Lutrilichus Fain, 1970

Bochkov, Andre V., 2018, External morphology of postembrionic stages of Lutrilichus javanicus (Acariformes: Chirodiscidae) from Melogale moschata (Carnivora: Mustelidae) from Vietnam, Acarologia 58 (4), pp. 763-772 : 764-771

Genus Lutrilichus Fain, 1970

Lutrilichus javanicus Fain, 1970 ( Figures 1-7 )

Lutrilichus javanicus Fain, 1970: 300, 1981: 43 , figs. 3, 4; Fain et al. 1974: 944.

Material examined — 10 males, 10 females, 10 male larvae, 10 female larvae, 5 male protonymphs, 10 female protonymphs, 10 male tritonymphs, 10 female tritonymphs, and numerous specimens retained in ethanol ( ZISP, AVB 17-1103-001) from the Chinese ferret badger Melogale moschata (Gray) ( Carnivora : Mustelidae ) ( ZISP, AVA 13-169), VIETNAM: Son La Province, Phu Yen District, Suoi To Commune, Suoi Khang Village, ca. 10 km NW of Phu Yen, 21°20′13.2′′N, 104°36′29.7′′E, alt 1100 m, 31 May 2013, coll. A. V. Abramov. Mites are deposited in the Museum of Zoology, the University of Michigan, Ann Arbor, USA ( UMMZ), and Zoological Institute of the Russian Academy of Sciences, Saint-Petersburg, Russia ( ZISP).

Male larva — (10 specimens, Figure 1 ) — Body 270–380 long and 165–255 wide. Gnathosoma . Gnathosoma having structure typical for Chirodiscidae with full complement of setae. Palps two-segmented, enclosed by membrane. Pseudorutellar membranes of subcapitulum weakly developed, dorsal lobes not developed. Palpal setae: dTi, dTil”, dTa, ω, ul’, and ul”; subcapitular setae: elcp and subc. Idiosoma . Idiosoma slightly flattened from lateral sides, completely covered by transverse striae. Propodonotal shield very short about 10 long, in shape of narrow transverse band. Hysteronotal shield absent. Hysteronotal gland openings gl distinct. Posterior margin of opisthosomal widely rounded. Laterocoxal setae scx absent. Anal opening situated ventrally. Lengths of setae: si 50–88, se 60–80, c1 55–63, c2 48–58, cp 45–50, c3 40–65, d1 33–45, d2 40–60, e1 50 –65, e2 58 –78, h2 150–210, 1a and 3a 15–20. Each pair of coxal apodemes Ia and IIa, fused in Y-shaped structures. Coxal apodemes IIIa fused medially in arch-like structure. Legs. Legs I and II with 5 segments: trochanter without setae, femur with seta vF, genu with setae cG and mG, tibia with seta gT and solenidion φ, tarsus with paired tarsal flaps and solenidion ω1. Legs III well developed, with full set of articulated segments: trochanter, femur, genu, tibia and tarsus with pretarsus. Ambulacral disc of pretarsus III with acute terminal protrusion. Leg III setation: genu: solenidion σ, tibia: seta kT and solenidion φ, tarsus: setae w, r, s, f, e, d. Setae s III and w III shaped as longitudinally striated spurs.

Male protonymph — (5 specimens, Figure 2A, B ) — Body 310–390 long and 210–265 wide. Idiosoma . Propodonotal shield about 10 long. One pair of genital papillae, setae f2, h3, ps1, ps2, ps3, and g added on idiosoma . Setae f2 situated closer to bases of h2 than ps2. Lengths of setae: si 70–90, se 80–100, c1, c2, cp, c3, d1, d2, e1, and e2 70–100; f2, ps1, ps2, and ps3 10–20; h2 100–120; h3 80–100. Coxal apodemes IVa fused medially into arch-like structure. Legs. Legs IV with five articulated segments added. Pretarsus IV present. Setae d, w, and r of tarsus IV present, other segments of legs IV without setae. Seta w IV shaped as longitudinally striated spur.

Male tritonymph — (10 specimens, Figure 2 C–F) — Body 410–450 long and 250–300 wide. Idiosoma . Propodonotal shield 10–15 long. Second pair of genital papillae, coxal setae 4a and 4b added on idiosoma . Lengths of setae: si 78–90, se 80–100, c1 50–70, c2 70–90, cp 45–70, c3 60–65, d1 45–50, d2 70–90, e1 and e2 60 –70, f2 18–25, h2 140–180, h3 80–100, ps1 5–10, ps2 23–28, ps3 38–53. Legs. Seta sR III on trochanter III, seta kT III on tibia III, and setae e IV and f IV on tarsus IV added.

Male — (10 specimens, Figures 5A and 6 ) — Body 365–425 long, 205–265 wide. Idiosoma . Propodonotal shield 10–18 long. Idiosomal dorsum covered with numerous transverse striae. Hysteronotal shield shaped of transverse band, situated posterior to setae e 1, 25 –35 in length along midline. Setae ps3 situated between adanal suckers. Opisthosomal lobes widely rounded. Lengths of idiosomal setae: si 80–100, se 100–115, c1 78–93, c2 93–105, cp 70–120, c3 40–65, d1 40–60, d2 80–95, e1 – microsetae, e2 70–100, f2 80–85, h2 130–180, h3 130–170, ps1 110–120, and ps2 100–125. Aedeagus about 11 long. Adanal sclerites absent. Legs III 110–140 long, with setation as in male tritonymph. Legs IV 70–90 long, consisting of 4 segments, femur and genu fused. Solenidion σ III added on genu III. Tarsi IV bearing setae d, w, and r, tibia IV with solenidion φ IV, other segments of legs IV without setae. Seta w IV shaped as longitudinally striated spur.

Female larva — (10 specimens, Figure 3 ) — Similar to male larva. Body 250–300 long and 160–205 wide. Idiosomal dorsum posterior to level of setal bases c2 and d1 smooth. Lengths of idiosomal setae: si 88–120, se 75–125, c1 28–38, c2 80–100, cp 80–120, c3 70–85, d1 2–3, d2 25–30, e1 110–125, e2 60 –90, h2 180–240, 1a 10–20, and 3a 30–40. Setae e1 thickened and situated terminally. Live independently or attached to male.

Female protonymph — (10 specimens, Figure 4A, B ) — Body 255–265 long and 190–210 wide, slightly elongated sack-like. Coxal fields I smooth; coxal apodemes II–IV absent. Setae c3, e1, e2, d1, d2, f2, 3a, g, ps1, ps2, and ps3 absent. Setae h3 added. Lengths of setae: si 88–93, se 100–110, c1 10–15, c2 5–8, cp 30–35, 1a about 10, h2 and h3 28–35. Posterior end of opisthosoma between levels of setae e1 and h2 smooth, anterior margin of this area flanked with a pair of large bow-shaped opisthosomal sclerites and bears pair of rounded tubercles corresponding to male adanal suckers. Legs I strongly shortened compared to female larva, their tibia and tarsus clearly separated. Setation of legs I as in female larva, but all setae shorter. Legs II–IV absent. First pair of genital papillae added.

Female tritonymph — (10 specimens, Figure 4C ) — Similar to female protonymph. Body 335–350 long and 245–305 wide. Idiosoma . Propodonotal shield 10–15 long. Second pair of genital papillae added. Idiosomal chaetome as in female protonymph. Lengths of idiosomal setae: si 80–135, se 125–155, c1 and c2 5–8, cp 25–50, h2 and h3 20–35, 1a about 10. Legs. Legs I as in female protonymph. Legs II strongly reduced, several times shorter and thinner than legs I, consisting of 3 articulated segments, apical segment with 3 short setae. Legs III and IV primordial, shaped as small conical tubercles not split into segments, each bearing 1 apical microseta.

Female — (10 specimens, Figures 5B and 7 ) — Similar to male tritonymph except oviporus between coxal fields III. Body 440–490 long, 275–330 wide. Idiosoma . Propodonotal shield about 10 long. Full set of idiosomal setae occurring in adult chirodiscids excluding setae h1 (as in male). Coxal apodemes I–III as in male tritonymph. Lengths of setae: si 100–125, se 100–120, c1 75–85, c2 80–105, cp 83–105, c3 75–85, d1 58–80, d2 85–95, e1 95–130, e2 95–125, f2 19–25, h2 135–170, h3 140–160, ps1 10–23, ps2 25–38, and ps3 50–70. Legs. Legs I and II as in male. Legs III and IV fully developed as in male tritonymph; setation of legs III and tibia IV as in male, tarsus IV with 5 setae d, e, f, r, and w. Seta w IV shaped as longitudinally striated spur. Ovoviviparous.

Figures

Figure 1 Lutrilichus javanicus Fain, 1970, male larva. A – Lateral view; B – Leg III in ventral view. Scale bars: A = 100 μm; B = 50 μm.

Figure 2 Lutrilichus javanicus Fain, 1970,male nymphs. (A, B) protonymph: A – Lateral view; B – Leg IV in ventral view. (C–F) deutonymph: C – Lateral view; D – Coxal fields III, E – Tarsus and tibia IV in dorsal view; F – Tarsus IV in ventral view. Scale bars: A, C = 100 μm; B, D – F = 50 μm.

Figure 3 Lutrilichus javanicus Fain, 1970, female larva. A – Dorsal view; B – Ventral view; C – Leg III in ventral view. Scale bars: A, B = 100 μm; C = 50 μm.

Figure 4 Lutrilichus javanicus Fain, 1970, female nymphs. (A, B) protonymph: A – Lateral view; B – Leg I in ventral view. C – Tritonymph in lateral view. Scale bars: A, C = 100 μm; B = 50 μm.

Figure 5 Lutrilichus javanicus Fain, 1970, adults in lateral view. A – Male; B – Female.

Figure 6 Lutrilichus javanicus Fain, 1970, details of male. A – Palp in ventral view; B – Cheliceral digits in lateral view; C – Coxal fields III; D – Opisthosomal lobes in dorsal view; E – Opisthosomal lobes in ventral view; F – Tarsus, tibia, and genu III in ventral view; G – Leg IV in ventral view.

Figure 7 Lutrilichus javanicus Fain, 1970, details of female. A – Coxal fields III; B – E Legs I–IV in ventral view, respectively.