Sinhomidia bicolor, (YOSII, 1965)

Zhang, Feng, Deharveng, Louis, Greenslade, Penelope & Chen, Jian-Xiu, 2009, Revision of Acanthocyrtus (Collembola: Entomobryidae), with description of a new genus from eastern Asia, Zoological Journal of the Linnean Society 157 (3), pp. 495-514 : 510-513

SINHOMIDIA BICOLOR ( YOSII, 1965) ( FIG. 10 )

Acanthocyrtus bicolor Yosii, 1965

Type locality: Wulai , Taiwan, China .

Specimens examined: Female, China: Anhui: Huangshan Mountain , 29 °42′N, 118 °18′E, 5.ix.1999, collection number 9106, collected by Ma Yitong ; three females, Anhui: Qimen: Penglong: Likou Village , 29 °51′N, 117 °43′E, 16.viii.2004, collection number 9205, Qu Jiqiang and Zhang Feng ; two females, Anhui: Yixian: Mukeng , 29 °56′N, 117 °56′E, 20.viii.2004, Qu Jiqiang, Zhang Feng, and Yan Haijuan ; one female, Anhui: Qimen: Luxi: Bao Village , 29 °52′N, 117°43′E, 11.viii.2005, collection number 9284, collected by Qu Jiqiang and Chen Jianxiu.

Description: Body length up to 3.2 mm.

Colour pattern. Ground colour pale yellow in alcohol. Eye patches dark purple. Antennae pigmented and gradually darker towards tip of each segment. Deep purple pigment present on mesothorax laterally, whole Abd. II and III, Abd. IV medially and posteriorly, and manubrium. Hind leg with scattered pigment but femur and tibiotarsus pale ( Fig. 10A ).

Head. Eyes eight + eight, G and H smaller and subequal. Antenna 2.7–3.6 times as long as cephalic diagonal. Ratio of segments of antennae I: II: III: IV = 1.0: 1.3–1.7: 1.0–1.6: 1.8–3.2. Antenna I and II scaled. Ant . IV annulated and bilobed.

Labral papillae absent. Prelabral and labral setae four/five, five, four; prelabral setae smooth; the three media setae of the first row distinctly larger than others ( Fig. 10B ). Lateral process straight, as thick as normal setae, with tip just not reaching apex of same labial papilla ( Fig. 10C ). Basal setae of labium as M1M2REL1L2; M2 and R are two microchaetae; E and L1 smooth ( Fig. 10D ). Cephalic dorsal chaetotaxy as four An, four M, five S macrochaetae; interocular area with setae prt ( Fig. 10E ).

Thorax. Dorsal macrochaetae shown in Figure 10F . Th. II – all the macrochaetae displaced anteriorly from the normal position; 16–19 posterior; three (m1, m2, and m2i) mediomedial; 3 (m4, m4i, and m4p) mediosublateral. Th. III – 9–11 central; m5i and a6i absent.

Trochanteral organ with numerous smooth spiny setae. Tibiotarsus with inner differentiated setae ciliate, the distal one smooth. Tibiotarsal inner outstanding macrochaetae acuminate but tapered only at tip ( Fig. 10G ). Unguis with one outer, two lateral, and four inner teeth; outer one small near the base of unguis, and much smaller than lateral ones; paired inner teeth with tip reaching 0.31–0.48¥ internal length of claw, median one at 0.61–0.73¥, and distal one at 0.87–0.91¥ distance from base. Unguiculus acuminate with outer edge slightly serrate. Tenent hair clavate, slightly longer than unguiculus and shorter than unguis ( Fig. 10H ).

Abdomen. Abd. III 8–11 times as long as Abd. III along dorsal midline. Dorsal chaetotaxy and corresponding bothriotrichial complex shown in Figure 10F, I–K . Abd. I – four (m2, m3, m4, and m4i) on each side; m4i sometimes absent. Abd. II – five central and one (m5) lateral. Abd. III – one (m3) dorsocentral and four (am6, pm6, p6, and m7) lateral. Abd. IV – in all 27–34 dorsocentral and about 23 lateral, 13–16 macrochaetae present in one row anteriorly. The bothriotrichial complex of Abd. II –IV is well developed; consisting of numerous accessory microchaetae, ranging from only slightly modified microchaetae to modified setulae, or few small scales ( Fig. 10 , I–K). Tenaculum with four + four teeth and one large striate seta ( Fig. 10L ). Ventral tube anteriorly with three + three large and many small ciliate setae and translucent scale-like setae ( Fig. 10M ); posteriorly with six apical smooth setae besides numerous ciliate setae of different sizes ( Fig. 10N ); lateral flap with 14 smooth and about 14 ciliate setae ( Fig. 10O ). Furcal segmental ratio of manubrium to dens plus mucro = 1: 1.17–1.33. Manubrium covered with scales and ciliate setae ventrally, and only ciliate setae dorsally. Manubrial plaque with three larger, seven smaller setae, and three pseudopores ( Fig. 10P ). Dens with spines arranged in one row ( Fig. 10Q ); scales absent ( Fig. 10S ). Smooth portion of dens shorter than mucro in length. Mucronal apical tooth smaller than antiapical one. Mucronal basal spine short with tip just beyond apex of anteapical tooth ( Fig. 10R ). Male genital plate not seen.

Body scales. Scales narrow, pointed and fusiform with coarse striations ( Fig. 10T ), present on Ant . I– II, head, thorax, abdomen, manubrium ventrally; scales on ventral manubrium much narrower than those on body ( Fig. 10U ).

Ecology: Found in leaf litter, debris, and rotten logs of evergreen broad-leaved forest, where a subtropical monsoon climate predominates.

Remarks: Acanthocyrtus bicolor was originally described by Yosii (1965) from juvenile individuals, and redescribed by Lee & Park (1989) from adults in the type locality. Our specimens agree with the above authors’ descriptions in all examined features (body colour pattern, dorsal chaetotaxy, dental spines, mucro). We add more details on the lateral process of labial palp, setae on labial base, complete dorsal chaetotaxy, lateral flap, and manubrial plaque.

The macrochaetae on Abd. IV are anteriorly arranged in an unusual transverse row of setae as in the case of the genus Homidia . The macrochaetae on the central thorax are abundant with complex patterns so that it was not possible to determine their homology.

Figures

Figure 10. Sinhomidia bicolor (Yosii). A, colour pattern. B, prelabral and labral setae. C, lateral process of labial palp. D, labial triangular setae. E, cephalic dorsal chaetotaxy. F, body chaetotaxy. G, tibiotarsal inner differentiated setae. H, hind claw. I, bothriotrichial complex on abdominal segment (Abd.) II. J, bothriotrichial complex on Abd. III. K, bothriotrichial complex on Abd. IV. L, tenaculum. M, anterior face of ventral tube. N, posterior face of ventral tube. O, lateral palp. P, manubrial plaque. Q, dental spines. R, mucro. S, dens. T, body scales. U, scales on ventral manubrium. Scale bars: A and F = 1 mm; B–E, G–U = 50 Mm.