Stigmaeus patagoniensis, Khaustov, 2016

Khaustov, A. A., 2016, New species and records of mites of the family Stigmaeidae (Acari: Prostigmata) collected from mosses in Southern Chile, Acarologia 56 (4), pp. 639-679 : 664-668

Stigmaeus patagoniensis n. sp.

( Figures 23-26 )

Description

Female ( Figures 23-26 ) — Length of idiosoma 455, width 300.

Idiosomal dorsum ( Figure 23A ) — Idiosoma oval, soft, mostly covered by smooth dorsal plates. Eyes present. Propodosomal plate with setae vi, ve and sci; setae sce situated on separate platelets. Postocular bodies large, weakly defined. Striae anteriorly to propodosomal plate without microtubercles. Setae c 1, d 1 and e 1 blunt-ended, other dorsal setae pointed. All dorsal setae smooth. Setae ve, sce, c 2, e 2 and f 1 very long and flexible. Ratio ve/sci = 7,8. Central hysterosomal plate with two pairs of setae. Suranal plate not divided, with two pairs of setae. Lengths of dorsal setae: vi 64, ve 150, sci 19, sce 135, c 1 43, c 2 135, d 1 35, d 2 125, e 1 34, e 2 135, f 1 140, h 1 56, h 2 61.

Idiosomal venter ( Figure 23B ) — Ventral setae smooth or weakly barbed, pointed. Three pairs of aggenital setae; ag 1 situated on small platelets; ag 2-3 on single platelet. One pair of genital setae. Endopodal plates without subcuticular reticulation. Lengths of ventral setae: 1 a 36, 1 b 35, 1 c 65, 2 b 52, 2 c 33, 3 a 31, 3 b 29, 3 c 23, 4 a 36, 4 b 23, 4 c 25, ag 1 27, ag 2 25, ag 3 36, g 17, ps 1 70, ps 2 35, ps 3 24.

Gnathosoma ( Figure 24 ) — Tibial claw large. Setae l’ of palpal tibia spine-like. All palpal setae pointed; setae of femur and genu weakly barbed; all setae of palptarsus smooth. Number of setae on palpal segments: Tr 0, Fe 3 (d, l’, v"), Ge 2 (d, l"), Ti 3 (d, l’, l"), Ta 8(1) (fused eupathidia ul’, ul", sul, eupathidion acm, ba, bp, lp, 1 solenidion ω). Palpal supracoxal setae (ep) with thickened basal part and thin distal one. Chelicerae dorsally smooth. Rostrum of subcapitulum long. Subcapitular setae pointed; n weakly barbed, other subcapitular setae smooth. Basal part of subcapitulum without reticulation. Lengths of subcapitular setae: m 48, n 26, or 1 25, or 2 28.

Legs ( Figures 25 , 26 ) — Empodial raylets weakly capitate. Leg segments without reticulation. Leg I ( Figure 25A ). Coxae I posterodorsally with supracoxal setae (el) thickened basally and thin in distal half. Leg setation: Tr 1 (v’), Fe 6 (d, l’, l", v’, v", bv"), Ge 4 (d, l’, l", k), Ti 5(2) (d, l’, l", v’, v", φ, φp), Ta 13(1) (p’, p", tc’, tc", ft ’, ft", u’, u", a’, a", pl’, pl", vs, ω). Setae d of tibia, (p), (tc) and (ft) of tarsus are eupathidia. Seta k 8 needle-like. Solenidion ω 27, finger-shaped; solenidion φp 31 attenuate. solenidion φ 10 baculiform. Tarsal setae vs, (pl) weakly barbed, other tarsal setae smooth. Leg II ( Figure 25B ). Leg setation: Tr 1 (v’), Fe 5 (d, l’, l", v’, bv"), Ge 4 (d, l’, l", k), Ti 5(1) (d, l’, l", v’, v", φp), Ta 9(1) (p’, tc’, tc", u’, u", a’, a", pl’, vs, ω). Setae p’, tc’ of tarsus and d of tibia are eupathidia. Solenidion ω 17 finger-shaped; solenidion φp 25 attenuate. Tarsal setae pl’, vs and (a) weakly barbed, other tarsal setae smooth. Leg III ( Figure 26A ). Leg setation: Tr 2 (l’, v’), Fe 3 (d, l’, ev’), Ge 1 (d), Ti 5(1) (d, l’, l", v’, v", φp), Ta 7(1) (tc’, tc", u’, u", a’, a", vs, ω). Solenidion ω 8 baculiform; solenidion φp 20 attenuate. Seta (tc) of tarsus smooth, other tarsal setae barbed. Leg IV ( Figure 26B ). Leg setation: Tr 1 (v’), Fe 2 (d, ev’), Ge 1 (d), Ti 5(1) (d, l’, l", v’, v", φp), Ta 7(1) (tc’, tc", u’, u", a’, a", vs, ω). Solenidion ω 8 baculiform; solenidion φp 20 attenuate. Setae d of tibia long and smooth. Setae (tc) of tarsus smooth, other tarsal setae weakly barbed.

Male and immatures unknown.

Type material — Female holotype, slide AT260115 /S, Chile, the Region of Magallanes, Nothofagus forest, in Sphagnum sp. , 53°41’08.8"S, 70°58’24.2"W, 26 January 2015, coll. A.V. Tolstikov.

Etymology — The name of the new species refers to its distribution in Patagonia.

Differential diagnosis — The new species is most similar to S. flexisetus n. sp., by smooth dorsal plates, presence of eyes, long and flexible dorsal setae ve, sce, c 2, e 2 and f 1. However, it differs from the latter by much shorter and blunt-ended setae c 1, d 1 and e 1 (vs. much longer and pointed in S. flexisetus ), presence of seta d on genu III (vs. absent in S. flexisetus ), presence of seta d on genu II (vs. absent in S. flexisetus ).

Figures

FIGURE 23: Stigmaeus patagoniensis n. sp., female: A – idiosomal dorsum, B – idiosomal venter.

FIGURE 24: Stigmaeus patagoniensis n. sp., female: A – gnathosoma dorsally, B – subcapitulum.

FIGURE 25: Stigmaeus patagoniensis n. sp., female: A – leg I, B – leg II.

FIGURE 26: Stigmaeus patagoniensis n. sp., female: A – leg III, B – leg IV.