Dicranocentrus liuae, Xu, Guo-Liang & Zhang, Feng, 2014

Xu, Guo-Liang & Zhang, Feng, 2014, A new species of Dicranocentrus (Collembola, Entomobryidae) from China with comments on the systematic position of the genus, ZooKeys 417, pp. 1-8 : 3-5

Taxon classification Animalia Entomobryomorpha Entomobryidae

Dicranocentrus liuae sp. n. Figs 2-14, Table 1

Type locality.

China, Anhui, Shitai, Guniujiang, 30.092°N, 117.482°E, altitude 208m.

Material.

Holotype: ♀ on slide, China, Anhui, Shitai, Guniujiang, the entrance of Yan hamlet, 30.092°N, 117.482°E, altitude 208m,15 August 2011, F Zhang, DY Yu and YH Ren leg. (#C9676). Paratypes: 3 ♀♀ and 1 ♂ on slides, 4 in alcohol, same data as holotype. Other material: 1 ♀ on slide, China, Anhui, Shitai, Gongxi, 27 August 1994, JX Chen leg. (#C8391); 1 ♀ on slide, China, Zhejing, Jin Xian, Tiantongshan National Natural Reserve, 10 June 1995, JX Chen leg. (#C8458).

Description.

Body length up to 1.8 mm.

Ground colour pale yellow. Eye patches dark. Blue pigment present on antennae and legs (Fig. 2). Scales brown, rounded, truncate, or pointed with numerous short striations; scales present on Ant. I‒IV, body, legs, both side of ventral tube and manubrium, and ventral side of dens.w

Antenna 2.0-2.7 times as long as cephalic diagonal. Ant. V and VI annulated and their length ratio as 1.2-0.7: 1. Four types of common chaetae observed: ciliate, thin (Fig. 3A) or thick (Fig. 3B) mic; smooth, straight, spiny mic on Ant. I and III (Fig. 3C); long, straight chaetae smooth or weakly ciliate (Fig. 3D). Most S-chaetae slightly curved, short (Fig. 3 E–I) or long (Fig. 3J). Distal Ant. II with 1 rod-like S-chaeta ventrally (Fig. 3K), 2 strongly curved, thickened S-chaetae externally (Fig. 3 L–M). Ant. VI apical bulb absent.

Eyes 8+8, G and H smaller. Prelabral and labral chaetae 4/5, 5, 4, all smooth; prelabral ones stronger than labral ones. Labral papillae 4, cone-like with apical spine often curved (Fig. 4). Mandibles with 4+5 apical teeth. Lateral process of labial palp papillae E as thick as normal chaetae, with tip not reaching apex of labial papilla. Subapical chaeta of maxillary outer lobe thicker than apical; 3 smooth sublobal hairs on maxillary outer lobe. Labium with 5 smooth proximal chaetae and 8-10 submentum chaetae; the most external one A5 on mentum shorter than A1‒5; at most 1 ciliate chaeta on submentum (Fig. 5). PLQ chaetae smooth and 2+2 weakly ciliate chaetae posterior to PLQ. Dorsal cephalic chaetotaxy with10-13 antennal (An), 3 median (M), sutural S0-7, 1 postocular (P0) and 9 posterior (P) mac. Interocular chaetae 3 as p, s, t (Fig. 6).

Trochanteral organ with about 30 smooth spiny chaetae (Fig. 7). Some inner differentiated tibiotarsal chaetae smooth under light microscope. Unguis with 3 inner teeth, all minute. Unguiculus lanceolate with outer edge smooth. Tenent hairs acuminate (Fig. 8).

Abd. IV 1.66-1.89 times as long as Abd. III along dorsal midline. Ventral tube anteriorly with many weakly ciliate chaetae and some scales (Fig. 9); posteriorly with many smooth chaetae; both sides with scales; each lateral flap with about 20 smooth chaetae (Fig. 10). Tenaculum with 4+4 teeth, corpus with 2-4 smooth chaetae. Manubrial plaque with 3 pseudopores and 5-9 ciliate chaetae on each side (Fig. 11). Manubrium dorsally with rows of smooth chaetae but their number not clear. Dens without inner spines. Dental of lobe with 1+1 large blunt ciliate and about 5+5 small smooth chaetae. Smooth distal part of dens 4.4-5.7 times as long as mucro; mucro bidentate with two subequal teeth (Fig. 12).

Th. II with 2 inner and 2 outer mac on medial area, 9 posterior mac, 1 ms and 2 sens; anterior ms external to sens. Th. III with 15-16 mac and 2 lateral sens (Fig. 13). Abd. I with 3 mac, 1 ms and 1 sens; ms external to sens. Abd. II with 2 inner, 1 lateral mac and 3 sens. Abd. III with 1 inner, 2 lateral mac, 1 ms and 3 sens. Abd. IV with 3-5 inner, 10 lateral mac, and many (number undetermined) elongate sens. Abd. V with 4 sens (Fig. 14).

Etymology.

Named after the former member Ms L. Liu in our lab, who initiated the study of the genus in China.

Ecology.

In litter or on leaves of forest floor.

Remarks.

This new species belongs to sundanensis-group according to Mari-Mutt(1979). It is the only member with 1+1 inner mac on Abd. III in sundanensis-group. It is most similar to Dicranocentrus wangi in labrum, cephalic chaetotaxy, trochanteral organ, tergal chaetotaxy of thorax and Abd. I–II, ventral tube, and claw structure. It differs from the latter in having a shorter Ant. V, 9 posterior cephalic mac, 1+1 inner mac on Abd. III, 2-4 chaetae on tenaculum, and the absence of dental spines (Table 1). S-chaetotaxy is also described in the genus for the first time: ms 1, 0|1, 0, 1, 0, 0 and sens 2, 2|1, 3, 3,?, 4.