Scutacarus cornutus, 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 : 532-537

Scutacarus cornutus sp. nov.

( Figs 27–31 )

Description. FEMALE ( Figs 27–31 ). Length of idiosoma 170 (170–180), width 135 (135–145).

Gnathosoma . Length of gnathosoma 20 (20–21), width 18 (16–18). Gnathosoma usually not covered by tergite C. Dorsal median apodeme well developed. All gnathosomal setae smooth. Postpalpal setae needle-like, weakly blunt-ended, situated anterolaterally to setae cha. Other gnathosomal setae pointed. Setae cha 9 (8–9), chb 11 (10– 11). Setae dFe and dGe subequal. Pits n present in posterior part of subcapitulum. Ass well-developed, palpal solenidion not evident. Setae m 10 (9–10). Pharyngeal pumps separated and striated. Pharyngeal pump 1 oval, situated inside gnathosomal capsule; pharyngeal pump 2 large, elongate-oval, more than two times longer than pump 1; pharyngeal pump 3 subequal to pump 2, bent dorsally.

Idiosomal dorsum ( Figs 27A , 30A , 31A, B ). Free margins of tergite C striated (not illustrated on Fig. 27A ). All dorsal shields with numerous small round dimples ( Figs 31A, B ). Prodorsum only partly covered by tergite C. Lateral propodosomal spine present. Stigmata elongate, located dorsally. Anterior corners of prodorsum with hornlike projections. Posterior parts of tergites C, D and EF with row of u-shaped elevations. Setae c 2 with short alveolar canal. Setae v 2 and sc 2 smooth, other dorsal setae barbed. Setae c 1, c 2, e, and h 2 pointed, other dorsal setae weakly 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 and associated with pore-like structures; tergite EF with a pair of oval porous areas located anteriorly to setae f. Lengths of dorsal setae: v 2 7 (6–7), sc 2 8 (7–8), c 1 31 (30–31), c 2 29 (26–29), d 27 (26–28), e 33 (29–33), f 38 (38–42), h 1 29 (29–34), h 2 24 (23–28). Distances between setae: v 2 – v 2 39 (37–39), sc 2 –sc 2 34 (32–35), c 1 – c 1 45 (45–48), c 1 – c 2 32 (29–33), d–d 100 (100–105), e–f 27 (27–29), f–f 66 (66–68), h 1 – h 1 28 (28–33), h 1 – h 2 31 (29–32).

Idiosomal venter ( Figs 27B , 30B , 31C, D ). Ventral plates with dimples as on dorsal shields ( Figs 31C,D ). Setae 2 b, ps 1, and ps 2 blunt-ended, other ventral setae pointed. Setae 2 b, 3 b, 4 a, and ps 3 smooth; setae 2 a, 3 a, ps 1, and ps 2 with few minute barbs, other ventral setae distinctly barbed. Posterior margin of aggenital plate weakly concave. Secondary transverse apodeme absent. Ap1, ap2 and apsej well developed and joined with appr; ap3 very thin, straight, ap4 short; ap5 absent. Ags bell-like; pgs triangular. Distance between setae 4 a -4 b two times shorter than 4 a -4 a. Posterior part of posterior sternal plate with u-shaped elevations. Lengths of ventral setae: 1 a 22 (18–22), 1 b 23 (20–23), 2 a 18 (17–18), 2 b 15 (15–16), 3 a 16 (16–17), 3 b 21 (21–22), 3 c 21 (21–22), 4 a 16 (15–17), 4 b 39 (39– 47), 4 c 31 (30–33), ps 1 11 (10–11), ps 2 10 (9–10), ps 3 9 (8–9).

Legs ( Figs 28 , 29 ). Leg I ( Fig. 28A ). 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 9 (8–9), φ 1 7 (6–7), φ 2 8 (7–8); φ 1 clavate, ω 1 finger-shaped, ω 2 and φ 2 uniformly thin. Setae d, l’, v” of femur, (l) of genu bluntended; other leg setae (except eupathidia) pointed. Setae l’, v” of femur smooth; other leg setae (except eupathidia) barbed. Leg II ( Fig. 28B ). 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 9 (9) finger-shaped, solenidion φ 5 (5) weakly clavate. Seta pl” spinelike, with several barbs; setae d, l’ and v” of femur blunt-ended, other leg setae pointed. Setae v” of femur and u’ of tarsus smooth, other leg setae barbed. Leg III ( Fig.29A ). 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 bluntended, other leg setae pointed. Setae u’ and tc” of tarsus smooth, other leg setae barbed. Leg IV ( Fig. 29B ). 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. Trochanter dorsally with short spine-like projection.

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 soil and debris under Dracophyllum muscoides cushion plant, 17 February 2014 (M. Minor). Paratypes : 6 females New Zealand, Central Otago, Old Man’s Range , 45° 18' 58.45"S, 169° 11' 45.21"E, 1646 m a.s.l., in soil and debris under Dracophyllum muscoides cushion plant, 17 February 2014 (M. Minor) ; 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) ; 1 female, New Zealand, Central Otago, The Remarkables , 45° 3' 38.19"S, 168° 48' 49.51"E, 1839 m a.s.l., in soil and debris under Dracophyllum muscoides cushion plant, 19 February 2014 (M. Minor) .

Type deposition. The holotype and 2 paratypes are deposited in the New Zealand National Arthropod Collection, Auckland, New Zealand ; 6 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 quadrangularis ( Paoli, 1911) and S. uniformis Delfinado, Baker and Abbatiello, 1976 by the absence of the claw on tibiotarsus I, blunt-ended setae ps 1, 2 and pointed c 2. It can be distinguished from both species by setae f distinctly longer than d (vs. subequal in S. quadrangularis and S. uniformis ) and by setae 4 a not reaching posterior margin of posterior sternal plate (vs. 4 a reaching beyond posterior margin of posterior sternal plate in S. quadrangularis and S. uniformis ). From S. uniformis it also differs by the presence of well-developed horn-like projections near the stigmata (vs. absent n S. uniformis ).

Etymology. The name of the new species is derived from the Latin cornu meaning horn and refers to the hornlike projections on the prodorsum near the stigmata.

Figures

FIGURE 27. Scutacarus cornutus sp. nov., female: A—dorsum of the body, B—venter of the body. Legs omitted.

FIGURE 28. Scutacarus cornutus sp. nov., female: A—right leg I in dorsal view, B—right leg II in dorsal view.

FIGURE 29. Scutacarus cornutus sp. nov., female: A—right leg III in dorsal view, B—right leg IV in ventral view.

FIGURE 30. DIC micrographs of Scutacarus cornutus sp. nov., female: A—dorsal view, B—ventral view.

FIGURE 31. DIC micrographs of Scutacarus cornutus 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.