Homidia socia Denis, 1929

Jing, Mei-dong & Ma, Yi-tong, 2022, Two new species and two new records of Homidia (Collembola, Entomobryidae) from China, ZooKeys 1135, pp. 181-212 : 181

Homidia socia Denis, 1929

Figs 76 , 77, 78 , 79 , 80 , 81-86

Homidia socia Denis, 1929: 310.

Examined specimens.

3♀ on slides, China, Jiangxi Province, Nanchang City, Xinjian District, Jiuxi, 28°47'56"N, 115°45'11"E, 168 m asl, sample number 1243, collected by Y-T Ma, 12-XI-2020.

Description.

Size. Body length up to 2.16 mm.

Colouration. Ground ground colour pale yellow. Ant. I-IV with scattered blue pigment. Eye patches dark blue. A pair of longitudinal blue stripes present along lateral side of head to Abd. III. Medial longitudinal narrow stripe present from Th. II to Abd. III. Abd. V with blue pigment (Fig. 76 ).

Head. Antenna 0.52-0.66 × body length; antennal segment ratio I: II: III: IV = 1: 1.28-1.40: 1.00-1.20: 1.67-2.11. Eyes 8 + 8, G and H smaller than others, interocular chaetae with p, r, and t. Dorsal cephalic chaetotaxy with three antennal (A), three ocellar (O) and five sutural (S) mac (Fig. 77 ). Chaetal formula of labial base as MREL1L2, all ciliate, R/M as 0.67-0.72.

Thorax. Th. II with four medio-medial (m1, m2, m2i, m2i2), three medio-sublateral (m4, m4i, m4p), 30-33 (24) posterior mac. Th. III with 41-45 mac and two sens (Fig. 78 ). Pseudopores on coxa I-III as 2, 3, 2, respectively; coxal macrochaetal formula as 3/4+3, 3/4+2. Trochanteral organ with 39 smooth chaetae. Tenent hairs clavate and almost equal to inner edge of unguis. Unguis with four inner teeth, basal pair located at 0.38-0.45 distance from base of inner edge of unguis, distal unpaired teeth at 0.65-0.67 and 0.80-0.85 distance from base; unguiculus lanceolate, outer edge slightly serrate.

Abdomen. Range of Abd. IV length as 6.25-10.12 × as dorsal axial length of Abd. III. Abd. I with 10 (a2, a3, a5, a5i, m2-5, m2i, m4i, m4p) mac, ms antero-external to sens. Abd. II with six (a2, a3, m3, m3e, m3ea, m3ep) central, one (m5) lateral mac, and two sens. Abd. III with two or three (a2, m3, a3 sometimes absent) central and four (am6, pm6, m7a, p6) lateral mac, one ms, and two sens (Fig. 79 ). Abd. IV anteriorly with eight or nine mac arranged in irregular transverse row, A2 always present and anterior to transverse row; posteriorly with 6-10 central mac; laterally with 18-22 mac (Fig. 80 ). Anterior face of ventral tube with 39 ciliate chaetae, 3+3 of them as mac, line connecting proximal (Pr) and external-distal (Ed) mac oblique to median furrow (Fig. 81 ); posterior face with two distal smooth and numerous ciliate chaetae; lateral flap with six smooth and 24 ciliate chaetae (Fig. 82 ). Manubrial plaque dorsally with 11-14 ciliate chaetae and three pseudopores (Fig. 83 ); ventrally with 26 ciliate chaetae on each side (Fig. 84 ). Dens with 15 smooth inner spines (Fig. 85 ). Mucro bidentate with subapical tooth larger than apical one; tip of basal spine reaching apex of subapical tooth; distal smooth section of dens shorter than mucro in length (Fig. 86 ).

Ecology.

In the litter of leaves of Phyllostachys edulis .

Remarks.

This species was first described from Fujian Province, China by Denis (1929), mainly based on its colour pattern with three longitudinal stripes on dorsal side. Yosii (1942), Stach (1965), Lee and Park (1989), and Chiristiansen and Bellinger (1980, 1992) reported it from Japan, Vietnam, Taiwan (China), and USA, respectively, and their descriptions were relatively simple. Jordana (2012) also reported it based on Vietnamese and Japanese specimens that corresponded in colour pattern to H. socia forma flava Yosii, 1953 from Japan. In this work, several characters not previously mentioned are added, such as the chaetotaxy of the head, ventral tube, and manubrial plaque. Differences exist between the specimens collected from Jiangxi Province and other authors’ previous descriptions that are listed in Table 4 . Our specimens, with 15 spines on dens, are similar to those examined by Jordana (2012) which had 14 spines. Up to 30 spines were given by Denis (1929) for the type specimens of large size from Fujian. These specimens or specimens from the type locality will therefore need to be redescribed to confirm the assignment of our specimens as well as those described by Jordana (2012) to H. socia .

Distribution.

Japan, USA, Vietnam, and China (Anhui, Fujian, Guangxi, Jiangsu, Jiangxi, Taiwan, Zhejiang).

Figures

Figure 76. Habitus of Homidia socia Scale bar: 500 μm.

Figure 79. Chaetotaxy of Abd. I-III of Homidia socia. Scale bar: 50 μm.

Figure 80. Chaetotaxy of Abd. IV of Homidia socia. Scale bar: 50 μm.

Figures 77, 78. Homidia socia 77 dorsal chaetotaxy of head 78 chaetotaxy of Th. II-III. Scale bars: 20 μm (77); 50 μm (78).

Figures 81 - 86. Homidia socia 81 anterior face of ventral tube 82 posterior face and lateral flap of ventral tube 83 manubrial plaque 84 ventro-apical part of manubrium 85 proximal section of dens (circles also representing spines) 86 mucro. Scale bars: 20 μm.