Scutacarus incisus, 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 : 525-529

Scutacarus incisus sp. nov.

( Figs 17–22 )

Description. F EMALE ( Figs 17–22 ). Length of idiosoma 190 (190–195), width 180 (175–185).

Gnathosoma ( Fig. 18 ). Length of gnathosoma 21 (20–21), width 19 (18–20). Gnathosoma completely covered by tergite C. Dorsal median apodeme reduced. All gnathosomal setae smooth. Postpalpal setae needle-like, weakly blunt-ended, situated anterolaterally to setae cha. Other gnathosomal setae pointed. Setae cha 9 (9–10), chb 11 (10– 11). Setae dFe slightly shorter than dGe. Pits n not evident. Ass well-developed, palpal solenidion not evident. Setae m 10 (9–10). Pharyngeal pumps separated. Pharyngeal pump 1 oval, striated, situated inside gnathosomal capsule; pharyngeal pumps 2 and 3 indiscernible.

Idiosomal dorsum ( Figs 17A , 21A , 22A, B ). Free margins of tergite C striated (not illustrated on Fig. 17A ). All dorsal shields with numerous large round dimples ( Figs 22A, B ). Prodorsum completely covered by tergite C. Lateral propodosomal spine present. Stigmata elongate, located dorsally. Posterior margins of tergites C, D and EF weakly undulate. Setae e and h 2 barbed, pointed and slightly thickened, other dorsal setae smooth and weakly blunt-ended. Trichobothria with long stem, clavate, sparsely barbed, with rounded apex. Posterolateral margins of tergite C with deep incisions. Cupules ia on tergite D and ih on tergite H small, round. Posterior margin of tergite H evenly rounded. Lengths of dorsal setae: v 2 7 (7–8), sc 2 6 (6–7), c 1 9 (9–10), c 2 7 (7–8), d 7 (7–8), e 13 (13–15), f 9 (8–9), h 1 10 (9–10), h 2 13 (13–15). Distances between setae: v 2 –v 2 39 (37–40), sc 2 –sc 2 35 (32–35), c 1 – c 1 47 (46–49), c 1 – c 2 44 (44–52), d–d 120 (115–120), e–f 16 (15–16), f–f 100 (100–105), h 1 – h 1 47 (47–52), h 1 – h 2 20 (20–22).

Idiosomal venter ( Figs 17B , 21B , 22C, D ). Ventral plates with large dimples as on dorsal shields ( Figs 22C, D ). Setae 2 b blunt-ended, thickened and flattened, other ventral setae pointed. Setae 2 b, 3 a, 3 b, 4 a, 4 b, and ps 3 smooth, other ventral setae barbed. Posterior margin of aggenital plate rounded. Secondary transverse apodeme absent. Ap1, ap2 and apsej well developed and joined with appr; ap2 forming w-like structure; ap3 indistinct, ap4 short; ap5 absent. Ags bell-like; pgs triangular. Well sclerotized chitinous curved ridges present posterolaterally to legs IV. Lengths of ventral setae: 1 a 18 (18–20), 1 b 18 (18–20), 2 a 15 (14–18), 2 b 19 (18–19), 3 a 10 (10–12), 3 b 12 (11–12), 3 c 32 (32–42), 4 a 10 (10–12), 4 b 13 (12–14), 4 c 41 (38–42), ps 1 12 (12–13), ps 2 7 (7–8), ps 3 7 (7–8).

Legs ( Figs 19 , 20 ). Leg I ( Fig. 19A ). Leg setation: Tr 1, Fe 1, Ge 4, TiTa 16(4). Tibiotarsus without pretarsus and claw. Tibiotarsus cylindrical, with pinnaculum bearing seta tc”. Lengths of solenidia ω 1 11 (11–12), ω 2 8 (9– 11), φ 1 9 (8–9), φ 2 7 (7–9); φ 1 clavate, ω 1 finger-shaped, ω 2 and φ 2 uniformly thin. Setae d of femur and v’ of genu weakly blunt-ended; seta l” of genu distinctly blunt-ended; other leg setae (except eupathidia) pointed. Setae pl’, (pv) and s of tibiotarsus smooth; other leg setae (except eupathidia) barbed. Setae l’ and v” of femur absent. Leg II ( Fig. 19B ). Leg setation: Tr 1, Fe 1, 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 4 (4) weakly clavate. Seta pl” spine-like, smooth, with subapical seta-like projection; seta l’ of tibia thick, comb-like, seta d of femur weakly blunt-ended, other leg setae pointed. Setae u’ and tc” of tarsus smooth, other leg setae barbed. Setae l’ and v” of femur absent. Leg III ( Fig.20A ). Leg setation: Tr 1, Fe 1, Ge 2, Ti 4(1), Ta 6. Claws and empodium as on tarsus II. Solenidion φ 4 (4) weakly clavate. Seta pl” spine-like, with several barbs and subapical seta-like projection; 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. 20B ). Leg setation: Tr 1, Fe 2, Ge 1, TiTa 7. Tibiotarsus short, slightly longer than its width. All leg setae pointed. Seta tc’ of tarsus smooth, thickened, other leg setae barbed. Trochanter dorsally with short spine-like projection.

MALE and LARVA unknown.

Type material. Female holotype: New Zealand, Central Otago, Old Man’s Range , 45° 19' 7.60" S, 169° 12' 11.49" E, 1655 m a.s.l., in soil and debris under Raoulia sp. cushion plant, 17 February 2014 (M. Minor). Paratypes : 10 females, New Zealand, Central Otago, Old Man’s Range , 45° 19' 7.60" S, 169° 12' 11.49" E, 1655 m a.s.l., in soil and debris under Raoulia sp. cushion plant, 17 February 2014 (M. Minor) ; 1 female, New Zealand, Central Otago, Old Man’s Range , 45° 19' 7.60" S, 169° 12' 11.49" E, 1655 m a.s.l., in bare soil between cushion plants, 17 February 2014 (M. Minor) ; 5 females, New Zealand, Central Otago, Old Man’s Range , 45° 18' 59.85"S, 169° 11' 45.19"E, 1639 m a.s.l., alpine herbaceous snowbank, in soil, 17 February 2014 (M. Minor) ; 2 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 3 paratypes are deposited in the New Zealand National Arthropod Collection, Auckland, New Zealand ; 15 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 cactaeformis Mahunka, 1967 , described from Australia ( Mahunka 1967), by the absence of the claw on tibiotarsus I, slightly thickened setae e and h 2, short and smooth setae 3 a, 3 b, 4 a, 4 b, long and strongly barbed 3 c and 4 c, and thick and smooth seta tc’ on tibiotarsus IV. It can be distinguished from the latter by the much shorter dorsal setae c 1, c 2, d, f, and h 1, which are shorter than e and h 2 (vs. c 1, c 2, d, f, and h 1 distinctly longer than e and h 2 in S. cactaeformis ), and by smooth setae c 1 and c 2 (vs. barbed in S. cactaeformis ).

Etymology. The name of the new species is derived from the Latin incisus meaning having been cut, and refers to the presence of deep incisions on posterolateral margins of tergite C.

Figures

FIGURE 17. Scutacarus incisus sp. nov., female: A—dorsum of the body, B—venter of the body. Legs omitted.

FIGURE 18. Scutacarus incisus sp. nov., female: A—gnathosoma in dorsal view, B—gnathosoma in ventral view.

FIGURE 19. Scutacarus incisus sp. nov., female: A—left leg I in dorsal view, B—right leg II in dorsal view.

FIGURE 20 Scutacarus incisus sp. nov., female: A—right leg III in dorsal view, B—right leg IV in ventral view.

FIGURE 21. DIC micrographs of Scutacarus incisus sp. nov., female: A—dorsal view, B—ventral view.

FIGURE 22. DIC micrographs of Scutacarus incisus 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.