Scutacarus spinisetus, 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 : 529-532

Scutacarus spinisetus sp. nov.

( Figs 23–26 )

Description. FEMALE ( Figs 23–26 ). Length of idiosoma 175 (175), width 155 (150).

Gnathosoma . Width of gnathosoma 17 (19). Gnathosoma completely covered by tergite C. Dorsal median apodeme indistinct. All gnathosomal setae smooth. Postpalpal setae needle-like, weakly blunt-ended, situated anterolaterally to setae cha. 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 23A , 26A ). Free margins of tergite C striated (not illustrated on Fig. 23A ). All dorsal shields with numerous round dimples ( Fig. 26A ). Prodorsum completely covered by tergite C. Lateral propodosomal spine present. Stigmata elongate, located dorsally. Anterior corners of prodorsum with short hornlike projections. Posterior parts of tergites C, D and EF with row of u-shaped elevations. Trichobothria with long stem, clavate, sparsely barbed, with rounded apex. Setae e, f, h 1, and h 2 with few weak barbs, other dorsal setae smooth. Setae e and h 2 pointed, other dorsal setae weakly blunt-ended. Setae d, e, f, h 1, and h 2 distinctly thickened in basal half, spiniform. Cupules ia on tergite D and ih on tergite H small, round. Posterior margin of tergite H with weak tongue-like projection. Lengths of dorsal setae: v 2 6 (7), sc 2 7 (6), c 1 14 (14), c 2 10 (10), d 10 (10), e 17 (19), f 14 (14), h 1 19 (18), h 2 16 (17). Distances between setae: v 2 –v 2 34 (40), sc 2 –sc 2 30 (37), c 1 – c 1 44 (47), c 1 – c 2 41 (42), d–d 120 (120), e–f 31 (33), f–f 71 (70), h 1 – h 1 23 (25), h 1 – h 2 35 (34).

Idiosomal venter ( Figs 23B , 26B ). Ventral plates with dimples as on dorsal shields ( Fig. 26B ). Setae 2 b bluntended and thickened, other ventral setae pointed. Setae 2 a, 2 b, 3 b, 4 a, ps 1, and ps 3 smooth, setae 3 a and ps 2 with one small barb each, other ventral setae distinctly barbed. Posterior margin of aggenital plate with deep 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 (24), 1 b 19 (19), 2 a 15 (14), 2 b 20 (21), 3 a 14 (16), 3 b 20 (21), 3 c 27 (28), 4 a 18 (17), 4 b 51 (53), 4 c 34 (36), ps 1 12 (11), ps 2 10 (9), ps 3 5 (5).

Legs ( Figs 24 , 25 ). Leg I ( Fig. 24A ). 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 (12), ω 2 11 (11), φ 1 8 (7), φ 2 8 (8); φ 1 clavate, ω 1 finger-shaped, ω 2 and φ 2 uniformly thin. Setae d, l’, v” of femur and l’ of genu weakly blunt-ended; setae l” and v’ of genu distinctly blunt-ended; other leg setae (except eupathidia) pointed. Setae l’ and v” of femur smooth; other leg setae (except eupathidia) barbed. Leg II ( Fig. 24B ). 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 12 (12) fingershaped, solenidion φ 5 (5) weakly clavate. Seta pl” spine-like, weakly barbed; setae d, l’ and v” of femur weakly blunt-ended, other leg setae pointed. Setae l’, v” of femur and u’, tc” of tarsus smooth, other leg setae barbed. Leg III ( Fig.25A ). Leg setation: Tr 1, Fe 2, Ge 2, Ti 4(1), Ta 6. Claws and empodium as on tarsus II. Solenidion φ 4 (3) weakly clavate. Seta pl” spine-like, smooth; seta d of femur weakly blunt-ended, other leg setae pointed. Setae v’ of trochanter, u’ and tc” of tarsus smooth, other leg setae barbed. Leg IV ( Fig. 25B ). 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 short 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 soil and debris under Dracophyllum muscoides cushion plant, 17 February 2014 (M. Minor), paratype: 1 female, 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 is deposited in the New Zealand National Arthropod Collection, Auckland, New Zealand ; 1 paratype is 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 radiculatus Mahunka, 1969 , described from Bolivia ( Mahunka 1969), by the absence of the claw on tibiotarsus I and the short, thick dorsal hysterosomal setae. It can be distinguished from the latter by setae 4 b more than two times longer than 4 a (vs. subequal in S. radiculatus ), by smooth setae ps 1 (vs. distinctly barbed in S. radiculatus ), and by setae ps 3 distinctly separated from ps 2 (vs. ps 3 situated close to ps 2 in S. radiculatus ).

Etymology. The name of the new species is a combination of two Latin words: spina meaning spine and seta meaning bristle and refers to the presence of short spiniform setae on the hysterosomal dorsum.

Figures

FIGURE 23. Scutacarus spinisetus sp. nov., female: A—dorsum of the body, B—venter of the body. Legs omitted.

FIGURE 24. Scutacarus spinisetus sp. nov., female: A—left leg I in dorsal view, B—left leg II in dorsal view.

FIGURE 25. Scutacarus spinisetus sp. nov., female: A—right leg III in dorsal view, B—left leg IV in ventral view.

FIGURE 26. DIC micrographs of Scutacarus spinisetus sp. nov., female: A—posterior half of the body in dorsal view, Banterior half of the body in ventral view.