Achipteria (Izuachipteria) setulosa (Golosova, 1981) Golosova, 1981

Maruyama, Ichiro, Bayartogtokh, Badamdorj & Shimano, Satoshi, 2016, Rediscovery of Achipteriasetulosa, with remarks on Japanese species of Achipteriidae and the proposal of species-groups (Acari, Oribatida), ZooKeys 578, pp. 1-13 : 2-4

Taxon classification Animalia Sarcoptiformes Achipteriidae

Achipteria (Izuachipteria) setulosa (Golosova, 1981) comb. n. Figs 1, 2

Achipteria setulosa Golosova, 1981: p. 148, fig. 1.

Achipteria setulosa : Pan’kov et al. 1997: p. 66; Bayartogtokh and Ryabinin 2012: p. 153.

Diagnosis.

Large species, body length: 718-796 μm; width: 480-576 μm (n = 10). Lamellar setae short, thin, smooth, inserted ventrally on cusps, not reaching tip of cusps; interlamellar setae short, thin, smooth, not reaching basis of lamellar cusps; sensilli long, club-shaped, epimeral regions III and IV with three setae each.

Measurement. Body length: 718-796 (759) μm; width: 480-576 (543) μm (n = 10).

Integument. Body color dark brown, heavily sclerotized species with minute microtubercles on lateral part of podosoma, exobothridial and lenticular regions. Granular cerotegument (with minute round to conical granular structure) clearly evident at base of prodorsum and on mentum.

Prodorsum (Fig. 1 A–C, E): Rostrum rounded, without horn-like anterior projection. Rostral setae (ro) long, barbed, curved inward, extending beyond tip of rostrum. Lamellae long and broad, fused medially; lamellar cusps nearly half as long as total length of lamellae, its anterior margin bending downwards, serrated irregularly as shown in Fig. 1A, B. Tutoria (tu) medium long, narrow, with free cusps distally. Lamellar setae (le) short (about 24 μm), thin, smooth, inserted ventrally on cusps, not exposed from cusps. Interlamellar setae (in) short, but slightly longer (about 35 μm) than lamellar setae, not reaching on base of lamellar cusps. Exobothridial setae not evident. Sensilli club-shaped, relatively long (about 102 μm), its head smooth (Fig. 1C). Bothridia nearly funnel-shaped, its opening exposed from anterior margin of notogaster.

Notogaster (Fig. 1 D–F): Longer than wide, anterior and posterior margins broadly rounded. Lenticular region irregularly pentagonal, with diffuse margins, but weakly visible and lacking true lenticulus. Anterior projection of pteromorphs pointed, not reaching level of rostrum (Fig. 1 D–F). Among 10 pairs of notogastral setae, la longest (35-42 μm), c next long setae (25-32 μm), other setae distinctly shorter (12-17 μm); relative length of mutual distances of setal pairs: la–la > h3-h3> c–c > p3-p3> lp–lp > lm–lm > h2-h2> p2-p2> p1-p1> h1-h1. Four pairs of sacculi clearly developed; Sa located anterolaterally to setae la, S1 between setae lp and h3, S2 anteriomediad of setae h2, and S3 anterolaterally to setae h1. Lyrifssures im situated posterolaterally to setae lm. Openings of opisthonotal glands (gla) located posterolaterlly to setae h3.

Gnathosoma (Fig. 1F): Subcapitulum nearly as long as wide, smooth throughout; setae h 37 μm, m 17 μm, and a 15 μm, smooth. Chelicerae chelate-dentate (178 μm), cheliceral setae long, barbed, cha (64 μm) longer than chb (35 μm). Palps typical for family (104 μm), formula of setation: 0 –2–1–3– 10 including solenidion ω on tarsus.

Epimeral and lateral podosomal regions (Fig. 1F): Genal teeth rectangular, with pointed tip. Pedotecta I with pointed anteromedial end as seen in ventral view, and even more sharply pointed in lateral view. Apodemes apo.2, apo.sj and apo.3 well developed. Epimeral regions III and IV with three setae each; epimeral setae 35-42 μm in length; 1c and 3d barbed, other setae smooth. Epimeral setal formula: 3 –1–3– 3. Custodia and discidia not clearly developed; circumpedal carinae poorly developed.

Anogenital region (Fig. 1F): Genital and aggenital setae long (36-43 μm), smooth; relative length of their mutual distances: g5-g5> g4-g4 ≥ g2-g2> g3-g3> g6-g6> g1-g1. Anal and adanal setae (13-18 μm) smooth; mutual distances of an1-an1 and an2-an2 almost equal; relative distances between anal and adanal setae: ad1-ad1> an1-an1> an2-an2 = an1-an1> ad1-ad1> ad2-ad2. Adanal lyrifissures (iad) aligned, almost parallel to anterolateral margins of anal aperture.

Legs (Fig. 2): Lateral claws thinner than middle one, having small, but distinct serrations on dorsal edge (Fig. 2G). Setation of legs typical for genus, most setae finely barbed except few distal or ventral setae on tarsi, femora and trochanters. Solenidia φ 1 on tibiae I about 2.8 times as long as φ 2; setae l" on genua I and II markedly thick; setae s on tarsi II very thick, bearing several strong branches; genua IV curved, markedly longer than others. Formula of setation, including famuli: I (1-5-3-4-20), II (1-5-3-4- 15), III (2-2-1-3-15), IV (1-2-2-3-12); formula of solenidia: I (1-2-2), II (1-1-2), III (1-1-0), IV (0-1-0); homology of setae and solenidia as indicated in Table 1.

Remarks.

The character states of the specimens examined here accord well with those studied by Golosova (1981). Only the slight differences are the scarcely barbed sensilli in the Russian specimens (smooth in Japanese specimens), and number of epimeral setae (Russian specimens has fewer setae than Japanese ones). Until now, the present species was known only from the type locality, Kuril Islands in the Russian Far East. The original description, illustration and differential diagnosis of this species were not sufficient, and hence we present here some supplementary details.

Achipteria (Izuachipteria) setulosa resembles the two other Japanese species, Achipteria (Izuachipteria) alpestris and Achipteria (Izuachipteria) imperfecta in having short and slender interlamellar setae. However, Achipteria (Izuachipteria) alpestris is different from Achipteria (Izuachipteria) setulosa by the strongly-developed median horn-like projection of the rostrum, the relatively shorter sensilli, and much smaller body size. Another Japanese species, Achipteria (Izuachipteria) imperfecta has no interlamellar setae, relatively thick sensilli, different dentation of lamellar cusps, and much smaller body size.