Coecobrya cavicola Nilsai & Zeppelini & Bellini & Lima & Jantarit 2022, sp. nov.
Creators: name: Nilsai, Areeruk
name: Zeppelini, Douglas
name: Bellini, Bruno C.
name: Lima, Estevam C. A.
name: Jantarit, Sopark
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Collembola
Entomobryomorpha
Entomobryidae
Coecobrya
Coecobrya cavicola

description: Coecobrya cavicola sp. nov. Nilsai, Zeppelini & Jantarit
Figs 1B, 6‒9, Table 1
Type material. Holotype: female on slide. Thailand, Phrae province, Long district, unnamed cave, altitude 181 m a.s.l., approximately 18.02°N 099.94°E. 16 May 2018 S. Jantarit, A. Nilsai, K. Sarakhamhaeng and K. Jantapaso leg. (sample # THA_SJ_ PRE01), dark zone of the cave, by entomological aspirator.
Paratypes: same data as holotype, four specimens (two females and two subadults on slides)
Additional material: same data as holotype, six specimens (in ethanol) deposited in NHM-PSU and six specimens (in ethanol) deposited in CRFS-UEPB.
Holotype and four paratypes on slides deposited in NHM-PSU.
Description. Habitus (Figs 1B, 6A). Medium sized Entomobryidae. Body length 1.3‒1.5 mm (holotype 1.3 mm). Eyes absent. Color: whitish in alcohol. Body slender, not bent nor humped at the level of Th. II., moderately long antennae, legs and furca. Th. II slightly larger than the Th. III; Abd. IV about 3.05‒3.93 times as long as the Abd. III along the dorsal midline.
Pseudopores (Figs 7A, 8A, D, 9A‒E). Pseudopores present as round flat disks, smaller than mac sockets (Fig. 7A), except for the coxae and manubrium where psp are as large as mac sockets. Pseudopores present on various parts of the body: antennae, head, tergites, coxae and manubrium. On antennae, psp located ventro-apically between the tip of antennal segments and the chaetae of the apical row, or just below the apical row of chaetae (two on Ant. I, 2‒3 on Ant. II, and three on Ant. III). On head, 1‒2 psp located externally on each peri-antennal area (Fig. 8A). On tergites, 1+1 psp close to the axis from Th. II to Abd. IV (Figs 8D, 9A‒E). Coxae I, II and III with 1‒ 2, 2‒ 3, and 1‒2 psp respectively, located close to longitudinal rows of chaetae. On manubrium, 2+2 dorso-apical ones on the manubrial plaques (Fig. 7A).
Clypeus and mouthparts (Figs 6D‒E, G, 8B). Clypeal area with nine chaetae arranged in three rows, with three rather long smooth chaetae in the prefrontal area; 1+1 rather short ciliated and 1+1 rather long smooth chaetae of subequal sizes in the facial area; and 1+1 rather long smooth lateral chaetae anteriorly (Fig. 6G). Prelabral and labral chaetae 4/5, 5, 4, all thin and smooth; median three chaetae of the second line longer than the lateral ones (21‒23 vs. 9 ‒11 µm); median three chaetae of the third line longer than the lateral ones (23‒25 vs. 26‒28 µm) (Fig. 8B). Distal border of the apical non-granulated median area of the labrum with a relatively narrow median U- or Vform intrusion (U form in the Fig. 8B) into the granulated area dorsally; apical edge without spines, lacking clear papillae. Maxillary outer lobe with one basal and one apical chaetae (basal chaeta thicker than the apical one) and three smooth sublobal hairs (36‒38 vs. 17‒19 µm) (Fig. 6E). Labial palp with 0, 5, 0, 4, 4 guards for papillae A‒E. Lateral process of labial palp subcylindrical, as thick as normal chaetae with tip beyond the apex of the labial papilla (Fig. 6D). Mandible apex strong, asymmetrical (left with four, right with five teeth).
Antennae (Figs 6A, C). Antennae moderately long, approximately 2.4–2.6 times as long as the cephalic diagonal. Antennal segments ratio as I: II: III: IV = 1: 1.13–1.55: 1.16–1.33: 1.90–2.06 (N = 3). Antennal segments not subdivided nor annulated. Antennal chaetal types not analysed in detail. Smooth spiny mic at base of antennae: three dorsal, three ventral on Ant. I, one internal, one external and one ventral on Ant. II, one smooth ventral on Ant. I, smooth straight long chaetae on antennae present. Ant. I ventrally with many smooth spiny mic of various sizes in its basal part, many subcylindrical, hyaline sens in its middle to apical part, and many long smooth straight chaetae. Dorsal Ant. II with two paddle-like chaetae. Ant. III organ with five sens; sens one and four subequal, hyaline; sens five acuminate, dark and shorter; sens two and three swollen. Ant. IV not subdivided, without the apical bulb. Subapical organite not much swollen, slightly enlarged apically, inserted dorsally (Fig. 6C).
Dorsal head chaetotaxy (Fig. 8A). Dorsal cephalic chaetotaxy with five antennal chaetae (An1–2, An3a2, An3a; An3 as mic), four anterior (A0, A2–3 and A5), three median (M1–2, M4) and eight sutural mac (S0, S1– 4, 4e, 5–6), Gr. II with five mac (Pi1–3, Pa1, Pp1a); 5+5 scale-like structures present below the sutural mac, inside the integument (like in Fig. 4D), (socket of scale-like structures not detected under SEM) (like in Fig. 4C); a pair of short cephalic trichobothria, external and close to the middle of the head (Fig. 8A).
Ventral head chaetotaxy (Figs 6B, F, H). Chaetae of labial basis all smooth M 1m 2rel 1 l 2 (or Mimrel1l2 sensu Zhang & Pan 2020), chaetae m, e and l 1 subequal, r thin and shortest, ratio of r to m2 0.10‒0.19 (Figs 6B, 6F). Postlabial chaetae H1 ciliated, X, X 2, X 4 as spiny mic; X 3 absent (Fig. 6F). Each side of the cephalic groove with seven chaetae, the first anterior 1 st –3 rd always long and smooth, 4 th –7 th always ciliated, sometimes small or long chaetae (Figs. 6F. 6H).
Tergites (Figs 8D, 9A–F). Th. II with four (m1, m1i, m2, m2i) medio-medial, four (a5, m4, m4i, m4p) mediosublateral and 34 posterior mac; 1+1 ms and 2+2 sens laterally (Fig. 8D). Th. III with 40 mac, m6 and m6ai as mac, 2+2 sens laterally (Fig. 9A). Abd. I with eight (a1, a1e, a2‒3, a5, m2–4) central mac, 1+1 ms and 1+1 sens laterally (Fig. 9B). Abd. II with five (a2‒3, m3, m3e, m3ep) central and one (m5) lateral mac. 2+2 tric without modified surrounding chaetae, 1+1 sens laterally and 1+1 sens above m3 (Fig. 9C). Abd. III with two (a2, m3) central, and three (am6, pm6, p6) lateral mac. 3+3 tric without modified surrounding chaetae, 1+1 sens laterally, 1+1 sens near a2 (Fig. 9D). Abd. IV with seven central mac (A3, A5‒6, B4‒6, Sm) and nine (D3, E2, E2p, E3–4, Ee8, F1–2, F3a) lateral mac, 2+2 tric and about 8 long S-like chaetae anteriorly, without modified chaetae (Fig. 9E). Abd. V with at least eight obvious mac (a5, m2‒3, m5, p1, p3‒5) and several mes or small mac, and 3+3 sens (Fig. 9F). Abd. VI not analysed.
S-chaetae formula from Th. II to Abd. V: 2+ms, 2/1+ms, 2, 2, ≈ 8, 3; ps and as sens on Abd. IV 1/2 as long as S-like chaetae (Figs 8D, 9A–F).
Legs (Figs 7C‒F, 8C). Legs moderately long; tita of leg III slightly longer than tita of legs I and II. Legs devoid of scales, covered with ordinary ciliated chaetae of various lengths, mic not seen. Tibiotarsi II and III (Fig. 7C) with one large inner ciliated mac at about 1/3 from basal side. Trochanteral organ with about 18 smooth, straight, unequal spinelike chaetae (Fig. 8C). The distal whorl of tita with 9‒10 subequal ciliated mes, irregularly arranged, and dorso-apical pointed tenent hair present. Smooth, thin and long chaeta close to the tenent hair absent. Ventro-distal smooth chaeta of tita III thick, erected, pointed, rather short. Claw elongated. Unguis with one small unpaired inner tooth at 53‒61%, and a pair of subequal basal teeth at about 46‒50% of inner edge from basis. Unguiculus approximately 2/3 as long as the inner edge of the claw, narrow and not swollen baso-externally, pointed apically, with a few minute outer teeth, often inconspicuous in the middle of its length in claw II and III, without outer teeth in claw I (Figs 7D‒F).
Ventral tube (Figs 8E‒G). Ventral tube two to three times longer than wide. Lateral flaps with 6‒8 + 6‒8 chaetae, all smooth chaetae of unequal sizes. (Fig. 8E). Anterior face with 6‒8+6‒8 ciliated chaetae, 2 of them apically larger than the others (Fig. 8G); posterior face with 2+2 more apical smooth chaetae 1 unpaired ciliated chaeta just under the pair of smooth chaetae, 1+1 smooth chaeta at the distal region, the middle chaetae with seven chaetae (three smooth and four ciliated chaetae of unequal sizes) (Fig.8F).
Furcal complex (Figs 6I, 7A‒B). Tenaculum with four large teeth of decreasing sizes from the basal to the distal one on each ramus, on a prominent, irregular corpus, with a postero-basal strong serrated chaeta bent distally. Mucrodens 1.30‒1.33 times longer than the manubrium. Furcula without smooth chaetae. Manubrium densely covered by ciliated chaetae both dorsally and ventrally. Manubrial plaque with 2+2 pseudopores and two ciliated chaetae (Fig. 7A). Distal part of the ventral manubrium with 10+10 ciliate chaetae (Fig. 7B). Dens without spines, annulated and covered with ciliated chaetae on both sides. Distal smooth part of dens as long as the mucro. Mucro strong and falcate, basal spine long, beyond the tip of the mucronal tooth (Fig. 6I).
Genital plate. Female genital plate with 2+2 genital mic.
Ecology. Coecobrya cavicola sp. nov. is restricted to the dark zone of the cave where it was found, in an oligotrophic environment with a rather large population of individuals. Most specimens were found on the cave floor, which was muddy ground, on stalagmites and on the rock walls. The temperature in the dark zone was 25.0‒ 26.2°C and the relative humidity was 85‒91%.
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Legends: (s) = smooth; (c) = ciliated; numbers within parentheses = variations of the chaetotaxy. Data based in the original descriptions.
Etymology. The name of the new species is derived from the Latin stem “ cav- ” which means “hole” and “ col- ” which means “to dwell”, referring to the habitat of this new species which is restricted to the subterranean environment.
Remarks. The overall profile of Coecobrya cavicola sp. nov. is intermediate between the non-troglomorphic and troglomorphic groups of species, as it is rather small, and its antennae are not elongated compared to other described highly troglomorphic species (see Table 3). However, here it is placed into the troglomorphic group as it has rather moderately long appendages, slender and elongated claws, as well as being eyeless and depigmented. It is also worth noting that its habitat is an oligotrophic area within the wet and humid dark zone of a cave. Among all the described troglomorphic Coecobrya species in Thailand, C. cavicola sp. nov. differs from them especially in the number of posterior mac on Th. II (20), and the number of mac on Abd. I (5), (Table 1). It is apparently closer to C. cavicta from a cave in Satun province, southern Thailand, by having similar antennal length (Ant./head = 2.4‒2.6 times); long smooth straight chaetae on Ant. II present; number of dorsal head in A (4 mac) and M areas (3 mac); number of sublobal hairs of labial palp (3), number of mac on the medio-sublateral area of Th. II (3); lateral mac of Abd. III (3) and pointed tenent hairs. However, the new species is clearly different from C. cavicta in: the number of dorsal head mac of An area (2 vs 4); number of chaetae in Gr.II (5 vs 4); labial chaetae formula (M 1m 2rel1l2 vs mrel1l2); number of chaetae along the cephalic groove (3s1‒4c vs 3‒4s7‒8c); number of mac on medio-medial area of Th. II (4 vs 3); posterior mac of Th. II (34 vs 30‒31); mac on Th. III (40 vs 35); central mac on Abd. II (5 vs 3); central mac on Abd. III (2 vs 1); ms on And. III (present vs absent); lateral mac on Abd. IV (8 vs 11); number of smooth chaetae of the trochanteral organ (18 vs 15‒16); number of chaetae on manubrial plaque (2 vs 4); number of chaetae on ventraldistal part of manubrium (10 vs 13) and mucronal spine (beyond vs nearly reaching the mucronal apex).
description: Published as part of Nilsai, Areeruk, Zeppelini, Douglas, Bellini, Bruno C., Lima, Estevam C. A. & Jantarit, Sopark, 2022, First record of the boneti-group of Coecobrya Yosii, 1956 (Collembola Entomobryidae) from Thailand, with the description of three new cave species of the genus, pp. 365-392 in Zootaxa 5214 (3) on pages 374-381, DOI: 10.11646/zootaxa.5214.3.3, http://zenodo.org/record/7389184