Unguidispus polyctenus (Sevastianov, 1969)

Khaustov, Alexander A., 2014, A review of myrmecophilous mites of the family Microdispidae (Acari, Heterostigmatina) of Western Siberia, ZooKeys 454, pp. 13-28 : 15

Taxon classification Animalia Prostigmata Microdispidae

Unguidispus polyctenus (Sevastianov, 1969) Figs 1, 2, 3, 4

Piniphorus polyctenus Sevastianov, 1969, p. 68, fig. 2.

Xystrorostrum polyctenus : Mahunka 1970a: 165.

Unguidispus polyctenus : Mahunka 1970b: 282.

Redescription.

Female Length of idiosoma 190-205, width 120-135.

Gnathosoma (Figs 1, 4E, 4F). Gnathosomal capsule beak-like, about 1.5 times longer than its width. Dorsally with two pairs of smooth subequal setae (cha, chb). Dorsal median apodeme absent. Ventral gnathosoma with one pair of subcapitular setae m and a pair of oval pits situated posteromedial to bases of m. Palps with setae dFe and dGe dorsolaterally. Setae dGe slightly longer than dFe. Ventral palpal structures not evident even on SEM photos (Fig. 4F). Palps terminated with a relatively long and thin tibial claw (Fig. 4F).

Idiosomal dorsum (Figs 1A, 4A). Prodorsum almost completely covered by anterior margin of tergite C, with one pair of setae sc2, one pair of clavate and weakly barbed trichobothria sc1 with pointed apex, and one pair of large round stigmata. All dorsal shields smooth. All dorsal setae distinctly barbed; setae d and f blunt-ended, other dorsal setae pointed. Posterior margin of tergite C straight; posterior margin of tergite H with tongue-like elongation medially. Cupules ia on tergite D and ih on tergite H small, round. Lateral shields covering lateral parts of tergite D with distinct sclerotized lines (Fig. 4B). With a pair of arch-like structures anteriorly to setae f and a pair of oblique ridges connected to bases of setae e (Fig. 4C). Length of dorsal setae: sc2 12-14, c1 35-38, c2 40-42, d 36-38, e 44-45, f 35-37, h1 40-45, h2 35-37. Distances between setae: sc2-sc2 37-40, c1-c1 47-50, c1-c2 22-24, d–d 41-43, e–f 18-20, f–f 35-38, h1-h1 19-21, h1-h2 18-21.

Idiosomal venter (Figs 1B, 4D). All ventral figs smooth. All ventral setae pointed and barbed, except smooth ps3. Apodemes 1 (ap1) weakly developed and joined with prosternal apodeme (appr); apodemes 2 (ap2) well developed, arch-like, fused with appr; prosternal and sejugal (apsej) apodemes well developed; apodemes 3 (ap3) well sclerotized. Apodemes 4 (ap4) well sclerotized and long, apodemes 5 absent. Posterior margin of posterior sternal fig slightly convex in middle part. Posterior margin of aggenital fig rounded. Anterior genital sclerite (ags) bell-like, posterior genital sclerite (pgs) very small, triangular. Length of ventral setae: 1a 35-37, 1b 21-23, 2a 33-36, 2b 36-40, 3a 34-36, 3b 35-37, 3c 36-38, 4a 36-38, 4b 52-55, 4c 39-41, ps1 24-26, ps3 9-11.

Legs (Figs 2-3, 4F). Leg I (Figs 2A, 4F) distinctly shorter and thinner than leg II. Setal formula: 1 –3–4– 16(4). Tibiotarsus not thickened, with well-developed terminal claw situated on distinct pretarsus, tip of the claw thin. Length of solenidia ω 1 11-12 = ω 2 11-12> φ 1 6-7 = φ 2 6-7; ω 1 and ω 2 finger-shaped, φ 2 baculiform, φ 1 clavate. Setae (u) fused into structure opposing to tarsal claw. Leg II (Fig. 2B). Setal formula: 1 –3–3–4(1)– 6(1). Tarsus with sickle-like, padded claws and large empodium. Solenidion ω 9-10, finger-shaped, solenidion φ 3-4 weakly clavate. Seta dFe distinctly blunt-ended. Leg III (Fig. 3A). Setal formula: 1 –2–2–4(1)– 6. Claws of same shape as on tarsus II. Solenidion φ 3-4 weakly clavate. Seta dFe distinctly blunt-ended. Leg IV (Fig. 3B). Setal formula: 1 –2–1–4(1)– 6. Tarsus long and thin, pretarsus short, with two small simple claws and small empodium. Solenidion φ 3-4, weakly clavate. Seta dFe distinctly blunt-ended.

Male and larva unknown.

Material examined.

Eight female paratypes, Ukraine, Khmelnitsk Province, vicinity of settlement Chemerovtsy, on ants Formica polyctena Forster, 23 July 1966, coll. V.D. Sevastianov; 3 females, Russia: Tyumen Province, vicinity of Tyumen, 57°04'03"N, 65°04'12"E, on ants Formica rufa L., 17 August 2014, coll. A.A. Khaustov; 15 females, Russia, Tyumen Province, vicinity of Tyumen, 57°13'43.6"N, 65°28'28.4"E, on ants Formica polyctena , 14 September 2014, coll. A.A. Khaustov.

Distribution and hosts.

This species was described from Western Ukraine from ants Formica polyctena Forster ( Sevastianov 1969). It was also recorded in northwestern Russia ( Sevastianov 1978), Austria ( Mahunka 1970b) from ants Formica rufa L., and in Hungary from ant nest ( Mahunka 1987).

Remarks.

Sevastianov (1969) placed this species in the genus Piniphorus Sevastianov, 1969. Mahunka (1970a) transferred it to Xystrorostrum Mahunka, 1968 ( Neopygmephoridae ) which he considered as a senior synonym of Piniphorus . The same year Mahunka (1970b) moved this species to the microdispid genus Unguidispus Mahunka, 1970. In spite of this, Sevastianov (1978) retained it in the neopygmephorid genus Xystrorostrum .

The original description of Unguidispus polyctenus of Sevastianov (1969) is incomplete, thus I made a redescription of this species. The present redescription of Unguidispus polyctenus is based mainly on material from Western Siberia. The female paratypes available for this study are found in bad condition, yet sufficient to prove their identity with mite specimens from Western Siberia.