Coecobrya polychaeta Zhang & Nilsai

Nilsai, Areeruk, Jantarit, Sopark, Satasook, Chutamas & Zhang, Feng, 2017, Three new species of Coecobrya (Collembola: Entomobryidae) from caves in the Thai Peninsula, Zootaxa 4286 (2), pp. 187-202 : 195

Coecobrya polychaeta Zhang & Nilsai sp. nov.

Figs 3 , 25–40 , Tables 2–3

Types. Holotype: female on slide, Thailand: Satun Province: Mueang District: Phraya Bangsa cave, 6.77541°N, 100.04161°E, altitude 23 m, 4.x.2016, S. Jantarit and A. Nilsai leg. (collection #THA_SJ_STN08) . Paratypes: one male and three females on slides and 24 in alcohol, same data as holotype . Two paratypes on slides and four in alcohol deposited in NJAU and others in PSU-NHM.

Description. Body length up to 2.58 mm. Body whitish in alcohol ( Fig. 3 ).

Antennae 5.91–7.12 times as long as cephalic diagonal. Antennal segment ratio as I: II: III: IV = 1: 1.52–1.76: 1.78–2.10: 2.78–4.62. Smooth spiny mic at base of antennae: 3(4) dorsal, 3(2) ventral on Ant. I, one internal, one external and one ventral on Ant. II. Long smooth straight chaetae absent on antennae. Distal Ant. II with one paddle-like S-chaeta. Ant. III organ not clearly seen.

Eyes absent. Prelabral and labral chaetae 4/5, 5, 4, all smooth; three median chaetae of the first and the second rows longer than lateral ones ( Fig. 25 ). Clypeus with five long, smooth and 7–10 short, ciliate chaetae ( Fig. 26 ). Dorsal cephalic chaetotaxy with four antennal (An), three median (M) and eight sutural (S) mac; Gr. II with three mac; A0 as mic ( Fig. 27 ). Mandibles with 4+5 (4 left, 5 right) large apical teeth. Four smooth sublobal hairs on maxillary outer lobe ( Fig. 28 ). Lateral process of labial palp very long and as thick as normal chaetae ( Fig. 29 ). Labial chaetae as M 1m 2rel1l2; M1 only smooth in one side of one specimen; r minute. Postlabial chaeta X smooth; chaeta X2 smooth and minute; chaeta X4 ciliate and minute. Cephalic groove with 6–7 smooth and 5–10 ciliate chaetae ( Fig. 30 ).

Trochanteral organ with 15–25 smooth spine-like chaetae; 6–9 in arms and 9–16 between them ( Fig. 31 ). Partial inner differentiated tibiotarsal chaetae finely ciliate with ciliations not closely appressed to axis. Unguis with three inner teeth; two paired teeth subequal. Unguiculus basally swollen with an inner tooth and a serrate outer edge. Tenent hairs pointed ( Fig. 32 ). Abd. IV 3.90–4.62 times as long as Abd. III along dorsal midline. Ventral tube anteriorly with 12 ciliate chaetae on each side and two of them much larger ( Fig. 33 ); posteriorly with 20–31 chaetae, at least six of them smooth; each lateral flap with 9–12 smooth chaetae ( Fig. 34 ). Furcula without smooth chaetae. Distal part of manubrium ventrally with 15–25 ciliate chaetae on each side ( Fig. 35 ). Manubrial plaque with two pseudopores and 4–10 ciliate chaetae ( Fig. 36 ). Distal smooth part of dens 0.72–0.85 times as long as mucro. Mucro falcate with a long basal spine, nearly reaching the tip of the apical tooth ( Fig. 37 ).

Th. II with 7(6) (m1, m 1i, m 1i 2, m2, m 2i, m 2i 2, m 2i 3) medio-medial, three (m4, m 4i, m4p) medio-sublateral and 29–40 posterior mac; ms inner to sens. Th. III with 35–43 mac; a1a as mac ( Fig. 38 , Table 2). Abd. I with 89 (a2–3, a5, m2–4, m 2i, m4p, p5) mac; mac p5 rarely present. Abd. II with 4(3) (a2, m3, m3e, m3ep) central and one (m5) lateral mac; mac m3ep absent in one side of one specimen. Abd. III with one (m3) central and three (am6, pm6, p6) lateral mac; Abd. IV with six central (I, M, B4–5, A5–6) and nine (D3, E2–4, E2p, F1–3, F3a) lateral mac ( Fig. 39 ). S-chaetae formula: 2+ms, 2/1+ms, 2, 2+ms, =21, 3; as and ps on Abd. IV 1 /4 length of others ( Figs 38–40 ).

GenBank number. KY704921 – KY704926 .

Ecology. This species was indigenous to the small chamber in the dark zone on surface of muddy ground in a humid environment. Bat guano was absent in this area.

Etymology. Name after the abundant chaetae on ventral tube and both sides of distal part of manubrium.

Remarks. Coecobrya polychaeta sp. nov. can be separated from other Coecobrya species by the combination of large size, extremely long antennae and long lateral process of labial palp, four sublobal hairs on maxillary outer lobe, A0 as mic on dorsal head, labial chaetae M 1m 2rel1l2, minute postlabial chaetae X2 smooth and X4 ciliate, paired teeth subequal on unguis, serrate outer edge on unguiculus, abundant chaetae on ventral tube and both sides of distal part of manubrium, 7(6) medio-medial mac on Th. II, four antero-medial mac on Th. III, 8(9) mac on Abd. I, four central mac on Abd. II, six central and nine lateral mac on Abd. IV, and presence of ms on Abd. III. Antennae of the new species, as those in Coecobrya nupa Christiansen & Bellinger, 1992 , are the longest one in the genus. Elongated lateral process of labial palp and four sublobal hairs on maxillary outer lobe are also observed for the first time within the genus. Additional differences from closely related species are included in Table 3; it can be distinguished from them by mic A0 and 3+3 Gr. II mac on dorsal head, ciliate labial chaeta M1, four sublobal hairs on maxillary outer lobe, long lateral process of labial palp, 8–9 mac on Abd. I, and 4(3) central mac on Abd. II.

Figures

FIGURES 2 – 5. Habitus: 2, Coecobrya chumphonensis sp. nov.: 3, Coecobrya polychaeta sp. nov.; 4, Coecobrya cf. polychaeta sp. nov.; 5, Coecobrya cavicta sp. nov. Scale bar: 1 mm.

FIGURES 25 – 37. Coecobrya polychaeta sp. nov. 25, labrum; 26, clypeal chaetae; 27, dorsal cephalic chaetotaxy; 28, maxillary outer lobe; 29, lateral process of labial palp; 30, labial and postlabial chaetae; 31, trochanteral organ; 32, hind Claw; 33, anterior face of ventral tube; 34, posterior face and lateral flap of ventral tube; 35, distal part of manubrium ventrally; 36, manubrial plaque; 37, mucro.

FIGURES 38 – 42. Tergal chaetotaxy: 38 – 40 for Coecobrya polychaeta sp. nov. and 41 – 42 for Coecobrya cf. polychaeta sp. nov. 38, Th. II – III; 39, Abd. I – IV; 40, Abd. V; 41, Abd I; 42, central mac on Abd. II.