Sinella yui sp. nov.

Figs 2, 20–33

Types. Holotype: male on slide, China: Zhejiang: Qinyuan: Baishanzu town, 27°44’21.82’’N, 119°10’43.42’’E, 21.v.2011, F. Zhang and D.- Y. Yu leg. (sample number C9659). Paratypes: 1 female on slide, same data as holotype.

Description. Body length up to 1.48 mm. Body yellow white (Fig. 2).

Antenna 2.5 times as long as cephalic diagonal. Antennal segments ratio as I: II: III: IV = 1: 1.4: 1. 9: 3.0. Long smooth straight chaetae ventral, 1 and 2 on Ant.I and II respectively. Two internal S of Ant.III organ rod-like.

Omma 3+3, anterior two and posterior one separate. Papilla E with 4 guard chaetae; lateral process of labial palp much thicker than normal chaetae (Fig. 20). Labial chaeta R ciliate and others smooth, R/M=0.45; chaetae X, X2 and X4 ciliate. Cephalic groove with 8 chaetae, 4 of them smooth (Fig. 22). Dorsal cephalic chaetotaxy with 3 median (M) mac (Fig. 23). Clypeal chaetae smooth but their number and arrangement not clearly seen.

Trochanteral organ with about 16 smooth spiny chaetae; 11 in arms and 5 between them (Fig. 24). Inner differentiated tibiotarsal chaetae ciliate with ciliations not closely appressed to axis. Unguiculus outer edge smooth. Tenent hairs pointed, subequal to unguiculus in length (Fig. 25). Abd.IV 4.0 times as Abd.III in length along dorsal midline. Ventral tube anteriorly with 6 ciliate chaetae on each side and 2 of them much larger (Fig. 26); posteriorly with about 12 smooth chaetae (Fig. 27); each lateral flap with 7 smooth chaetae. Manubrium without smooth straight chaetae, most distal part with 5+5 anterior and 4+4 posterior ciliate chaetae in a row. Manubrial plaque with 3 pseudopores and 3 ciliate chaetae (Fig. 28). Distal smooth part of dens subequal to mucro in length. Mucronal basal spine long with tip reaching the middle between two teeth; apical tooth longer than subapical one (Fig. 29).

Th.II with 3 medio-medial (m1, m2, m 2i), 3 medio-lateral (m4, m 4i, m4p) and 21–22 posterior mac; p5 as mac. Th.III with 31 mac (Fig. 30). Abd.I with 6 (m2–4, a3, m 2i, m4p) mac. Abd.II with 4 (a2, m3, m3e, m3ep) central and 1 (m5) lateral mac. Abd.III with 1 (m3) central and 3 (am6, pm6, p6) lateral mac; ms absent (Fig. 31). Abd.IV with 7 central (I, M, A4, A6, B4–6), 6 lateral mac (D3, F1, E2–4, E2p); most s-chaetae much longer than those on anterior terga but their number not clearly seen (Fig. 32). Abd.V with 3 s-chaetae (Fig. 33).

Ecology. Under bricks and moss.

Etymology. Named after Mr. Yu who helped to collect the animals.

Remarks. This new species is similar to 3+3 eyed S. pseudostraminea Stach, 1965 from Vietnam, S. straminea Folsom, 1899 and S. triocula Chen & Christiansen, 1993 from China. It differs from S. pseudostraminea in less spiny chaetae on trochanteral organ, chaetotaxy of Abd.II and IV, and larger apical tooth on mucro. It differs from the latter two Chinese species in smooth outer edge on unguiculus, long mucronal basal spine, pointed tenent hairs, and tergal chaetotaxy.