Sinella triseta, Yuan, Xiang-Qun & Pan, Zhi-Xiang, 2013

Yuan, Xiang-Qun & Pan, Zhi-Xiang, 2013, Two new species of Entomobryidae (Collembola) of Taibai Mountain from China, ZooKeys 338, pp. 67-81 : 74-79

Sinella triseta sp. n. Figures 22-40

Holotype.

1♀ on slide, Baoji City, Mei County, Haoping Temple manage department, Shaanxi Province, CHINA, 34°05.18'N, 107°42.08'E, sample number S4325, collected by Xiang-Qun Yuan, Zhi-Xiang Pan, 11.VII.2012.

Paratypes.

5♀, 1♂ on slide and 3 in alcohol, same data as holotype, all types deposited in School of Life Sciences, Taizhou University.

Etymology.

Named using the Latin words “tri+seta” (three mac on each side of posterior Abd. IV).

Description.

Body length up to 1.17 mm, white (Fig. 22).

Head. Antenna 1.27-1.61 times as long as cephalic diagonal. Antennal segments ratio as I: II: III: IV = 1: 1.67-2.05: 1.42-1.71: 1.95-3.28. Smooth spiny mic at base of antennae as 3 dorsal, 4 ventral on Ant. I (Fig. 24) and 4 on Ant. II (Fig. 25). Ant. III organ with 5 rod-like S-chaetae (Fig. 26). Ommatidia absent. Dorsal cephalic chaetotaxy with 4 antennal (An), 5 sutural (S) and 4 mac in Gr. II (Fig. 23). Clypeus with 7 chaetae arranged in two lines (4 ciliate and 3 smooth) (Fig. 27). Labral papillae absent; prelabral and labral chaetae as 4/5, 5, 4, all smooth; labial intrusion U-shaped (Fig. 28). Subapical chaeta of maxillary outer lobe shorter than apical one; 3 smooth sublobal hairs on maxillary outer lobe. Labial chaetae as MREL1L2, all smooth; chaeta R subequal to M; chaetae X and X4 as peg-like, smooth mic; chaetae X2 and X3 absent (Fig. 29). Five papillae A–E on labial palp with 0, 5, 0, 4, 4 guard chaetae, respectively. Lateral process (l.p.) of labial palp as thick as normal chaetae, with tip beyond apex of labial papilla E (Fig. 30). Mandible with 4/5 (left/right side) teeth.

Thorax. Complete body s as 22/122 (14-16) 3; ms as 10/10000. Th. II with 4 (m1, m2, m2i and m2i2) medio-medial, 3 medio-lateral (m4, m4i, m4p), 18-21 posterior mac and 3 S-chaetae (ms internal to s); p4 as mac, p5 and p6 as mic, p1i2 and p4i sometimes absent. Th. III with about 30 mac and 2 lateral S-chaetae; p5, p6 and a5e as mic, p4 rarely as mac (Fig. 31). Coxal macrochaetal formula as 3 (2 p)/4+1, 3 (2 p)/4+2 (2 p) (Fig. 32). Trochanteral organ with 8-12 smooth spiny chaetae; 5-11 in arms and 2-3 between them (Fig. 33). 3-4 inner differentiated tibiotarsal chaetae “smooth” with ciliations closely appressed to axis. Tenent hair all acuminate and subequal to inner edge of unguis. Unguis with 3 inner teeth, basal paired teeth unequal, outer one larger. Unguiculus acuminate with a large tooth on outer edge (Fig. 34).

Abdomen. Abd. IV 2.94-4.34 times as Abd. III in dorsal axial length. Abd. I with 6 (a3, m2-4, m2i, m4p) mac and 2 S-chaetae (ms antero-external to s). Abd. II with 3 (m3, m3e, m3ep) central, 1 (m5) lateral mac and 2 S-chaetae. Abd. III with 1 (m3) central, 3 (am6, pm6, p6) lateral mac and 2 S-chaetae (lateral ms absent) (Fig. 35). Abd. IV with 3 central (A6, B5 and anterior one homology uncleared mac), 4 lateral mac (F1, E2-4), 12-14 elongate and 2 normal S-chaetae. Abd. V with 3 obvious mac (m2, m3 and m5) and 3 S-chaetae (Fig. 36). Tenaculum with 4+4 teeth and one large basal chaeta. Anterior face of ventral tube with 5+5 ciliate chaetae (Fig. 37); posterior with 2+2 basal weekly ciliate and 2+2 subapical smooth chaetae, an additional smooth chaeta sometimes present between basal and apical region; lateral flap with 7-8 smooth chaetae, among them 0-2 weekly ciliated among them (usually unclear under light microscope) (Fig. 38). Manubrium without smooth chaetae. Manubrial plaque with 2 pseudopores and 3 ciliate chaetae (Fig. 39). Distal smooth part of dentes approximately 2 times as mucro in length. Mucro bidentate with basal spine long with tip reaching apex of apical tooth (Fig. 40).

Ecology.

Found under stones in forest, altitude 1185 ± 10 m.

Remarks.

This new species is characterized by 3 mac on posterior middle Abd. IV, ommatidia absent, labial base chaeta R subequal to M in length, X2 and X3 on ventral side of head absent, Abd. I–III with 6, 4, 4 mac, respectively, and clypeus with 7 mac arranged in two lines.

This species is most similar to Sinella yunnanica Zhang & Deharveng, 2011 in colour pattern, without ommatidia, claw, mucro, lateral process of labial palp, manubrial plaque and chaetotaxy of head and Th. II–Abd. III. However, it differ from latter in labial base chaeta R subequal to M (obviously short in the latter), X2 absent (present in the latter), 3 central mac on Abd. IV (5 in the latter), ventral tube with 5+5 mac on anterior face (about 8 in the latter) and 8-9 smooth chaetae on posterior face (12 in the latter). Also, this new species is similar to Sinella colorata Zhang et al. 2010 and Sinella pauciseta Qu et al. 2010 in 3 mac on posterior median Abd. IV, detailed differences between them are listed in Table 2.