Pediculaster lignarius Khaustov

Khaustov, Alexander A., 2015, Two new species of the genus Pediculaster (Acari: Pygmephoridae) from Western Siberia, Russia, Zootaxa 3926 (3), pp. 413-429 : 422-425

Pediculaster lignarius Khaustov sp. nov.

( Figs. 8–11 )

Description. PHORETIC FEMALE ( Figs. 8–11 ). Length of idiosoma 280 (270–300 in 7 paratypes), width 130 (125–140).

Gnathosoma ( Figs. 8–9 ). Gnathosoma similar to that of P. ermilovi sp. nov., but dorsal gnathosomal setae needle-like and dorsal gnathosomal apodeme absent. Setae cha 7 (7–9) subequal to chb 8 (7–8). Setae m 9 (9–10). Pharyngeal pump I small, situated inside gnathosomal capsule; pharyngeal pumps 2 and 3 well-developed, subequal, situated closely to each other ( Fig. 9 ).

Idiosomal dorsum ( Fig. 8 A). Prodorsum with 3 pairs of setae, a pair of smooth capitate trichobothria, and 1 pair of oval one-chambered stigmata. All dorsal shields with numerous small dimples. Setae e and h 2 small smooth, needle-like, other dorsal setae distinctly barbed. Setae c 2 pointed, other dorsal setae blunt-ended. Cupules ia on tergite D and ih on tergite H large, round. Cupules im on tergite EF weakly discernible. Setae e situated distinctly anteriorly to bases of setae f. Setae c 1 situated distinctly anterior to setae c 2. Length of dorsal setae: v 1 27 (26–32), v 2 24 (22–26), sc 2 53 (51–56), c 1 33 (32–42), c 2 58 (55–65), d 39 (38–43), e 7 (7–8), f 42 (42–45), h 1 36 (34–40), h 2 7 (7–8). Distances between setae: v 1– v 1 9 (9–10), v 2 –v 2 19 (18–21), sc 2 –sc 2 34 (33–36), c 1– c 1 46 (45–51), c 1– c 2 25 (23–28), d–d 77 (74–86), e–f 6 (6–8), f–f 76 (76–83), h 1– h 1 66 (65–72), h 1– h 2 5 (5–6).

Idiosomal venter ( Fig. 8 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. Ap1 and ap2 well developed and joined with appr; appr and apsej well developed; ap3 well developed, arch-like. Ap4 well developed and long, ap5 absent. Posterior margin of posterior sternal plate tripartite. Posterior margin of aggenital plate almost v-shaped. Genital sclerite long and narrow, with lateral projection. Lengths of ventral setae: 1 a 10 (10–11), 1 b 14 (14–16), 1 c 13 (12–14), 2 a 14 (12–14), 2 b 14 (13–14), 2 c 9 (8–9), 3 a 12 (11–12), 3 b 10 (10–12), 3 c 15 (14–16), 4 a 11 (11–12), 4 b 16 (1517), 4 c 14 (14–15), ps 1 5 (5–6), ps 2 26 (24–26), ps 3 5 (5–6).

Legs ( Figs. 10–11 ). Leg setation typical for genus. Leg I ( Fig. 10 A). Tibiotarsus cylindrical, tarsal claw terminal. Lengths of solenidia ω 1 6 (6–7)> ω 2 5 (5–6) = φ 1 5 (5–7) = φ 2 5 (5–6); ω 2 and φ 2 baculiform, φ 1 clavate, ω 1 finger-shaped. Setae dFe spatulate distally. Setae k blunt-ended. Seate l’, l” of genu, l’ of femur and v’ of trochanter blunt-ended. Leg II ( Fig. 10 B). Tarsus with padded claws bifurcate at tips and well-developed empodium. Solenidion ω 5 (5–6) finger-shaped, solenidion φ 3 (3) weakly clavate. Setae v’ of trochanter, u’ of tarsus and d of femur blunt-ended. Leg III ( Fig. 11 A). Claws of same shape as on tarsus II. Solenidion φ 3 (3) weakly clavate. Setae u’ of tarsus and all setae of femur blunt-ended. Femur divided into basi- and telofemur. Leg IV ( Fig. 11 B). Tarsal claws simple, empodium small. Solenidion φ 3 (3), weakly clavate. Setae v’ of trochanter, d of femur, d and v” of tibia blunt-ended. Femur divided into basi- and telofemur.

MALE and LARVA unknown.

Type material. Female holotype, slide AK 170514, RUSSIA, Tyumen Province, vicinity of Tyumen, in rotten log of birch ( Betula pendula ), 57o09’50.5” N, 65o27’24.2” E, 17 May 2014, coll. A.A. Khaustov; paratypes: 7 phoretic females, same data.

Etymology. The name of the new species is referring to habitat of a new species in the rotten wood.

Differential diagnosis. Phoretic females of a new species are most similar to P. mesembrinae ( Canestrini, 1881) based on redescription of P. mesembrinae by Camerik et al. (2006) by the absence of apodemes 5, three pairs of setae on coxal fields I and II, one-chambered stigmata, subequal and smooth setae e and h 1, subequal setae 2 a and 2 b, setae c 2 distinctly longer than c 1. It differs from P. mesembrinae by the position of setae e distinctly anterior to bases of setae f (vs. situated slightly posterior to bases of setae f in P. mesembrinae ) and by the position of setae c 1 distinctly anterior to setae c 2 (vs. situated distinctly posterior to c 2).

Figures

FIGURE 8. Pediculaster lignarius Khaustov sp. nov., phoretic female, idiosoma: A—dorsum, B—venter.

FIGURE 9. Pediculaster lignarius Khaustov sp. nov., phoretic female: pharyngeal pumps.

FIGURE 10. Pediculaster lignarius Khaustov sp. nov., phoretic female: A—leg I, B—leg II.

FIGURE 11. Pediculaster lignarius Khaustov sp. nov., phoretic female: A—leg III, B—leg IV.