Scutacarus crassus, Khaustov & Minor, 2018

Khaustov, Alexander A. & Minor, Maria A., 2018, New species and a new record of the mite family Scutacaridae (Acari: Heterostigmata) from alpine New Zealand, Zootaxa 4508 (4), pp. 507-550 : 543-546

Scutacarus crassus sp. nov.

( Figs 38–42 )

Description. FEMALE ( Figs 38–42 ). Length of idiosoma 165 (165–180), width 150 (150–160).

Gnathosoma . Width of gnathosoma 18 (17–18). Gnathosoma completely covered by tergite C. Dorsal median apodeme well developed. All gnathosomal setae smooth and pointed. Postpalpal setae not evident. Other gnathosomal setae pointed. Setae cha 7 (8), chb 9 (10). Setae dFe slightly shorter than dGe. Ventral surface of gnathosoma not visible in available specimens. Pharyngeal pumps indistinct.

Idiosomal dorsum ( Figs 38A , 41A , 42A, B ). Free margins of tergite C striated (not illustrated on Fig. 38A ). All dorsal shields with numerous round dimples ( Figs 42A, B ). Prodorsum completely covered by tergite C. Lateral propodosomal spine present. Stigmata elongate, located dorsoventrally. Posterior parts of tergites C, D, EF and H with row of u-shaped elevations. Trichobothria with long stem, clavate, sparsely barbed, with rounded apex. Setae v 2 and sc 2 smooth, other dorsal setae weakly barbed. Setae sc 2 distinctly thicker than v 2. Setae c 2, e and h 2 pointed, other dorsal setae weakly blunt-ended. Setae e, f, h 1, and h 2 thickened in basal half. Cupules ia on tergite D and ih on tergite H small, round. Posterior margin of tergite H with weak tongue-like projection. Setae c 2 associated with short alveolar canal. Tergites EF and H each with a pair of oval porous areas located anteriorly to setae f and h 1, respectively. Lengths of dorsal setae: v 2 7 (7–8), sc 2 7 (7–8), c 1 18 (17–20), c 2 16 (16–19), d 17 (17–19), e 29 (28– 31), f 19 (19–21), h 1 21 (21–23), h 2 19 (19–25). Distances between setae: v 2 –v 2 41 (40–41), sc 2 –sc 2 35 (34–36), c 1 – c 1 44 (41–44), c 1 – c 2 42 (42–44), d–d 115 (115–125), e–f 29 (29–34), f–f 71 (71–76), h 1 – h 1 29 (29–33), h 1 – h 2 33 (32– 33).

Idiosomal venter ( Figs 38B , 41B , 42C, D ). Ventral plates with dimples as on dorsal shields ( Figs 42C, D ). Setae 2 b blunt-ended and thickened, other ventral setae pointed. Setae 4 a, ps 2, and ps 3 smooth, other ventral setae barbed. Posterior margin of aggenital plate with weak incision. Secondary transverse apodeme absent. Ap1, ap2 and apsej well developed and joined with appr; ap3 weak, linear, ap4 short; ap5 absent. Ags bell-like; pgs triangular. Posterior part of posterior sternal plate with row of u-shaped elevations. Lengths of ventral setae: 1 a 23 (23–25), 1 b 22 (22–26), 2 a 17 (16–19), 2 b 19 (18–20), 3 a 15 (15–17), 3 b 22 (22–25), 3 c 26 (26–28), 4 a 20 (20– 21), 4 b 64 (64–74), 4 c 40 (39–42), ps 1 14 (14–16), ps 2 9 (9–11), ps 3 7 (7–9).

Legs ( Figs 39 , 40 ). Leg I ( Fig. 39A ). Leg setation: Tr 1, Fe 3, Ge 4, TiTa 16(4). Tibiotarsus without pretarsus and claw. Tibiotarsus cylindrical, with pinnaculum bearing seta tc”. Lengths of solenidia ω 1 11 (11–13), ω 2 10 (10– 11), φ 1 7 (7–8), φ 2 8 (8–9); φ 1 weakly clavate, ω 1 finger-shaped, ω 2 and φ 2 uniformly thin. Setae d, l’, v” of femur, (l) and v’ of genu blunt-ended; other leg setae (except eupathidia) pointed. Setae l’ and v” of femur smooth; other leg setae (except eupathidia) barbed. Leg II ( Fig. 39B ). Leg setation: Tr 1, Fe 3, Ge 3, Ti 4(1), Ta 6(1). Tarsus with symmetrical hooked claws and flipper-like empodium. Solenidion ω 11 (11–12) finger-shaped, solenidion φ 3 (3– 4) weakly clavate. Seta pl” spine-like, smooth; setae d, l’ and v” of femur weakly blunt-ended, other leg setae pointed. Setae v” of femur and u’, tc” of tarsus smooth, other leg setae barbed. Leg III ( Fig.40A ). Leg setation: Tr 1, Fe 2, Ge 2, Ti 4(1), Ta 6. Claws and empodium as on tarsus II. Solenidion φ 3 (3–4) weakly clavate. Seta pl” spine-like, smooth; seta d of femur weakly blunt-ended, other leg setae pointed. Setae u’ and tc” of tarsus smooth, other leg setae barbed. Leg IV ( Fig. 40B ). Leg setation: Tr 1, Fe 2, Ge 1, TiTa 7. Tibiotarsus short, slightly longer than its width. All leg setae barbed. Seta d of femur blunt-ended, other leg setae pointed. Trochanter dorsally with strong spine-like projection.

MALE and LARVA unknown.

Type material. Female holotype: New Zealand, Central Otago, Old Man’s Range, 45° 20' 3.78"S, 169° 12' 25.26"E, 1649 m a.s.l., in bare soil between cushion plants, 17 February 2014 (M. Minor), paratypes: 3 females, New Zealand, Central Otago, Old Man’s Range, 45° 20' 3.78"S, 169° 12' 25.26"E, 1649 m a.s.l., in bare soil between cushion plants, 17 February 2014 (M. Minor).

Type deposition. The holotype and 1 paratype are deposited in the New Zealand National Arthropod Collection, Auckland, New Zealand ; 2 paratypes are deposited in the mite collection of the Tyumen State University Museum of Zoology , Tyumen, Russia .

Differential diagnosis. The new species is most similar to Scutacarus spinisetus sp. nov., by the absence of the claw on tibiotarsus I, and short and thickened dorsal setae. It can be distinguished from the latter by slender setae d (vs. distinctly thickened, spiniform in S. spinisetus ), by pointed setae c 2 (vs. blunt-ended in S. spinisetus ), by weakly barbed setae c 1, c 2, and d (vs. smooth in S. spinisetus ), by the absence of horn-like projections near stigmata (vs. present in S. spinisetus ), and by much longer setae 4 b (64–74) (vs. 51–53 in S. spinisetus ).

Etymology. The name of the new species is derived from Latin crassus meaning thick and refers to the thickened dorsal idiosomal setae.

Figures

FIGURE 38. Scutacarus crassus sp. nov., female: A—dorsum of the body, B—venter of the body. Legs omitted.

FIGURE 39. Scutacarus crassus sp. nov., female: A—right leg I in dorsal view, B—right leg II in dorsal view.

FIGURE 40. Scutacarus crassus sp. nov., female: A—right leg III in dorsal view, B—right leg IV in ventral view.

FIGURE 41. DIC micrographs of Scutacarus crassus sp. nov., female: A—dorsal view, B—ventral view.

FIGURE 42. DIC micrographs of Scutacarus crassus sp. nov., female: A—anterior half of the body in dorsal view, Bposterior half of the body in dorsal view, C—anterior half of the body in ventral view, D—posterior half of the body in ventral view.