Two new species of the genus Pediculaster (Acari: Pygmephoridae) from Western Siberia, Russia Author Khaustov, Alexander A. text Zootaxa 2015 3926 3 413 429 journal article 10.11646/zootaxa.3926.3.6 034b869f-e50a-4a37-b796-61f8ce01dea9 1175-5326 245190 99FA3324-570F-420A-83C8-AB8A6B200507 Pediculaster ermilovi Khaustov sp. nov. ( Figs. 1–7 ) Description . PHORETIC FEMALE ( Figs. 1–4 ). Length of idiosoma 240, width 130. FIGURE 1 . Pediculaster ermilovi Khaustov sp. nov . , phoretic female, idiosoma: A—dorsum, B—venter. FIGURE 2 . Pediculaster ermilovi Khaustov sp. nov . , phoretic female: pharyngeal pumps. Gnathosoma ( Figs. 1 , 2 ). Gnathosomal capsule slightly widened distally, dorsally with 2 pairs of simple setae. Setae cha (9) slightly shorter than chb (10). Dorsal median apodeme present. Ventrally gnathosoma with 1 pair of subcapitular setae m (10). Palps freely articulated to gnathosomal capsule, with setae dFe and dGe dorsolaterally. Setae dGe slightly longer than dFe . Palpal tibiotarsus ventrally with large accessory setigenous structure ( ass ) and well-developed solenidion. Palps terminated with a small claw. Pharyngeal pump I small, situated on the level of posterior margins of trochanters I; pharyngeal pumps 2 and 3 well-developed, subequal in length, situated closely to each other ( Fig. 2 ). Idiosomal dorsum ( Fig. 1 A). Prodorsum with 3 pairs of setae, a pair of smooth capitate trichobothria, and one pair of oval one-chambered stigmata. All dorsal shields with numerous small dimples. Setae h 2 small, smooth, needle-like, other dorsal setae distinctly barbed and blunt-ended. Cupules ia on tergite D and ih on tergite H large, round. Cupules im on tergite EF not evident. An unusualy large well-sclerotized projection present inside body, beginning at posterior margin of body and reaching almost level of setal bases h 1. Lengths of dorsal setae: v 1 20 , v 2 12 , sc 2 49, c 1 41, c 2 40, d 41, e 18, f 50, h 1 52, h 2 5. Distances between setae: v 1– v 1 8 , v 2 –v 2 24 , sc 2 –sc 2 26, c 1– c 1 39, c 1– c 2 22, d–d 72, e–f 12, f–f 57, h 1– h 1 54, h 1– h 2 9. Idiosomal venter ( Fig. 1 B). All ventral plates with numerous small dimples. All setae of anterior and posterior sternal plates smooth, needle-like. Setae ps 2 barbed, blunt-ended. Setae ps 1 and ps 3 subequal, blunt-ended, ps 1 displaced distinctly anteriorly from bases of setae ps 2 and ps 3. Setae 1 c and 2 c absent. Apodemes 1 (ap1) and apodemes 2 (ap2) well developed and joined with prosternal apodeme (appr); appr and sejugal (apsej) apodemes well developed; apodemes 3 well developed, arch-like. Apodemes 4 (ap4) well developed and long, apodemes 5 present, reaching posteriad bases of setae 4 a , weakly sclerotized. Posterior margin of posterior sternal plate with lobe in medial part. Posterior margin of aggenital plate almost v-shaped. Genital sclerite unusually small, bell-like, situated close to posterior margin of posterior sternal plate. Length of ventral setae: 1 a 12, 1 b 12, 2 a 15, 2 b 11, 3 a 10, 3 b 10, 3 c 14, 4 a 11, 4 b 14, 4 c 16, ps 1 4, ps 2 17, ps 3 4. FIGURE 3 . Pediculaster ermilovi Khaustov sp. nov . , phoretic female: A—leg I, B—leg II. Legs ( Figs. 3 , 4 ). Leg chaetotaxy typical for the genus, except the absence of setae v’ on trochanter IV. Leg I ( Fig. 3 A). Tibiotarsus cylindrical, tarsal claw terminal. Length of solenidia ω 1 8> ω 2 3 < φ 1 8> φ 2 4; ω 2 and φ 2 baculiform, φ 1 clavate, ω 1 finger-shaped. Seta dFe spatulate distally. Seta k unusually long and pointed. Setae l’ , l” of genu, l’ of femur and v’ of trochanter blunt-ended. Leg II ( Fig. 3 B). Tarsus with padded claws bifurcated at the tips and well-developed tongue-like empodium. Solenidion ω (5) finger-shaped, solenidion φ (4) weakly clavate. Setae v’ of trochanter, u’ of tarsus and all setae of femur blunt-ended. Leg III ( Fig. 4 A). Claws of same shape as on tarsus II. Solenidion φ (4) weakly clavate. Setae v’ of trochanter, u’ of tarsus and all setae of femur blunt-ended. Femur divided into basi- and telofemur. Leg IV ( Fig. 4 B). Tarsal claws simple, empodium small. Solenidion φ (3), weakly clavate. Setae of femur blunt-ended. Femur divided into basi- and telofemur. NON-PHORETIC FEMALE ( Figs. 5 , 7 ). Length of idiosoma 190–240 in 7 patratypes, width 120–140. Gnathosoma and pharyngeal pumps as in phoretic female. Length of setae: cha 8–12, chb 9–12, m 8–9. Idiosomal dorsum ( Fig. 5 A). Similar with that of phoretic female, but dorsal setae v 1 shorter, subequal with v 2. Lengths of dorsal setae: v 1 12 –17, v 2 11 –14, sc 2 23–33 , c 1 20–30 , c 2 21–31 , d 24–30, e 11–13, f 23–33, h 1 28–34 , h 2 4–5. Distances between setae: v 1– v 1 6–7 , v 2 –v 2 18–23 , sc 2 –sc 2 19–22 , c 1– c 1 35–37, c 1– c 2 19–24 , d–d 61–73, e–f 6–11, f–f 50–64, h 1– h 1 47–57, h 1– h 2 5–8. FIGURE 4 . Pediculaster ermilovi Khaustov sp. nov . , phoretic female: A—leg III, B—leg IV. FIGURE 5 . Pediculaster ermilovi Khaustov sp. nov . , non-phoretic female, idiosoma: A—dorsum, B—venter. Idiosomal venter ( Fig. 5 B). Similar with that of phoretic female. Lengths of ventral setae: 1 a 8–11, 1 b 9–11, 2 a 10–12, 2 b 8–9, 3 a 8–11, 3 b 8–10, 3 c 11–13, 4 a 8–10, 4 b 10–12, 4 c 10–13, ps 1 3–4, ps 2 11–16 , ps 3 3–4. Legs ( Figs. 6 , 7 ). Leg I ( Fig. 6 A) 5-segmented. Tarsus I tapered distally, with simple sickle-like claw. Setae d of femur I long, not modified. Length of solenidia ω 1 7–10 > ω 2 4–5< φ 1 5–6 = φ 2 5–8; ω 2 and φ 2 baculiform, φ 1 clavate, ω 1 finger-shaped. Setae v’ of trochanter blunt-ended. Leg II ( Fig. 6 B). Tarsus with simple sickle-like claws and well-developed empodium; empodium with distinct incision at the tip. Tarsus II with 7 setae ( u” present). Solenidion ω (5–7), finger-shaped, solenidion φ (3–4) weakly clavate. All setae of femur and v’ of trochanter bluntended. Leg III ( Fig. 7 A). Claws of same shape as on tarsus II. Tarsus III with 7 setae ( u” present). Solenidion φ (3–4) weakly clavate. Setae of trochanter and femur blunt-ended. Leg IV ( Fig. 7 B). Similar to that of a phoretic female. Setae of femur blunt-ended. MALE and LARVA unknown. FIGURE 6 . Pediculaster ermilovi Khaustov sp. nov . , non-phoretic female: A—leg I, B—leg II. Type material . Phoretic female holotype , slide AK 151114 , RUSSIA : Tyumen Province, Tyumen, in rotten log of poplar ( Populus nigra ), 57o09’52.3” N , 65o31’01.6” E , 15 November 2014 , coll. A.A. Khaustov. Paratypes : 7 non-phoretic females, same data. FIGURE 7 . Pediculaster ermilovi Khaustov sp. nov . , non-phoretic female: A—leg III, B—leg IV. Etymology . The new species is named for the Russian acarologist Sergey Ermilov for his contribution to science. Differential diagnosis . The phoretic female of a new species is most similar to P. subarcanus Gao and Zou, 2000 by the absence of setae 1 c and 2 c , presence of apodemes 5, one-chambered stigmata, absence of setae v’ on trochanter IV. It differs from P. subarcanus by the setae e barbed and more than 3 times longer than h 2 (vs. smooth and subequal with h 2 in P. subarcanus ), setae v 1 less than two times longer than setae v 2 (vs. more than 3 times longer than v 2 ), by cylindrical tibiotarsus I (vs. distinctly widened in basal part), and by the presence of setae ps 1 (vs. absent).