Homidia leniseta, Pan & Yang, 2019

Pan, Zhi-Xiang & Yang, Wan-Qin, 2019, Reports of two peculiar pigmented new species of genus Homidia (Collembola: Entomobyridae) from Southern China, with description of subadults chaetotaxy, Zootaxa 4671 (3), pp. 369-380 : 375-378

Homidia leniseta sp. nov.

Figs 33–66 , table 2

Type material. Holotype: female on slide, China, Guangdong Province, Guangzhou City, Tianhe District, Long- dong Reservoir , 23.235566N 113.399017E, alt. 127± 5 m, sample number 4661, 25.III.2018, collected by Z-X Pan and S-S Zhang.

Paratypes. Five female adults and one subadult (maybe the second instar) on slide, two in ethanol. Same date as holotype. All types deposited in TZU .

Etymology. Named after the smooth chaetae l 2, g 1-4 and h 1-3 present on labium (latin: “lenis”, smooth, “seta”, chaetae).

Description. Adults. Size. Body length up to 2.18 mm. Colour pattern. Ground colour pale yellow. eye patches dark blue. Antennae pale, without dark pigment. Postero-central margins of Th. II–III and Abd. IV with M-shaped dark patches. Lateral side of Th. II–Abd. II and posterior margin of Abd. V slight pigmented. Abd. III mostly dark pigment, except lateral side with small unpigmented patch. Coxae, VT, furcula and ventral side of body without pigment ( Figs 33–35 ).

Head. Eyes 8+8, G and H smaller than others; eye patches with three chaetae ( Fig. 39 ). Antennal length 1.42– 1.71 times as long as head; antennal segment ratio as I: II: III: IV=1: 1.43–1.84: 1.21–1.34: 2.42–2.89. Basal part of Ant. I with three dorsal four ventral smooth mic ( Fig. 40 ), Ant. II with five basal smooth mic ( Fig. 41 ), five distal rod-like S-chaetae ( Fig. 42 ). Ant. III organ with two rod-like and three short guard S-chaetae. Apical bulb of Ant. IV bilobed ( Fig. 43 ). Dorsal cephalic chaetotaxy with three A, three O and five S mac, Gr. II with five mac ( Fig. 39 ). Clypeus with 13 chaetae, arranged in four lines (3/4/4/2) ( Fig. 44 ). Prelabral and labral chaetae as 4/5, 5, 4, all smooth ( Fig. 45 ). Chaetotaxic formula of labial base as MRel 1 l 2, M and R ciliate and others smooth; postlabial chaetae not expanded with g 1–4, h 1–3 smooth (one examined individual with G 4 ciliate), H 4, X, X 2, X 3 and X 4 ciliate (one individual without X 3) ( Fig. 46 ). Five papillae A–E on labial palp with 0, 5, 0, 4, 4 guard chaetae, respectively; the tip of lateral process (l.p.) slight exceeding apex of papilla E; hypostoma with two guard chaetae; five proximal chaetae ( Fig. 47 ). Maxillary outer lobe with one apical, one subapical chaetae and three sublobal hairs on sublobal plate, subapical chaeta slightly larger than apical one ( Fig. 48 ).

Thorax. Complete body sens as 2, 2/1, 2, 2, (at least 29), 3, ms as 1, 0/1, 0, 1, 0, 0. Th. II with three centro-medial mac (m1, m2 and m 2i), three centro-sublateral mac (m4, m 4i and m4p) and three S-chaetae (ms antero-internal to sens); posterior part with 23–27 mac; p4, p 4i, p5 and p6 as mac. Th. III with 35–37 mac and two sens; a5 series only one chaeta; p5 and p6 as mac, p4 as mic ( Fig. 49 ). Coxal macrochaetal formula as 3 (pseudopores unclear)/4+1, 3 (two pseudopores)/ 4+2 (two pseudopores) ( Figs 50–52 ). Trochanteral organ with 27–38 smooth chaetae ( Fig. 53 ). Tenent hair clavate, slight shorter than inner edge of unguis in length; unguis with three inner, two lateral and one outer teeth; unguiculus lanceolate with one basal tiny tooth ( Fig. 54 ).

Abdomen. Abd. IV length 3.96–5.72 times as long as Abd. III. Abd. I with 11 mac (a1–3, a 1i, m2–4, m 2i, m 4i, m4p and a5) and two S-chaetae (ms antero-external to sens). Abd. II with six central mac (a2, a3, m3, m3e, m3ea and m3ep) and one lateral mac (m5); trichobothria chaetae shorter than mac ( Figs 37–38 ). Abd. III with one central mac (m3) and four lateral mac (am6, pm6, p6 and m7a) ( Fig. 49 ). Abd. IV with at least 36 elongate (present anterior to “eyebrow” mac) and two normal length sens; “eyebrow line” with 2+2 mac; posterior central with four mac (A5–6, B4–5). Abd. V with three sens, middle one postero-external to m3; a1 and a3 as mic ( Fig. 55 ). Posterior face of VT with four (2+2) apical smooth chaetae; lateral flap with 7–9 smooth and 7–14 ciliate chaetae on each side ( Fig. 56 ); anterior face with many ciliate chaetae, 3+3 of them as mac, line connecting mac proximal (Pr) and external-distal (Ed) parallel to median furrow ( Fig. 57 ). Tenaculum with 4+4 teeth and one large, multi-laterally basal ciliate chaeta ( Fig. 58 ). Manubrial plaque with 2 pseudopores and 5–8 ciliate chaetae ( Fig. 59 ). Dens with 10–15 spines, chaetae bs1 shorter than bs2, and pi slight longer than bs ( Fig. 60 ). Mucro bidentate with subapical tooth larger than apical one; basal spine short, with tip reaching subapical tooth; distal smooth part of dens slightly shorter than mucro in length ( Fig. 61 ).

Subadult. The examined specimen with well-developed trochanteral organ, ciliate chaetae on lateral flap of VT, and secondary chaetae on dorsal side of the body. So, this specimen is latter than the second instar larvae, but its exact instar is unclear.

Ground colour pale white. Colour pattern same with adults, significantly dark pigment on Th. II–III, Abd. III–V ( Fig. 36 ).

Chaetotaxy shown in Figs 62–66 . Abd. III with one (m3) central mac ( Fig. 62 ). Chaetae g 1–4, h 2 on postlabial base smooth; H 1, H 3 and H 4 ciliate; X and X 4 absent ( Fig. 64 ).

Ecology. Same as H. chroma sp. nov., they are found in same sample.

Remarks. This new species can easily distinguished from other known species of genus Homidia by its unique colour pattern, 2+2 mac in eyebrow and 4+4 mac on postero-central part of Abd. IV, short trichobothria and adult individuals with labial chaetae l 2, g 1–4 and h 1–3 smooth. It is mostly similar to Homidia sichuanensis Jia, Zhang & Jordana, 2010 in colour pattern (medial part of Th. II–III, whole Abd. III and posterior margin of Abd. IV with dark pigment), one medial mac on Abd. III. However, it can be distinguished from H. sichuanenis by the absence of longitudinal stripes behind each eye patch (along lateral borders of the head), smooth labial chaetae and 2+2 eyebrow-like mac. Also, this new species similar to Homidia quadriseta Pan, 2018 (in: Zhuo et al. 2018) in colour pattern and 2+2 eyebrow-like mac on anterior part of Abd. IV, but obviously differ from the latter in Th. II–III by central dark pigment and smooth labial chaetae present in new species. Detailed comparison between these similar species is listed in table 2.

Figures

FIGURES 33–38. Homidia leniseta sp. nov.: 33–36, colour pattern; 33, dorsal view; 34, ventral view; 35, lateral view; 36, lateral view of subadults; 37, Abd. II (shown short trichobothria), dorsal view; 38, Abd. I–II, dorsal view.

FIGURES 39–48. Adults Homidia leniseta sp. nov.: 39, cephalic chaetotaxy; 40, basal part of Ant. I; 41, smooth chaetae on basal Ant. II; 42, distal part of Ant. II; 43, apical bulb and distal part of Ant. IV; 44, clypeal chaetotaxy; 45, labium; 46, labrum; 47, labial palp; 48, maxillary outer lobe. Scale bar=50 μm. (39–41, 43–45, dorsal view; 42, 46, 47, dorsal view; 48, lateral view).

FIGURES 49–54. Adults Homidia leniseta sp. nov.: 49, chaetotaxy of Th. II–Abd. III tergites; 50–52, coxal macrochaetal formula; 50, fore leg; 51, mid leg; 52, hind leg; 53, trochanteral organ; 54, distal part of tibiotarsus and claw of hind leg. Scale bar=50 μm. (49, dorsal view; 50–54, lateral view).

FIGURES 55–61. Adults Homidia leniseta sp. nov.: 55, chaetotaxy of Abd. IV–V tergites; 56–57, ventral tube; 56, distal posterior face and lateral flap; 57, distal anterior face; 58, tenaculum; 59, manubrial plaque; 60, basal dens; 61, distal dens and mucro. Scale bar=50 μm, (55, 59–60, dorsal view; 56, 58, posterior view; 57, anterior view; 61, lateral view).

FIGURES 62–66. Subadults of Homidia leniseta sp. nov.: 62, chaetotaxy of Th. II–Abd. III; 63, chaetotaxy of Abd. IV–V tergites; 64, labial and postlabial chaetotaxy; 65, trochanteral organ; 66, ventral tube. Scale bar=50 μm,. (62–63, dorsal view; 64–65, ventral view; 66, lateral view).