Scutacarus rotundus ( Berlese, 1903 )

Khaustov, A., 2015, Mites of the family Scutacaridae (Acari: Pygmephoroidea) associated with Formica fusca L. (Hymenoptera: Formicidae) from Western Siberia, Russia, Acarologia 55 (4), pp. 377-386 : 381-382

Scutacarus rotundus ( Berlese, 1903)

( Figures 4-6 )

Disparipes silvestri var. rotundus Berlese, 1903, p. 23 . Disparipes rotundus: Paoli 1911, p. 240 , Figs. 27, 28. Scutacarus rotundus: Karafiat 1959, p. 696 .

Redescription

Female — Length of idiosoma 230 – 260, width 205 – 230.

Gnathosoma — as in S. karafiati n. sp.

Idiosomal dorsum ( Figures 4A , 6 ) — Prodorsum completely covered by tergite C, with two pairs of smooth needle-like setae v 2 and sc 2, one pair of barbed capitate trichobothria, and one pair of oval stigmata. All dorsal shields with numerous small dimples. Cupules ia on tergite D and ih on tergite H large, round. Setae c 1, c 2, d and f thick, blunt-ended and distinctly barbed; setae e and h 2 pointed, curved medially and sparsely barbed; setae h 1 sparsely barbed and curved medially. Posterior margin of tergite EF weakly undulate. Lengths of dorsal setae: c 1 39 – 41, c 2 39 – 41, d 43 – 45, e 55 – 57, f 76 – 87, h 1 14 – 15, h 2 47 – 53. Distances between setae: c 1 – c 1 59 – 63, d – d 120 – 135, f – f 88 – 100, h 1 – h 1 61 – 63.

Idiosomal venter ( Figure 4B ) — All ventral plates with numerous small dimples. Ap1 welldeveloped and joined with appr, ap2 w-like, joined with appr; apsej well developed and joined with appr. Secondary transverse apodeme well developed. Ap3 weakly developed, diffuse, ap4 short, joined with appo. Ap5 diffuse, fused with appo. Setae 2 b slightly thickened, smooth, blunt-ended, setae 4 a smooth, situated on the same level as 4 b and reaching distinctly beyond posterior margin of poststernal plate, setae ps 3 short and smooth, other ventral setae sparsely barbed. Distance 4 a – 4 a equal to 4 a – 4 b. Anterior genital sclerite tongue-like, posterior genital sclerite triangular. Lengths of ventral setae: 1 a 41 – 44, 1 b 36 – 41, 2 a 34 – 37, 2 b 25 – 28, 3 a 41 – 42, 3 b 44 – 47, 3 c 49 – 53, 4 a 23 – 27, 4 b 93 – 115, 4 c 62 – 67, ps 1 31 – 36, ps 2 27 – 30, ps 3 6 – 7.

Legs ( Figure 5 ) — Shape and setation of leg I similar to that of S. karafiati n. sp. Lengths of solenidia: ω 1 12> ω 2 8 – 9> φ 1 9 – 10 <φ 2 6 – 7; ω 2 and φ 2 baculiform, φ 1 clavate, ω 1 finger-shaped ( Figure 5A ). Seta dFe flattened, with several large barbs. Setae l’ of femur blunt-ended and smooth. Leg II as in S. karafiati n. sp. Solenidion ω 11 finger-shaped, solenidion φ weakly clavate. Setae pl" spine-like, barbed, u’ blunt-ended and barbed in distal half. Leg III as in S. karafiati n. sp. Solenidion φ weakly clavate. Setae pl" spine-like, barbed, u’ blunt-ended and barbed in distal half. Leg IV ( Figure 5B ). Leg chaetotaxy as in S. karafiati n. sp. Setae d of femur blunt-ended. Tibiotarsus short, only slightly longer than its width. Setae tc" distinctly longer than pv’.

Male and larva unknown.

Material examined — Four females, Russia, Tyumen Province, vicinity of Tyumen, 57°13’43.6" N, 65°28’28.4" E, on ants Formica fusca , 13 September 2014, coll. A.A. Khaustov ; 2 females, Russia, Tyumen Province, Uvat region, vicinity of settlement Demyanka , 59°31’35" N, 69°57’47" E, on ants Formica fusca , 22 August 2014 , coll. V. A. Stolbov; 3 females, Russia, Tyumen Province, Tyumen region, vicinity of Tyumen, 57°04’03" N, 65°04’12" E, on ants Formica fusca , 17 August 2014, coll. A.A. Khaustov.

Remarks — This species was originally described from Italy ( Berlese 1903) from ants Formica fusca . It was also recorded from Germany from Formica fusca and Lasius niger (Linnaeus, 1758) ( Karafiat 1959) ; Austria from Formica rufa L., 1761 ( Mahunka 1970); Hungary ( Mahunka and Zaki 1984) and Ukraine ( Sevastianov 1978). This is a new record for the fauna of Russia.

Paoli (1911) studied specimens of S. rotundus in Berlese collection and provided redescription and illustrations of this species. Mahunka (1980) studied the type material of pygmephoroid mites in the Berlese collection and found out that the slide with a type specimen of S. rotundus was in a very bad condition. The other slide belonging to the type series of S. rotundus contained specimens of S. silvestri Berlese, 1903 and S. stammeri Karafiat, 1959 . Mahunka (1980) supposed that S. stammeri is a potential synonym of S. rotundus . Specimens from Western Siberia identified by me as S. rotundus completely fit to illustrations and description of S. rotundus provided by Paoli (1911) and clearly differ from S. stammeri .

Figures

FIGURE 4: Scutacarus rotundus (Berlese, 1903), female: A – idiosomal dorsum, B – idiosomal venter.

FIGURE 5: Scutacarus rotundus (Berlese, 1903), female: A – solenidia of tibiotarsus I, B – leg IV in ventral view.

FIGURE 6: Scanning electron micrograph of Scutacarus rotundus (Berlese, 1903), female: dorsum.