eutarsopolipus was reviewed by Husband and Husband (2009). This publication provided keys to groups of Eutarsopolipus, provided keys to species within the pterostichi group and pointed out difficulties in placing new species in the group as defined by Regenfuss (1968). Regenfuss (1974) added E. inermis to the pterostichi group. Adult females of E. inermis lack ambulacra I, II, III claws. Husband and Kurosa (2012) added E. osunaharae, which also has adult females without claws, and included a revised key to species in the pterostichi group. All species in the pterostichi, stammeri, lukoschusi and brettae groups have adult females without stigmata.
Adult female E. obrieni have long femur I setae v” (18) in common with females of E. brettae (14) and E. lukoschusi (10) and in contrast to femur I v” (0) in E. stammeri and 0–3 in all species in the pterostichi group except E. teteri (15) (Table 1). Stylets of E. obrieni (62) are shorter than stylets of E. brettae (85) and E. osunaharae (75) but longer than remaining species in the pterostichi group (25–48) or E. stammeri (29) and E. lukoschusi (37). Gnathosomal setae ch exceed 25 only in E. obrieni (30), E. brettae (35) and E. inermis (28). Idiosomal setae c1 (10) are longer than c1 setae in E. inermis (5) or E. brettae (7–8) . Two thin claws are present on ambulacra II, III of male E. obrieni (5), E. brettae (4), E. lukoschusi (m) as well as E. teteri (5) and E. fischeri (2) but not present in remaining species in the pterostichi group. Gnathosomal setae ch are longer in males of E. obrieni(9), E. inermis (12) and E. pterostichi (16) than in the remaining species in the pterostichi group (m-5) and in male E. brettae (4), E. stammeri (2) and E. lukoschusi (6). The genital capsule is distinctly longer than wide in males of E. obrieni (45/36), E. teteri (38/32) and E. fischeri (38/30) but wider than long in E. stammeri. The lateral margins of the genital capsule of all males in the pterostichi group as well as the genital capsule of E. obrieni are straight. The genital capsules of males of E. brettae and E. lukoschusi are concave laterally. Cheliceral stylets of larval female E obrieni (52), E. brettae (64), E. osunaharae (48) and E. inermis (49) exceed 45 micrometers in contrast to lengths of stylets 12–34 in larval females of the remaining species in the pterostichi group as well as stylets of larval E. lukoschuri (21) and E. stammeri (19). Idiosomal setae v1 of larval females of E. obrieni (30), E. brettae (20) and E. teteri (10) are longer than in remaining species in the pterostichi group (0–5) and in larval females of the lukoschusi (8) and stammeri (8) groups.
As many new species of Eutarsopolipus are discovered and described from many of the 34,275 species of Carabidae (Lorenz, 2005), groups of the current 70 species of Eutarsopolipus will be revised in the future.
Key to adult females of Eutarsopolipus without stigmata
1 With one ambulacrum I claw 2
- With two ambulacrum I claws, host genus Dyschirius, Moldova, Ukraine Eutarsopolipus diunculosus Eidelberg
2 Without coxal seta 3a 3
- With coxal seta 3a 5
3 Cheliceral stylets less than 65 4
- Cheliceral stylets 85, host genus Agonum, Galapagos Islands Eutarsopolipus brettae Husband
4 Cheliceral stylets 62, , gnathosomal setae ch (30) 1 ½ longer than su (20), host genus Platynus, St. Andrew Parish, Jamaica. Eutarsopolipus obrieni Husband and Husband sp. nov.
- Cheliceral stylets 38, originating in mid gnathosoma, gnathosomal setae ch (15) nearly equal to setae su(14), host genus Platynus, Chiapas, Mexico Eutarsopolipus teteri Husband and Husband
5 With plates C, D, with femur I setae 6
- Without plates C, D, without femur I setae, host genus Pterostichus, Ebermannstadt, Germany Eutarsopolipus stammeri Regenfuss
6 Ambulacra I, II, III with claws 7
- Ambulacra I, II, III without claws, host genus Evarthrus, Georgia, U. S. A. Eutarsopolipus inermis Regenfuss
7 Setae c1 mid to posterior on plate C, sc2 short to long, ambulacra I claws as long as or longer than spine-like tarsi I setae s. 8
- Setae c1 near anterior border of plate C, sc2 12, ambulacra claws I shorter than spine-like tarsi setae s, host genus Thermophilum, South Africa Eutarsopolipus lukoschusi Husband
8 Cheliceral stylets shorter than 70 (25–62) 9
- Cheliceral stylets 75, longer than width of gnathosoma (48), gnathosomal setae ch short (6), setae h 5, host genus Diplocheila, Chiba and Fukuoka Prefectures, Japan Eutarsopolipus osunaharae Husband & Kurosa
9 Setae h1 (0–4) shorter than ½ distance between setae h1 (12–25) 10
- Setae h1 (15–16) nearly equal to distance between setae h1 (15–21), host genus Pterostichus, Germany, Hungary, Poland, Russia, Ukraine Eutarsopolipus pterostichi Regenfuss
10 Dorsal gnathosomal setae ch (10), two times length of ventral gnathosomal setae su (5) 11
- Dorsal gnathosomal setae ch (19) three times length of ventral gnathosomal setae su (6), host genus Harpalus, Michigan, U. S. A. Eutarsopolipus fischeri Husband
11 Plate C setae c1 (10) 1/2 width of base of tarsus I, host genus Pterostichus, Germany, Ukraine Eutarsopolipus vernalis Regenfuss
- Plate C setae c1 (4) less than ½ width of base of tarsus I, host genus Pterostichus, Michigan, U.S.A Eutarsopolipus shpeleyi Husband
We thank Barry M. OConnor and Mark O'Brien, University of Michigan Museum of Zoology, for providing carabid beetles for examination for mites and for useful comments, Timothy Husband, Siena Hts. University for technical support and anonymous reviewers for useful suggestions for improving the manuscript.