Pediculaster tjumeniensis Khaustov 2020, sp. nov.

Pediculaster tjumeniensis sp. nov.

Zoobank: 9C126801-3491-4277-8757-9C9AE42FB5BD

(Figs 1–9A)

Description

Phoretic female (Figs 1–3, 9A) — Length of idiosoma 265 (200–305), width 140 (105– 160).

Gnathosoma (Figs 1, 9A) – Length of gnathosomal capsule 26 (23–27), width 29 (28–32). Dorsal median apodeme weakly developed. All gnathosomal setae pointed; setae cha, chb and dFe with few very small barbs, other gnathosomal setae smooth. Palp tibiotarsus with welldeveloped blunt-tipped claw and tiny eupathid-like seta; palps ventrally with well-developed solenidion and mushroom-shaped accessory setigenous structure. Php 1 small, bow-shaped, located inside gnathosomal capsule; php 2 and 3 oval (Fig. 9A), situated close to each other on long oesophagus and far separated from php 1. Lengths of gnathosomal setae: cha 10 (8–12), chb 14 (10–15), dFe 13 (9–13), dGe 18 (12–18), m 16 (11–16).

Idiosomal dorsum (Fig. 1A) – All dorsal shields with numerous small round dimples. Stigmata small, oval, one-chambered and associated with long tracheal trunks. All dorsal setae blunt-ended and barbed; trichobothria sc 1 short, spherical. Cupules ia on tergite D and ih on tergite H very small, round. Lengths of dorsal setae: v 1 29 (22–29), v 2 30 (25–32), sc 2 57 (43–58), c 1 40 (29–40), c 2 48 (35–52), d 43 (32–45), e 24 (17–24), f 45 (30–45), h 1 37 (27–38), h 2 14 (10–16). Distances between setae: v 1 – v 1 10 (10–12), v 2 – v 2 31 (26–32), sc 2 – sc 2 46 (41–53), c 1 – c 1 44 (33–49), c 1 – c 2 30 (21–34), d–d 73 (52–78), e–f 21 (15–23), f –f 45 (32–51), h 1 – h 1 51 (34–52), h 1 – h 2 18 (14–19).

Idiosomal venter (Fig. 1B) – Ventral plates with numerous small round dimples. Setae 1 b and 2 a pointed; other ventral setae blunt-ended; setae ps 1 and ps 3 smooth, over ventral setae weakly barbed; setae 2 a much longer than other ventral setae; in one specimen left seta 2 c abnormally long and pointed. Ap1, ap2 and apsej well developed and joined with appr; ap3 and ap4 well developed and joined with appo; ap5 weaker sclerotized than other apodemes and joined with appo. Posterior margin of poststernal plate evenly rounded, without median lobe. Anterior and posterior genital sclerites long and narrow; median genital sclerite small, oval. Lengths of ventral setae: 1 a 19 (15–19), 1 b 26 (18–29), 1 c 17 (14–17), 2 a 43 (38–48), 2 b 18 (4–19), 2 c 16/20 (14–17), 3 a 18 (14–20), 3 b 16 (13–17), 3 c 19 (14–21), 4 a 16 (12–17), 4 b 19 (15–22), 4 c 18 (13–20), ps 1 8 (5–8), ps 2 26 (17–27), ps 3 7 (4–9).

Legs (Figs 2, 3) – Leg I (Fig. 2A). Leg setation: Tr v’) 1, (Fe 4 (d, l’, l”, v”), Ge 4 (l’, l”, v’, v”), TiTa 17(4) (d, l’, l”, v’, v”, k, pl’, pl”, p’, p”, tc’, tc”, ft’, ft”, s, pv’, pv”, ω 1, ω 2, φ 1, φ 2). Tibiotarsus slightly thickened, distinctly wider than genu. Lengths of solenidia ω 1 14 (11–14), ω 2 11 (9–11), φ 1 9 (7–9), φ 2 9 (8–10); solenidion φ 1 slightly clavate, other solenidia finger-shaped. Setae p (), (tc) and (ft) eupathid-like; seta d of femur smooth, spatulate distally; seta k of tibiotarsus smooth and weakly blunt-ended; setae l’ of femur and (l) of genu blunt-ended and barbed; other leg setae (except eupathidia) pointed and barbed. Leg II (Fig. 2B). Leg setation: Tr 1 (v’), Fe 3 (d, l’, v”), Ge 3 (l’, l”, v’), Ti 4(1) (d, l’, v’, v”, φ), Ta 6(1) (pl”, tc’, tc”, pv’, pv”, u’, ω). Solenidia ω 9 (7–9) and φ 5 (4–5) finger-shaped. Tarsal claws with thickened basal half; empodium long and narrow, with widened tip. All leg setae barbed; setae d, l’ of femur and u’ of tarsus blunt-ended, other leg setae pointed. Leg III (Fig. 3A). Leg setation: Tr 1 (v’), F2 3 (d, v’), Ge 2 (l’, v’), Ti 4(1) (d, l’, v’, v”, φ), Ta 6 (pl”, tc’, tc”, pv’, pv”, u’). Claws and empodium as on tarsus II. Solenidion φ 4 (3–4) weakly clavate. All leg setae barbed; setae d, v’ of femur and l’ of genu blunt-ended, other leg setae pointed. Leg IV (Fig. 3B). Leg setation: Tr 1 (v’), Fe 2 (d, v’), Ge 1 (v’), Ti 4(1) (d, l’, v’, v”, φ), Ta 6 (pl”, tc’, tc”, pv’, pv”, u’). Claws simple, hooked, empodium narrower than on tarsi II and III. Solenidion φ 3 (2–3) rod-like. All leg setae barbed; seta v’ of femur blunt-ended, other leg setae pointed.

Non-phoretic female (Figs 4–6) — Length of idiosoma 240–300, width 125–150.

Gnathosoma (Fig. 4) – Length of gnathosomal capsule 27–31, width 33–38. Gnathosoma and pharyngeal pumps in general as in phoretic female, but cheliceral setae and seta dFe smooth. Lengths of gnathosomal setae: cha 9–11, chb 14–15, dFe 13–14, dGe 15–16, m 17–19.

Idiosomal dorsum (Fig. 4A) – as in phoretic female, but dorsal sclerites weaker sclerotized and dimples smaller, difficult to discern. Lengths of dorsal setae: v 1 19–23, v 2 19–24, sc 2 37–44, c 1 26–31, c 2 39–44, d 28–36, e 15–20, f 27–39, h 1 23–33, h 2 6–8. Distances between setae: v 1 – v 1 11–12, v 2 – v 2 28–32, sc 2 – sc 2 29–33, c 1 – c 1 40–45, c 1 – c 2 25–34, d–d 61–70, e–f 16–18, f –f 42–45, h 1 – h 1 45–49, h 1 – h 2 14–15.

Idiosomal venter (Fig. 4B) – similar to that of phoretic female, but plates weaker sclerotized and dimples smaller; setae 2 a normally not very long and blunt-ended, and only in one specimen left seta 2 a long and pointed and similar to that of phoretic female. Apsej indistinct; ap5 stronger sclerotized than in phoretic female. Lengths of ventral setae: 1 a 13–15, 1 b 13–18, 1 c 11–15, 2 a 14–33, 2 b 12–16, 2 c 10–13, 3 a 14–18, 3 b 13–17, 3 c 14–18, 4 a 12–15, 4 b 13–18, 4 c 14–15, ps 1 6, ps 2 17–22, ps 3 4–5.

Legs (Figs 5, 6) – Leg I (Fig. 5A). Tibia and tarsus separated. Tarsal claw simple, hooked. Leg setation: Tr 1 (v’), Fe 4 (d, l’, l”, v”), Ge 4 (l’, l”, v’, v”), Ti (6)(2) (d, l’, l”, v’, v”, k, φ 1, φ 2), Ta 13(2) (pl’, pl”, p’, p”, tc’, tc”, ft’, ft”, s, pv’, pv”, u’, u”, ω 1, ω 2). Lengths of solenidia ω 1 16–19, ω 2 13–15, φ 1 6–8, φ 2 10–11; solenidion φ 1 clavate, other solenidia finger-shaped. Setae (p), (tc) and (ft) eupathid-like; seta k of tibiotarsus smooth and weakly blunt-ended; other leg setae (except eupathidia) pointed and barbed. Leg II (Fig. 5B). Leg setation: v’ Tr), 1 (Fe 3 (d, l’, v”), Ge 3 (l’, l”, v’), Ti 4(1) (d, l’, v’, v”, φ), Ta 7(1) (pl”, tc’, tc”, pv’, pv”, u’, u”, ω). Solenidia ω 11–12 and φ 8–9 finger-shaped. Tarsal claws simple, hooked; empodium short and wide. All leg setae barbed; seta l’ of femur blunt-ended, other leg setae pointed. Leg III (Fig. 6A). Leg setation: Tr 1 (v’), Fe 2 (d, v’), Ge 2 (l’, v’), Ti 4(1) (d, l’, v’, v”, φ), Ta 7 (pl”, tc’, tc”, pv’, pv”, u’, u”). Claws and empodium as on tarsus II. Solenidion φ 6–7 finger-shaped. All leg setae barbed; seta v’ of femur blunt-ended, other leg setae pointed. Leg IV (Fig. 6B). Leg setation: Tr 1 (v’), Fe 2 (d, v’), Ge 1 (v’), Ti 4(1) (d, l’, v’, v”, φ), Ta 6 (pl”, tc’, tc”, pv’, pv”, u’). Claws and empodium as on tarsi II and III. Solenidion φ 3–4 rod-like. All leg setae barbed; seta v’ of femur blunt-ended, other leg setae pointed.

Larva (Figs 7, 8) — Length of idiosoma 195–215, width 105–115.

Gnathosoma (Figs 7, 8) – Length of gnathosomal capsule 27–30, width 31–34. Cheliceral setae cha short and thick, other gnathosomal setae smooth and pointed; setae chb absent.

Dorsal median apodeme absent. Accessory setigenous structure distinctly shorter than palpal solenidion. Subcapitulum with two pairs of setae (m, n). Lengths of gnathosomal setae: cha

3–4, dFe 9–10, dGe 12–14, m 14–15, n 10–11. Pharyngeal pumps 2 and 3 as in female, php 1 small, bow-shaped and situated on the short distance from php 2 inside propodosoma.

Idiosomal dorsum (Fig. 7A) – Prodorsum with one trapezium-shaped shield with four pairs of setae; tergite C divided into three plates, one median with one pair of setae c 1 and two laterals with setae c 2; tergites D, EF and H with same number of setae as in females. All dorsal setae strongly barbed; setae h 1 and h 2 pointed, other dorsal setae blunt-ended. Tergites D and H with small round cupules ia and ih, respectively. All dorsal shields with small round dimples. Lengths of dorsal setae: v 1 14–18, v 2 12–16, sc 1 21–29, sc 2 30–35, c 1 23–26, c 2 25–31, d 25–33, e 18–23, f 29–35, h 1 28–35, h 2 59–63. Distances between setae: v 1 – v 1 9–11, v 2 – v 2 41–45, sc 1 – sc 1 28–29, sc 2 – sc 2 49–53, c 1 – c 1 40–42, d–d 43, e–f 11–12, f –f 33–34, h 1 – h 1 12–14, h 1 – h 2 10–11.

Idiosomal venter (Fig. 7B) – Coxal fields I-III separated medially and with two pairs of setae each. Ap1, ap2 and ap3 well developed; other apodemes absent. All ventral setae barbed; setae ps 1-3 pointed, other ventral setae blunt-ended. Lengths of ventral setae: 1 a 11–13, 1 b 11–13, 2 a 12–13, 2 b 12–14, 3 a 15–20, 3 b 12–16, ps 1 14–16, ps 2 17–20, ps 3 18–20.

Legs (Fig. 8) – Leg I (Fig. 8A). Tarsus with two simple hooked claws; empodium absent. Leg setation: Tr 0, Fe 4 (d, l’, l”, v”), Ge 4 (l’, l”, v’, v”), Ti (6)(1) (d, l’, l”, v’, v”, k, φ 1), Ta 11(1) (pl’, pl”, tc’, tc”, ft’, ft”, s, pv’, pv”, u’, u”, ω 1). Lengths of solenidia ω 1 10–14, φ 1 7–9; solenidion ω 1 finger-shaped; solenidion φ 1 clavate. Setae (tc) eupathid-like; seta k of tibiotarsus smooth and weakly blunt-ended; setae l’ of femur and v’ of genu blunt-ended and barbed, other leg setae (except eupathidia) pointed and barbed. Leg II (Fig. 8B). Leg setation: Tr 0, Fe 3 (d, l’, v”), Ge 3 (l’, l”, v’), Ti 4(1) (d, l’, v’, v”, φ), Ta 7(1) (pl”, tc’, tc”, pv’, pv”, u’, u”, ω). Solenidia ω 8–10 and φ 4–5 finger-shaped. Tarsal claws simple, hooked; empodium short and wide. Seta l’ of femur smooth and blunt-ended; seta v’ of genu barbed and blunt-ended, other leg setae pointed and barbed. Leg III (Fig. 8C). Leg setation: Tr 0), F d, 2 3 (v’), Ge 2 (l’, v’), Ti 4 (d, l’, v’, v”), Ta 7 (pl”, tc’, tc”, pv’, pv”, u’, u”). Claws and empodium as on tarsus II. Solenidion φ absent. Seta pl” of tarsus spine-shaped, smooth; setae d, v’ of femur and l’ of genu blunt-ended and barbed, other leg setae pointed and barbed. Femur not divided into basi- and telofemur.

Male unknown.

Type material — Phoretic female holotype slide ZISP T-Pygm-004: Russia, Tyumen Province, Tyumen, “Zatyumenskiy park”, 57°09’ N, 65°26’ E, in the rotting log of birch, 21 April 2019, A.A. Khaustov leg. Paratypes: 7 phoretic females, same data as holotype; 4 phoretic and 4 non-phoretic females, same locality and collector, 10 July 2019; 2 phoretic females and 7 larvae, same locality and collector, 26 April 2019.

Type deposition — The holotype and 4 phoretic females paratypes are deposited in the collection of the Zoological Institute of RAS, Saint Petersburg, Russia; other paratypes are deposited in the mite collection of the Tyumen State University Museum of Zoology, Tyumen, Russia.

Etymology — The name of the new species refers to its distribution in Tyumen city, the capital of Tyumen Province, Russia.

Differential diagnosis — Phoretic female of the new species is most similar to P. sellnickianus (Rack, 1964) and P. limosinae Samsinak, 1984 (not separable morphologically from P. sellnickianus) by the presence of three pairs of setae on coxal fields I and II, setae ps 2 longer than ps 3, and setae 2 a much longer than b 2. The new species can be distinguished from P. sellnickianus by having setae c 2 clearly longer than c 1 (setae c 1 and c 2 subequal in P. sellnickianus), by the presence of ap5 (ap5 absent in P. sellnickianus), and setae e no more than twice longer than h 2 (setae e more than 3 times longer than h 2 in P. sellnickianus). Non-phoretic female of the new species is most similar to P. permagnus (Rack, 1971) but can be distinguished from it by longer distance between setae e and f, which less than 3 times shorter than distance f-f (e-f about 4 times shorter than f-f in P. permagnus), by solenidion φ 2 distinctly longer than φ 1 (solenidia φ 2 and φ 1 subequal in P. permagnus), and by much longer solenidion ω 2, which reaching far beyond the base of solenidion ω 1 (solenidion ω 2, much shorter and not reaching base of solenidion ω 1 in P. permagnus). Larva of the new species can be distinguished from all described larvae of Pediculaster by the presence of setae n on subcapitulum (setae n absent in all described larvae of Pediculaster).