Scutacarus isotrichus, 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 : 518-523

Scutacarus isotrichus sp. nov.

( Figs 12–16 )

Description. FEMALE ( Figs 12–16 ). Length of idiosoma 160 (150–160), width 115 (100–115).

Gnathosoma . Length of gnathosoma 20 (19–20), width 16 (15–16). Gnathosoma usually not covered by tergite C. Dorsal median apodeme well developed. All gnathosomal setae smooth and pointed. Setae cha 10 (9–10), chb 11 (10–11). Postpalpal setae not evident. Setae dFe shorter than dGe. Pits n present in posterior part of subcapitulum. 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 pump 2 smooth, subequal with pharyngeal pump 1; pharyngeal pump 3 distinctly longer than pumps 1 and 2, bent dorsally.

Idiosomal dorsum ( Figs 12A , 15A , 16A, B ). Free margins of tergite C striated (not illustrated on Fig. 12A ). All dorsal shields with numerous round dimples ( Figs 16A, B ). Prodorsum only partly covered by tergite C. Lateral propodosomal spine absent. Stigmata elongate, located dorsally. Anterior corners of prodorsum with horn-like projections. Posterior margins of tergites C, D and EF weakly undulate. Setae c 2 with short alveolar canal. Setae v 2 and sc 2 smooth, other dorsal setae barbed. Setae e, and h 2 pointed, other dorsal setae blunt-ended. Trichobothria with long stem, clavate, sparsely barbed, with rounded apex. Cupules ia on tergite D and ih on tergite H small, round. Posterior margin of tergite H with short tongue-like projection. Tergite C with paired porous areas located posteriorly to setae c 1; tergite H with a pair of oval porous areas located anteriorly to setae h 1. Lengths of dorsal setae: v 2 8 (7–8), sc 2 9 (7–9), c 1 22 (20–23), c 2 21 (20–21), d 27 (25–28), e 24 (23–25), f 29 (27–30), h 1 29 (27–30), h 2 16 (15–18). Distances between setae: v 2 –v 2 35 (31–36), sc 2 –sc 2 31 (28–31), c 1 – c 1 37 (36–38), c 1 – c 2 27 (24–27), d–d 86 (81–86), e–f 27 (20–27), f–f 49 (49–55), h 1 – h 1 33 (32–33), h 1 – h 2 28 (23–28).

Idiosomal venter ( Figs 12B , 15B , 16C, D ). Ventral plates with dimples as on dorsal shields ( Figs 16C, D ). Setae 2 b, ps 1, and ps 2 blunt-ended, setae ps 3 weakly blunt-ended, other ventral setae pointed. Setae 2 b, 3 b, 4 a, and ps 3 smooth, other ventral setae barbed. Posterior margin of aggenital plate weakly concave. Secondary transverse apodeme absent. Ap1, ap2 and apsej well developed and joined with appr; ap2 forming u-like structure; ap3 very thin, straight, ap4 short; ap5 absent. Ags bell-like; pgs triangular. Distance between setae 4 a –4 b more than two times shorter than 4 a –4 a. Lengths of ventral setae: 1 a 19 (19–21), 1 b 16 (16–18), 2 a 15 (15–17), 2 b 15 (15–16), 3 a 17 (16–17), 3 b 26 (26–29), 3 c 19 (17–19), 4 a 28 (26–28), 4 b 41 (39–46), 4 c 30 (30–33), ps 1 10 (10–11), ps 2 9 (8– 9), ps 3 4 (3–4).

Legs ( Figs 13 , 14 ). Leg I ( Fig. 13A ). 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 10 (10), ω 2 7 (7), φ 1 7 (7–8), φ 2 6 (6); φ 1 clavate, ω 1 finger-shaped, ω 2 and φ 2 uniformly thin. Setae d, l’, v” of femur, (l), v’ of genu bluntended; other leg setae (except eupathidia) pointed. Setae l’, v” of femur, d and s of tibiotarsus smooth; other leg setae (except eupathidia) barbed. Leg II ( Fig. 13B ). 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 8 (8–9) finger-shaped, solenidion φ 5 (5) weakly clavate. Seta pl” spine-like, smooth; setae d, l’ and v” of femur blunt-ended, other leg setae pointed. Setae v” of femur, u’ and tc” of tarsus smooth, other leg setae barbed. Leg III ( Fig.14A ). Leg setation: Tr 1, Fe 2, Ge 2, Ti 4(1), Ta 6. Claws and empodium as on tarsus II. Solenidion φ 4 (4) weakly clavate. Seta pl” spine-like, smooth; seta d of femur blunt-ended, other leg setae pointed. Setae u’ and tc” of tarsus smooth, other leg setae barbed. Leg IV ( Fig. 14B ). Leg setation: Tr 1, Fe 2, Ge 1, TiTa 7. Tibiotarsus short, about as long as wide. All leg setae barbed. Seta d of femur weakly blunt-ended, other leg setae pointed.

MALE and LARVA unknown.

Type material. Female holotype: New Zealand, Central Otago, Old Man’s Range, 45° 18' 58.45"S, 169° 11' 45.21"E, 1646 m a.s.l., in bare soil between cushion plants, 17 February 2014 (M. Minor). Paratypes: 1 female, New Zealand, Central Otago, Old Man’s Range, 45° 18' 58.45"S, 169° 11' 45.21"E, 1646 m a.s.l., in bare soil between cushion plants, 17 February 2014 (M. Minor); 2 females, New Zealand, Central Otago, Pisa Range, 44° 52' 11.1"S, 169° 10' 9.20"E, 1797 m a.s.l., in bare soil between cushion plants, 18 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 coronatus Mahunka, 1981 , described from Hungary ( Mahunka 1981) by the absence of claw on tibiotarsus I, blunt-ended setae ps 1, 2 and c 2, and similar lengths of dorsal idiosomal setae. It can be distinguished from the latter by subequal setae 2 a and 2 b (vs. 2 b distinctly shorter than 2 a in S. coronatus ), by setae e distinctly longer than h 2 (vs. subequal in S. coronatus ), by setae ps 3 distinctly shorter than ps 1, 2 (vs. subequal n S. coronatus ), and by the distance between setae 4 a –4 b more than two times shorter than 4 a –4 a (vs. 4 a –4 b subequal to 4 a –4 a in S. coronatus ).

Etymology. The name of the new species is a combination of two Greek words: ίσoς meaning equal, and τρίχες meaning seta, and refers to equal lengths of most dorsal idiosomal setae.

Figures

FIGURE 12. Scutacarus isotrichus sp. nov., female: A—dorsum of the body, B—venter of the body. Legs omitted.

FIGURE 13. Scutacarus isotrichus sp. nov., female: A—right leg I in dorsal view, B—right leg II in dorsal view.

FIGURE 14. Scutacarus isotrichus sp. nov., female: A—right leg III in dorsal view, B—right leg IV in dorsal view.

FIGURE 15. DIC micrographs of Scutacarus isotrichus sp. nov., female: A—dorsal view, B—ventral view.

FIGURE 16. DIC micrographs of Scutacarus isotrichus 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.