Pseudostigmaeus magellani, 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 : 668-673

Pseudostigmaeus magellani n. sp.

( Figures 27-30 )

Description

Female ( Figures 27-30 ) — Length of idiosoma 480, width 260.

Idiosomal dorsum ( Figure 27A ) — Idiosoma fusiform, soft, mostly striated. Eyes present. Propodosomal plate smooth, with three setae: vi, ve and sci, with weak median propodosomal apodeme. Area anteriorly and anterolaterally to propodosomal plate with numerous microtubercles. All dorsal setae weakly barbed; setae ve, sci, sce and c 2 pointed; other dorsal setae blunt-ended. Setae c 2 situated dorsally. Ratio ve/sci = 3. Suranal plate not divided, with two pairs of setae. Other dorsal hysterosomal setae situated on platelets. Lengths of dorsal setae: vi 35, ve 105, sci 35, sce 80, c 1 32, c 2 105, d 1 33, d 2 43, e 1 42, e 2 36, f 1 55, h 1 46, h 2 55.

Idiosomal venter ( Figure 27B ) — Ventral setae smooth or weakly barbed; setae ps 1-3 blunt-ended, other ventral setae pointed. Three pairs of aggenital setae; ag 1 situated on soft cuticle; ag 2 – ag 3 on weakly defined platelet. One pair of genital setae. Cuticle posteriad to gnathosomal base, posterolaterad to coxae IV and transverse striae between coxae II and III with microtubercles. Endopodal plates weakly developed. Coxal fields with small dimples. Lengths of ventral setae: 1 a 41, 1 b 37, 1 c 59, 2 b 75, 2 c 60, 3 a 67, 3 b 32, 3 c 29, 4 a 43, 4 b 27, 4 c 19, ag 1 33, ag 2 47, ag 3 68, g 77, ps 1 33, ps 2 28, ps 3 30.

Gnathosoma ( Figure 28 ) — Tibial claw large. Setae l’ of palpal tibia thin, seta-like. All palpal setae pointed; setae of femur, genu and l" of tibia weakly barbed. Number of setae on palpal segments: Tr 0, Fe 3 (d, l’, v"), Ge 1 (d), Ti 3 (d, l’, l"), Ta 8(1) (fused eupathidia ul’, ul", sul, eupathidion acm, ba, bp, lp, 1 solenidion ω). Tarsal eupathidia ul’, ul" and sul almost completely fused, without distinct distal prongs. Palpal supracoxal setae (ep) small, spinelike. Chelicerae dorsally with numerous small dimples. Rostrum of subcapitulum long. Subcapitular setae pointed; n smooth and very long, other subcapitular setae barbed. Basal part of subcapitulum without reticulation. Lengths of subcapitular setae: m 42, n 115, or 1 24, or 2 23.

Legs ( Figures 29 – 30 ) — Empodial raylets distinctly capitate. Leg segments without reticulation. Leg I ( Figure 19A ). Coxae I posterodorsally with small, spine-like 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(1) (d, l’, l", v’, v", 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 5 needle-like. Solenidion ω 22 finger-shaped; solenidion φp 23 attenuate. solenidion φ absent. Setae (pl) and vs of tarsus weakly barbed; other tarsal setae smooth. Leg II ( Figure 29B ). Leg setation: Tr 1 (v’), Fe 4 (d, l’, l", bv"), Ge 2 (l’, l"), Ti 5(1) (d, l’, l", v’, v", φp), Ta 9(1) (p’, tc’, tc", u’, u", a’, a", pl’, vs, ω). Solenidion ω 21 finger-shaped; solenidion φp 19 attenuate. Seta pl’ and vs weakly barbed, other tarsal setae smooth. Setae d of tibia and tc" of tarsus very long and smooth. Leg III ( Figure 30A ). Leg setation: Tr 2 (v’, l’), Fe 3 (d, l’, ev’), Ge 0, Ti 5(1) (d, l’, l", v’, v", φp), Ta 7(1) (tc’, tc", u’, u", a’, a", vs, ω). Solenidion ω 9 baculiform; solenidion φp 15 attenuate. Setae d of tibia and (tc) of tarsus very long and smooth. Seta vs and (a) of tarsus weakly barbed, other tarsal setae smooth. Leg IV ( Figure 30B ). 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 17 attenuate. Setae d of tibia and (ts) of tarsus very long and smooth. Seta vs and (a) of tarsus weakly barbed, other tarsal setae smooth.

Male and immatures unknown.

Type material — Female holotype, slide AT260115 /S1, 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 new species is named after Ferdinand Magellan, the first European explorer who sailed past southernmost tip of South America and discovered Patagonia in 1520.

Differential diagnosis — The new species differs from all known Pseudostigmaeus species by the absence of seta d of genu III and l" of palpal genu (vs. present in all known species).

Remarks — The genus Pseudostigmaeus Wood, 1967 includes four species, which were described from New Zealand ( Fan and Zhang 2005). This is the first report of the genus Pseudostigmaeus from South America.

Figures

FIGURE 27: Pseudostigmaeus magellani n. sp., female: A – idiosomal dorsum, B – idiosomal venter.

FIGURE 28: Pseudostigmaeus magellani n. sp., female: A – gnathosoma dorsally, B – subcapitulum.

FIGURE 29: Pseudostigmaeus magellani n. sp., female: A – leg I, B – leg II.

FIGURE 30: Pseudostigmaeus magellani n. sp., female: A – leg III, B – leg IV.

FIGURE 19: Stigmaeus flexisetus n. sp., female: A – leg III, B – leg IV.