Eustigmaeus chilensis ( Chaudhri, 1965 )

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 : 646-651

Eustigmaeus chilensis ( Chaudhri, 1965)

( Figures 6-10 )

Ledermuelleria chilensis Chaudhri, 1965, p. 471 , figs. 3, 4, 26.

Redescription

Female ( Figures 6-10 ) — Idiosoma oval in outline. Length of idiosoma (measurements for 5 specimens) 390 – 435, width 310 – 320.

Idiosomal dorsum ( Figures 6A , 10A, B ) — Idiosoma completely covered by 3 well sclerotized plates. Plates with large oval dimples and numerous tiny alveoli inside dimples ( Figures 10A, B ); subcuticular reticulation indistinct. Dorsal setae long, curved, smooth or with few minute barbs, situated on distinct protuberances ( Figures 10A, B ). Suranal plate and setae h 1 and h 2 situated dorsally. Setae h 1 and h 2 more distinctly barbed than other hysterosomal setae. Lengths of dorsal setae: vi 82 – 98, ve 90 – 95, sci 75 – 81, sce 77 – 86, c 1 75 – 78, c 2 76 – 92, d 1 85 – 90, d 2 80 – 90, e 1 88 – 95, e 2 84 – 87, f 1 81 – 83, h 1 58 – 60, h 2 49 – 53.

Idiosomal venter ( Figures 6B , 10D, E ) — Callosities absent. Endopodal plates fused medially, with weak subcuticular reticulate ornamentation ( Figure 10D ). Humeral plate subtriangular, with distinct large dimples. Most of ventral setae smooth or weakly barbed; with 1 pair of smooth aggenital, and 3 pairs of distinctly barbed pseudanal setae; setae ps 1 slightly thicker than other pseudanal setae ( Figure 10E ). Lengths of ventral setae: 1 a 21 – 23, 1 b 22 – 25, 1 c 18 – 20, 2 b 19 – 22, 2 c 18 – 19, 3 a 19 – 24, 3 b 18 – 20, 3 c 19 – 21, 4 a 21 – 23, 4 b 16 – 19, 4 c 17 – 19, ag 1 19 – 21, ps 1 22 – 25, ps 2 17 – 19, ps 3 17 – 19.

Gnathosoma ( Figures 7 , 10C, F ) — Tibial claw well-developed. Setae of palpal femur slightly thickened and distinctly barbed; other palpal setae of genu and tibia (except l’Ti) weakly barbed; seta l’ of tibia very thick, lanceolate; seta va of palptarsus weakly barbed; other 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 segments without reticulation. Palpal supracoxal setae (ep) needle-like. Rostrum of subcapitulum short and wide. All subcapitulat setae pointed and weakly barbed. Basal part of subcapitulum without subcuticular reticulation ( Figure 10F ). Lengths of subcapitular setae: m 24 – 25, n 20 – 21, or 1 19 – 21, or 2 20 – 21. Chelicerae dorsally smooth ( Figure 10C ).

Legs ( Figures 8 , 9 ) — Empodial raylets weakly capitate. Leg I ( Figure 8A ). Leg segments without reticulation. Coxae I posterodorsally with needlelike leg supracoxal setae (el). 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), T a 13(1) (p’, p", tc’, tc", ft’, ft", u’, u", a’, a", pl’, pl", vs, ω). Setae (p), (tc) and (ft) of tarsus are eupathidia. Setae d, l’, l" of tibia and genu, d and l" of femur distinctly widened, curved, barbed. Seta k 7 – 8 long, needle-like, about five times shorter than seta d of genu I. Solenidion ω 23 – 25 long, finger-shaped; solenidia φ 10 and φp 16 baculiform. All setae of tarsus (except eupathidia) barbed. Leg II ( Figure 8B ). Leg setation: Tr 1 (v’), Fe 5 (d, l’, l", v’, bv"), Ge 3 (d, l’, l"), Ti 5(1) (d, l’, l", v’, v", φ), Ta 8(1) (tc’, tc", u’, u", a’, a", pl’, vs, ω). Seta tc’ of tarsus represented by eupathidion. Seta p’ absent. Seta k of genu absent. Setae d, l’, l" of tibia and genu, d and l" of femur distinctly widened, curved, barbed. Solenidion ω 15 – 17 finger-shaped; solenidion φp 12 – 13 baculiform. All setae of tarsus (except eupathidion) barbed. Leg III ( Figure 9A ). Leg setation: Tr 2 (v’, l’), Fe 3 (d, l’, ev’), Ge 1 (d), Ti 5(1) (d, l’, l", v’, v", φ), Ta 7(1) (tc’, tc", u’, u", a’, a", vs, ω). Solenidion ω 5 – 6 baculiform; solenidion φp 7 – 8 baculiform. Setae d, l’, l" of tibia, d of genu, d and l’ of femur distinctly widened, curved, barbed. All setae of tarsus barbed. Leg IV ( Figure 9B ). Leg setation: Tr 1 (v’), Fe 2 (d, ev’), Ge 1 (d), Ti 5(1) (d, l’, l", v’, v", φ), Ta 7 (tc’, tc", u’, u", a’, a", vs). Solenidion ω absent; solenidion φp 7 – 9 baculiform. Setae d, l’, l" of tibia, d of genu and femur distinctly widened, curved, barbed. All setae of tarsus barbed.

Male and immatures unknown.

Material examined — Eleven females, Chile, Patagonia , Tierra del Fuego island, 54°29’550" S, 068°43’103" W, from Sphagnum magellanicum in the swamp, 3 November 2015, coll. A.A. Khaustov.

Distribution — This species was described from Chile (Jardin Botanico Nacional, Vina del Mar) ( Chaudhri 1965). It was also recorded from Latvia and Lithuania ( Kuznetsov and Petrov 1984) and Turkey (Do ˘gan 2007). However records of E. chilensis from Latvia, Lithuania and Turkey would need confirmation. This species is first time recorded in the fauna of Tierra del Fuego.

Figures

FIGURE 6: Eustigmaeus chilensis (Chaudhri, 1965), female: A – idiosomal dorsum, B – idiosomal venter.

FIGURE 7: Eustigmaeus chilensis (Chaudhri, 1965), female: A – gnathosoma dorsally, B – subcapitulum.

FIGURE 8: Eustigmaeus chilensis (Chaudhri, 1965), female: A – leg I, B – leg II.

FIGURE 9: Eustigmaeus chilensis (Chaudhri, 1965), female: A – leg III, B – leg IV.

FIGURE 10: Phase-contrast micrographs of Eustigmaeus chilensis (Chaudhri, 1965), female: A – anterolateral part of prodorsum, B – seta d1, C – gnathosoma dorsally, D – ventral metapodosomal plate, E – anogenital area, F – subcapitulum.