Sinella liuae, Zhao, Lina & Zhang, Feng, 2016

Zhao, Lina & Zhang, Feng, 2016, New cave species of Sinella Brook, 1882 from China (Collembola: Entomobryidae), Zootaxa 4161 (4), pp. 523-541 : 524-528

Sinella liuae sp. nov.

Figs 1 , 4‒23 , Table 1

Types. Holotype: female on slide, China: Guizhou Province: Qiandongnan: Shuiwei town: Changping village : Jiangjun cave, 109.016°E, 27.433°N, altitude 550 m, 28.vi.2014, Mingyi TIAN, Weixin LIU, Haowen YIN, Sunbin HUANG and Xinhui WANG leg . (collection # 15cave1). Paratypes: female on slide and 1 in alcohol, same data as holotype. All material deposited in NJAU .

Description. Body length up to 2.1 mm. Body whitish in alcohol ( Fig. 1 ).

Antennae 3.3‒3.6 times as long as cephalic diagonal. Antennal segments ratio as I: II: III: IV = 1: 1.8‒2.3: 2.0‒2.4: 3.8‒4.1. Smooth spiny mic at base of antennae: 3 dorsal, 3 ventral on Ant. I, 1 internal, 1 external and 2 ventral on Ant. II. Long smooth straight chaetae: 3 ventral on Ant. I and 4 ventral on Ant. II. Distal Ant. II with 1 paddle-like S-chaeta. Two internal S-chaetae of Ant. III organ paddle-like but not expanded; chaeta 8 dagger-like ( Fig. 4 ). Ant. IV with a knobbed subapical organ ( Fig. 5 ).

Eyes absent. Prelabral and labral chaetae 4/ 5, 5, 4, all smooth; median three chaetae of the first row longer than lateral ones. Eight clypeal chaetae arranged in three rows; three of them ciliate and smaller than others ( Fig. 6 ). Dorsal cephalic chaetotaxy with 4 antennal (An), 3 median (M) and 8 sutural (S) mac; Gr. II with 4 mac ( Fig. 7 ).

Mandibles with 4+5 (4 left, 5 right) large apical teeth. Subapical chaeta of maxillary outer lobe slightly thicker than apical one; 3 smooth sublobal hairs on maxillary outer lobe ( Fig. 8 ). Labial palp with 0, 5, 0, 4, 4 guard chaetae on papillae A‒E, respectively; lateral process of labial palp slightly thicker than normal chaetae, with tip beyond apex of labial papilla ( Fig. 9 ). Labial chaetae as mrel1l2, all smooth, ratio of r to m 0.6‒0.7; chaetae X, X2 and X4 ciliate; chaeta X3 usually smooth but ciliate on one side of one specimen. Chaetae along cephalic groove 8‒9, four of them smooth ( Fig. 10 ).

Trochanteral organ with 22–31 smooth spiny chaetae; 10–15 in arms and 11‒16 between them ( Fig. 11 ). Partial inner differentiated tibiotarsal chaetae “smooth” with ciliations closely appressed to axis. Tibiotarsi distally with 10 chaetae in a whorl. Unguis with 3 inner teeth; 2 paired teeth unequal, outer one large; distal unpaired tooth minute. Unguiculus truncate or swollen with a large outer tooth. All tenent hairs smooth and pointed ( Figs 12–14 ). Abd. IV 5.6‒5.7 times as long as Abd. III along dorsal midline. Ventral tube anteriorly with at least 3+3 ciliate large chaetae; posteriorly with 4 apical smooth and about 20 proximal ciliate chaetae ( Fig. 15 ); each lateral flap with 8 smooth chaetae ( Fig. 16 ). Manubrial smooth chaetae unclear. Distal part of manubrium ventrally with 6+6 ciliate chaetae ( Fig. 17 ). Manubrial plaque with 3 (rarely 2) pseudopores and 3 (rarely 4) ciliate chaetae ( Fig. 18 ). Distal smooth part of dens 0.7 times as long as mucro. Mucro bidentate with apical tooth larger than basal one; basal spine long with tip nearly reaching apical tooth ( Fig. 19 ).

Th. II with 3(4) (m1, m2, m 2i) medio-medial, 3(2) (m4, m 4i, m4p) medio-lateral, 21‒23 posterior mac, 1 ms and 2 sens; ms inner to sens; m 1i present on one side in a specimen; mac m 4i rarely absent. Th. III with 3 0‒31 mac and 2 lateral sens; m 5i and a 6i as mac ( Fig. 20 ). Abd. I with 8(7) (a2, a3, m2–4, m 2i, m 4i, m4p) mac, 1 ms and 1 sens; sens inner to ms; a2 as mac in one specimen and mic in another specimen; mac m 4i rarely absent. Abd. II with 3 (m3, m3e, m3ep) central, 1 (m5) lateral mac and 2 sens. Abd. III with 1 (m3) central, 3 (am6, pm6, p6) lateral mac and 2 sens; ms absent ( Fig. 21 ). Abd. IV with 6 central (I, M, B4, B5, A5, A6) and 6 lateral mac (D3, E2–4, E2p, F1) ( Fig. 22 ); two sens (as, ps) of normal length and others elongate (not represented). Abd. V with 3 sens ( Fig. 23 ).

Ecology. In aphotic zone of cave.

Etymology. Named after Miss Liu, who helped to collect the animals.

Remarks. Sinella liuae sp. nov. is characterized by presence of small chaetae X and X2‒4 posterior to labium, 6+6 central mac on Abd. IV, and truncate unguiculus. It is closest to S. sineocula in claw structure, “smooth” inner differentiated tibiotarsal chaetae, long mucronal spine, ciliate post-labial chaetae X, X2 and X4, and chaetotaxy of Abd. I‒Abd. III, but differs from the latter in pointed tenent hairs and 6+6 central mac on Abd. IV ( Table 1 ).

Figures

FIGURES 1 – 3. Habitus: 1, Sinella liuae sp. nov.; 2, Sinella hunanica sp. nov.; 3, Sinella tiani sp. nov.

FIGURES 4 – 11. Sinella liuae sp. nov.: 4, Ant. III organ; 5, distal part of Ant. IV, ventral view; 6, clypeal chaetae; 7, dorsal cephalic chaetotaxy; 8, maxillary outer lobe; 9, lateral process of labial palp; 10, labial and post-labial chaetae, arrow indicating the chaeta may be absent; 11, trochanteral organ.

FIGURES 12 – 20. Sinella liuae sp. nov.: 12, fore claw; 13, middle claw; 14, hind claw; 15, posterior face of ventral tube; 16, lateral flap of ventral tube; 17, distal part of manubrium ventrally; 18, manubrial plaque; 19, mucro; 20, thoracic chaetotaxy.

FIGURES 21 – 23. Abdominal chaetotaxy in Sinella liuae sp. nov.: 21, Abd. I – III; 22, Abd. IV; 23, Abd. V.