Homidia yandangensis, Pan, Zhi-Xiang, 2015

Pan, Zhi-Xiang, 2015, Two new species of Homidia (Collembola, Entomobryidae) and a key to species in the genus from Zhejiang Province, China, Zootaxa 4034 (3), pp. 515-530 : 516-523

Homidia yandangensis sp. nov.

Figs 1–29, Table 1

Holotype. 1 ♀ on slide, China, Zhejiang Province, Wenzhou City, Yueqing, Caijialin village 28 ° 25 '53.10"N, 121 °0'42.04"E, elev. 151 ± 3 m, sample number S 4448, 16.I. 2015, Z-X Pan, Y-H Pan and C-C Si.

Paratypes. 2 ♀ adult and 1 subadult (instar uncertain) on slides and 3 adults in ethanol, same data as holotype. All types deposited in the School of Life Sciences, Taizhou University, Zhejiang Province, P. R. China (TZU).

Additional examined specimens: 2 ♀ on slides, China, Zhejiang Province, Taizhou City, Wenlin, Daxi Town, Huwulin. 28 ° 26 '35.24"N, 121 ° 13 '56.13"E, elev. 111 ± 3 m, sample number S 4446, 16.I. 2015, Z-X Pan, Y-H Pan and C-C Si. All deposited in TZU.

Etymology. Named after the Yandang Mountain, the collection locality.

Adult. Body length up to 2.67 mm.

Ground colour pale white in ethanol. Dorsal body and legs with brown pigment, darker on front of head and becoming gradually darker from thorax to abdomen. Eye patches dark blue, with a posterior V-shape unpigmented patch between them. Postero-lateral head scattered with brown pigment. Antennae gradually becoming darker from Ant. I to Ant. IV. A divided dark stripe medially on thorax and gradually becoming wider from Th. II to Th. III. Anterior Abd. IV with irregular unpigmented spots ( Fig. 1). Ventral side of body white except for brown pigment distally on VT ( Fig. 2).

Eyes 8 + 8, G and H smaller than others and difficult to observe under light microscope; eye patch with 3 chaetae, p largest ( Fig. 4). Antennal length 1.49–1.89 times the cephalic diagonal; antennal segments ratio as I: II: III: IV = 1: 1.19–1.89: 1.26–1.52: 2.22–3.14. Ant. I with 3 dorsal, 4 ventral basal smooth mic ( Fig. 5); Ant. II with 5 basal smooth mic ( Fig. 6), and 2–4 (2–3 longer and 0–1 shorter) distal rod-like S-chaetae ( Fig. 7). Ant. III organ with 2 rod-like and 3 short guard S-chaetae ( Fig. 8). Apical bulb of Ant. IV bilobed ( Fig. 9). Dorsal cephalic chaetotaxy with 3 antennal (A), 3 ocellar ( O) and 5 sutural (S) mac, Gr. II with 5 mac ( Fig. 4). Prelabral and labral chaetae as 4 / 5, 5, 4, all smooth; labral papillae absent, intrusion U-shaped ( Fig. 10). Chaetal formula of labial base as MRel 1 L 2, e and l 1 smooth and others ciliate ( Fig. 11); posterior labial chaetae not expanded. Five papillae A–E on labial palp with 0, 5, 0, 4, 4 guard chaetae, respectively. Lateral process (l.p.) thin with tip reaching apex of papilla E ( Fig. 12). Maxillary outer lobe with 1 apical, 1 subapical chaetae and 3 sublobal hairs on sublobal plate, subapical chaeta slightly larger than apical one ( Fig. 13). Mandible with 4 / 5 (left/right side) teeth.

Complete body sens as 22 / 122 (about 46) 3, ms as 10 / 10100. Th. II with 4 (m 1, m 2, m 2 i and m 2 i 2) mediomedial, 3 (m 4, m 4 i and m 4 p) medio-sublateral and 3 S-chaetae (ms antero-internal to sens); posterior with 31–39 mac; p 4, p 4 i and p 5 as mac, p 6 as mic. Th. III with 37–42 mac and 2 sens; p 5 and p 6 as mac, p 4 as mic ( Fig. 14). Coxal macrochaetal formula as 3 (2 pseudopores)/ 4 + 1, 3 (3 pseudopores)/ 4 + 2 (2 pseudopores) ( Figs 15 a–c). Trochanteral organ with 37–45 smooth chaetae ( Fig. 16). Inner tibiotarsus with 2–3 lines weakly ciliated chaetae. Tenent hair capitate, subequal to inner edge of unguis. Unguis with 4 inner, 2 lateral and 1 outer teeth. Unguiculus lanceolate with outer edge weakly serrate, basal tooth larger than others ( Fig. 17).

Abd. IV length 6–7 times as Abd. III along dorsal axis. Abd. I with 9 (10) (a 2–3, a 5, m 2–4, m 2 i, m 4 i and m 4 p; a 1 sometimes present) mac and 2 S-chaetae (ms antero-internal to sens). Abd. II with 6 (a 2, a 3, m 3, m 3 e, m 3 ea and m 3 ep) central and 1 (m 5) lateral mac. Abd. III with 2 (a 2 and m 3) central and 4 (am 6, pm 6, p 6 and m 7 a) lateral mac ( Fig. 14). Abd. IV with about 44 elongate and 2 normal sens; area A 7 with 7–10 mac arranged in irregular transverse row; areas A 8–10 with 2 - 1 (2)- 3 mac (A 4, A 6, Ae 7, B 4–6; A 5 only present in individuals from Huwulin). Abd. V with 3 sens, middle one external to m 3; m 3 a, and a 5 a as mac, a 1, and p0 as mic ( Fig. 18). Posterior face of VT with 5 (2 + 1 + 2) subapical smooth chaetae, middle one shorter ( Fig. 20), one individual from Huwulin with 7 chaetae (3 shorter between 4 longer) ( Fig. 19); each lateral flap with 7–8 smooth and 7–10 ciliate chaetae on each side; anterior face with many ciliate chaetae, 3 + 3 of them as mac, line connecting proximal (Pr) and external-distal (Ed) mac parallel to median furrow ( Fig. 20). Manubrial plaque with 3 pseudopores and 6–11 ciliate chaetae ( Fig. 21). Dens with about 35 inner spines; basal chaetae (bs 1 and bs 2) spiniform, bs 1 shorter than bs 2; chaeta pi slender and longer than bs ( Fig. 22). Mucro bidentate with subapical tooth larger than apical one; basal spine short, with tip reaching just beyond subapical tooth; distal smooth part of dens subequal to mucro in length ( Fig. 23). Tenaculum with 4 + 4 teeth and 1 large, basal, multi-laterally ciliate chaeta ( Fig. 24).

Subadult. Juveniles with similar colour pattern to adult, however, the pigment on dorsal body pale brown, and central stripe on Th. II–III narrower than adult ( Fig. 3). Dorsal mac chaetotaxy given in Figs 25–26. Chaetae a 1 on Abd. I and a 2 on Abd. III as mic. Abd. IV with chaetae A 6, B 6 and Ae 7 as mesochaetae, elongate sens on posterior margin longer than adult. Chaetae a 1, a 3 and a 5 on Abd. V as mic. Others dorsal chaetotaxy as in adult. Relative position of ms/sens on Abd. I and middle sens/m 3 on Abd. V same as adult. Posterior face of VT with 4 subapical smooth chaetae (without medial shorter one which present on adult) ( Fig. 27). Manubrial plaque with 2 pseudopores ( Fig. 28).

Ecology. Specimens from Caijialin were found in leaf litter of Eriobotrya japonica (Thunb.) and Myrica rubra (Lour.) , and individuals from Huwulin were found in leaf litter of Liquidambar formosana (Hance) .

Remarks. The new species is characterised by central dark stripe on Th. II–III and brown pigment scattered on dorsal body, ms antero-internal to sens on Abd. I and median sens external to m 3 on Abd. V, 6 or 7 mac on posterior central Abd. IV. Juveniles can be diagnosed by a stripe centrally Th. II–III, mac and mesochaetae on posterior central Abd. IV, relative position of ms/sens on lateral Abd. I and median sens/m 3 on Abd. V. However. The juveniles have fewer mac than in adult.

This species is most similar to H. zhangi in brown pigment scattered on body, chaetotaxy of head and Th. II– Abd. III, and chaetal formula of labium. However, it can be distinguished from H. zhangi by the dark stripe on Th. II–III (absent on H. zhangi ), 6 or 7 mac on posterior central Abd. IV (3 or 4 on H. zhangi ) and median sens external to mac m 3 on Abd. V (anterior on H. zhangi ). Also, this new species similar to H. fromosana in chaetotaxy on head, Th. II–Abd. II and Abd. IV; detailed differences between them are listed in Table 1.

The localities of the specimens examined from Caijialin and Huwulin are 22 kilometers apart in a straight-line. The morphological characters of the specimens from two localities agreed well except for area A 9 of Abd. IV without mac A 5 of specimens from Caijialin (present in specimens from Huwulin) and 5 subapical smooth chaetae on posterior face of VT of specimens from Caijialin (one individual from Huwulin with 7 and other one with 5). Because of the lack of other morphological differences, they are considered to be same species as the new species described here.

characters H. yandangensis sp. nov. H. zhangi H. formosana Colour pattern

Ground colour pale white pale white yollow brown

Dark stripe on medial Th. II–III present absent absent

Pigment in front of eye patches band spot spot

Pigment between eye patches black absent absent

Dark bands on Abd. IV–V absent absent present Labial chaeta l.p. compared with a apex of papilla E reaching not reaching reaching Inner teeth of unguis 4 4 3 Macrochaetae on Abd. I 9 (10) 10–11 9 Relative position of ms/sens on lateral Abd. I antero-internal antero-internal anterior Macrochaeta a 1 on Abd. I sometimes present absent present Macrochaetae on areas A 8–10 of Abd. IV

A 4 present absent present

B 4 and B 5 present absent present Chaeta a 1 on Abd. V mic mac mac Relative position of ms/m 3 on Abd. V external anterior postero-external Ventral tube

Line connecting Pr and Ed mac to median furrow parallel oblique oblique

Smooth chaetae on posterior face 5 (rarely 7) 4 5

Smooth chaetae on one side of lateral flap 7–8 4–6 6–7

Ciliate chaetae on one side of lateral flap 7–10 13–23 7–12