Homidia obliquistria, Ma, Yi-Tong & Pan, Zhi-Xiang, 2017

Ma, Yi-Tong & Pan, Zhi-Xiang, 2017, Two new species of Homidia (Collembola: Entomobryidae) from Southwestern China, Zootaxa 4290 (3), pp. 519-530 : 525-528

Homidia obliquistria sp. nov.

Figs 5 ̄6, 29̄48

Types. Holotype: ♀ on slide, Qianlingshan Park , Guiyang City, Guizhou Province, CHINA, Qian-sheng Sun leg. (#1128) . Paratypes: Three ♀ on slides, same data as holotype. All deposited in NTU.

Description. Body length up to 3.1 mm.

Ground colour pale yellow in alcohol. Distally Ant. I black and gradually darker from Ant. IĪIV. Eye patches dark blue, narrow black band present between anterior eyes. Th. IĪIII with three dark narrow longitudinal stripes, two laterally and one centrally. Tip of femur and tibiotarsus of legs with scattered black pigment. Abd. ĪIII laterally with oblique dark stripes from anterior to posterior, posterior margins with very narrow bands. Abd. III with a pair of central dark patches. Abd. IV with medial and posterior two transverse brown to dark bands extending more anteriorly on both sides, pair of black patches present laterally between them. Abd. V with posterior half pigmented black ( Figs 5–6 ). Ventral side of body unpigmented.

Antenna about 2.7 times cephalic diagonal, 0.51 times body in length, antennal segment ratio as I:II:III:IV = 1:1.3:1.0:1.7 (based on one individual). Ant. I with 3 dorsal, 4 ventral basal spiny smooth chaetae ( Fig. 29 ). Apical bulb of Ant. IV bilobed ( Fig. 30 ). Eyes 8+8, G and H smaller than others, interocular chaetae p, r, t present. Dorsal cephalic chaetotaxy with 3 antennal (A), 3 ocellar (O) and 6 sutural (S) mac, Gr. II with 6̄7 mac ( Fig. 31 ). Prelabral and labral chaetae as 4/5, 5, 4, all smooth ( Fig. 32 ). Maxillary outer lobe with 1 apical chaeta, 1 subapical chaeta and 3 sublobal hairs on sublobal plate; subapical chaeta slightly longer than apical one ( Fig. 33 ). Lateral process (l.p.) of labial papilla E differentiated, as thick as normal chaeta with tip not reaching apex of papilla E ( Fig. 34 ), labial palp not clear seen. Setal formula of labial base as M1M2ReL1L2, chaeta e smooth, others ciliate; chaetae G1‾4, H2‾3, X and X3 on posterior labium slightly expanded, H1 sometimes slightly expanded, morphology of chaeta H4 unclear, X4 not seen ( Fig. 35 ).

Complete sens and ms on Th. IĪAbd. III as 22|122(about 25)3 and 10|1 0 100. Th. II with 4 medio-medial (m1, m2, m 2i, m 2i 2), 3 medio-sublateral (m4, m 4i, m4p), about 40 posterior mac and p6 as mac. Th. III with 49̄56 mac and p4̄6 as mac ( Fig. 36 ). Pseudopores on coxa ĪIII as 2, 3, 2 respectively, coxal macrochaetal formula as 3/4+1, 3/4+2 ( Fig. 37 ). Trochanteral organ with 53̄64 smooth spiny chaetae ( Fig. 38 ). Partial inner differentiated tibiotarsal chaetae with ciliations closely appressed to axis; most distal smooth chaeta present on hind leg. Tenent hair capitate and subequal to inner edge of unguis in length. Unguis with 3 inner and 2 lateral teeth. Unguiculus lanceolate with outer edge slightly serrate and basal tooth larger ( Fig. 39 ).

Abd. I with 11¯12 (a1¯3, a5, a1a, m2¯4, m 2i, m 4i, m4p and a5; a 5i sometimes as mac) mac and 2 S-chaetae (ms antero-external to sens). Abd. II with 6 (a2, a3, m3, m3e, m3ea, m3ep) central, 1 (m5) lateral mac, and 2 Schaetae. Abd. III with 2 (a2, m3) central and 4 (am6, pm6, m7a, p6) lateral mac, and 3 S-chaetae ( Fig. 40 ). Abd. IV with about 25 S-chaetae, 15¯24 mac on anterior part and irregularly arranged in a transverse row; posterior part with 9¯10 (A4¯6, B4¯6, Ae4¯7; Ae5 sometimes as mic) mac and 19¯22 mes ( Fig. 41 ) or 4¯5 mes ( Fig. 42 ); laterally with about 30 mac ( Figs 41–42 ). Anterior face of ventral tube with 37̄45 ciliate chaetae, including 3+3 mac, line connecting proximal (Pr) and external-distal (Ed) mac oblique to median furrow ( Fig. 43 ); posterior face with many ciliate chaetae in different size and about 6 smooth subapical chaetae ( Fig. 44 ); lateral flap with 7 smooth and 21̄28 ciliate chaetae ( Fig. 45 ). Tenaculum with 4+4 teeth and 1 large, multilaterally ciliate basal chaeta ( Fig. 46 ). Manubrial plaque with 3 pseudopores, 2 inner and 11̄12 outer ciliate chaetae ( Fig. 47 ). Dens with about 70 spines on inner side. Mucro bidentate with subapical tooth conspiculously larger than apical one; basal spine short, with tip only reaching apex of subapical tooth ( Fig 48 ).

Ecology. Found in decomposing leaf litter.

Etymology. Specific epithet name is refers to the oblique stripes present on lateral sides of Abd. ĪIII (Latin obliqui + strita).

Remarks. The new species is characterised by colour pattern, M2 present on labium, slightly expanded chaetae on posterior labium and numerous mac and mes on Abd. IV. It is the most similar to H. polyseta in colour pattern, mac and mes on central Abd. IV and dorsal chaetotaxy of Th. IĪAbd. III. However, it can be discriminated from the latter by labial basal chaetae, medio-medial mac on Th. II, mac on Abd. I and narrow black bands on lateral side of Abd. ĪIII. This new species is also similar to H. latifolia in colour pattern and expanded chaetae on labium, but it can be distinguished from the latter by many mac and mes on central Abd. IV and narrow black bands on lateral side of Abd. ĪIII. The detailed differences between them are listed in Table 3.

The present study was supported by the National Natural Science Foundation of China (31601880) and Zhejiang Provincial Natural Science Foundation of China (LQ14C040002). Thanks are given to Dr. F. Zhang (Nanjing Agricultural University) and anonymous referees who provided advice on this manuscript and greatly improved it.

Figures

FIGURES 1 – 6. Habitus: 1 ̅ 4, Homidia nigrifascia sp. nov.; 5 ̅ 6, Homidia obliquistria sp. nov.

FIGURES 29 – 39. Homidia obliquistria sp. nov. 29, basal Ant. I; 30, apex of Ant. IV; 31, cephalic chaetotaxy; 32, prelabral and labral chaetae; 33, maxillary outer lobe; 34, labial papilla E; 35, labial and posterior labial chaetae; 36, chaetotaxy of Th. II ̅ III; 37, coxal macrochaetal formula: A, fore leg; B, mid leg; C, hind leg; 38, trochanteral organ; 39, distal tibiotarsus and claw complex of hind leg.

FIGURES 40 – 48. Homidia obliquistria sp. nov. 40, chaetotaxy of Abd. I ̅ III; 41 ̅ 42, chaetotaxy of Abd IV; 43, anterior face of ventral tube; 44, posterior face of ventral tube; 45, lateral flap of ventral tube; 46, tenaculum; 47, manubrial plaque; 48, mucro.