Troglopedetes takensis, Surakhamhaeng 1 & Deharveng 2 & Jantarit 3, 2021

Surakhamhaeng 1, Katthaleeya, Deharveng 2, Louis & Jantarit 3, Sopark, 2021, Three new species of cave Troglopedetes (Collembola, Paronellidae, Troglopedetinae) from Thailand, with a key to the Thai species, Subterranean Biology 40, pp. 129-174 : 129

publication ID	https://dx.doi.org/10.3897/subtbiol.40.73143
publication LSID	lsid:zoobank.org:pub:6B418FD9-B1F2-4D5E-AFB5-0D4DF2395D21
persistent identifier	https://treatment.plazi.org/id/E85B3D17-ACCF-4F3F-9616-32F70190726F
taxon LSID	lsid:zoobank.org:act:E85B3D17-ACCF-4F3F-9616-32F70190726F
treatment provided by	Subterranean Biology by Pensoft
scientific name	Troglopedetes takensis
status	sp. nov.

Treatment

2. Troglopedetes takensis sp. nov.

Figs 8 View Figure 8 , 9 View Figure 9 , 10 View Figure 10 , 11 View Figure 11 , 12 View Figure 12 , 13 View Figure 13

Type locality.

Thailand, Tak Province, Tha Song Yang district, Tham (cave) Mae Usu (17°18'15.0"N, 98°09'19.9"E, 172 m a.s.l.).

Type material.

Holotype: female on slide, Tak Province: Tha Song Yang district, Tham (cave) Mae Usu, 17°18'15.0"N, 98°09'19.9"E, 145 m a.s.l., 7 March 2019, S. Jantarit, A. Nilsai and K. Jantapaso leg., dark zone of cave, by aspirator (sample # THA_SJ_TAK03). Paratypes: 5 paratypes on slides (all subadult), same locality and date as the holotype.

Holotype and 5 paratypes deposited in NHM-PSU, measurements of holotype in Table 2 View Table 2 .

Description.

Habitus. Troglomorphic, slender, with elongate legs, furca and antennae. Length: 1.9-2.0 mm (n = 4) (body 1.4-1.6 mm, head 0.4 mm). Fourth abdominal segment 4-5 times (n = 4) longer than the third one along the dorsal axis. Furca well developed, about 1.4-1.5 (n = 3) times shorter than the body length. Body colour white with spots of orange pigment. Eyes not detected, but with 2+2 pigmented ocular patches.

Chaetal types . Four types of chaetae on somites, appendages (except antennae) and mouthparts: scales, present on antennal segment I and II, head, body and ventral side of the furca, absent on legs and ventral tube; ordinary chaetae on all body parts; S-chaetae and trichobothria on tergites; hairs devoid of sockets on outer maxillary lobe. Chaetal types on antennae are much more diverse and described separately further.

Pseudopores (Figs 8A View Figure 8 , 9A-D View Figure 9 , 11B View Figure 11 ). Pseudopores present as round flat disks larger than mac sockets, on antennae, head and tergites. Head pseudopore sometimes present aymmertrically on one side only. Dorsal pseudopore formula: 1/1, 1/1, 1, 1, 1+4 (Figs 8A View Figure 8 , 9A-D View Figure 9 ). On antenna, 1 psp detected ventro-distally on Ant. I (Fig. 11B View Figure 11 ), without psp on Ant. II and Ant. III. On head, 1 psp close to antennal basis (Fig. 8A View Figure 8 ). On legs, psp present externally on coxae (1-(2) for legs I and II and 2 for leg III). On manubrium, 2 psp on the dorso-distal plaque; on each dens, 2 psp dorso-basally near the internal spine row.

Mouthparts. Clypeus with 13 large mes, symmetrically arranged: 9 ciliated posteriorly and 4 thin smooth anteriorly (Fig. 8F View Figure 8 ). Labral formula 4/5,5,4 (Fig. 8E View Figure 8 ); prelabral chaetae short, bent and ciliated, labral chaetae thinner, longer, smooth and acuminate, those of the distal row slightly larger and longer than those of the median row; the anterior line not concave in V or U-shape. Ventro-distal complex of labrum well differentiated, asymmetrical, with 2 distal combs (a larger one with 8-9 teeth on the left side, a smaller one with 13-14 minute teeth on the right side) and an axial pair of sinuous tubules. Distal part of labrum not adorned with spines dorso-distally. Labial palp similar to that described by Fjellberg (1999) for Troglopedetes sp., with strong papillate chaetae. Number of guards for each major papillate chaetae: A (0), B (5), C (0), D (4) and E (4); lateral process subcylindrical, surpassing the apex of papilla E (Fig. 8B View Figure 8 ); 5 proximal chaetae. Chaetae of labial basis as M1M2REL1l2, with M1, M2, R, E, L1 subequal and ciliated, l2 short, smooth and acuminate (Fig. 8G View Figure 8 ). Outer maxillary lobe with 1 papillate chaeta, 1 basal chaeta longer than the others and 2 sublobal hairs (Fig. 8C View Figure 8 ). Maxillary head with a 3-toothed claw, several stout shortly ciliated lamellae not observed in detail and 2 thin elongate structures (1 dorsally and 1 ventrally). Mandible head strong, asymmetrical (left side with 4 teeth, right side with 5); molar plate with 3 strong pointed basal teeth, and other 2-3 inner distal teeth, identical in both mandibles.

Antennae (Figs 11 View Figure 11 - 13 View Figure 13 ). Antennae elongated (1,274-1,524 µm, n = 4), slightly shorter than body+head length (n = 3), and 3.2 times (n = 4) longer than the cephalic diagonal. Ant. IV subdivided into two segments, asymmetrically arranged with Ant. IVa longer than IVb (0.57 : 0.43, n = 4), without apical bulb (Fig. 13D View Figure 13 ). Lengths of antennal segments I to IV (IVa+IVb) as 1:1.9:1.9:3 (average, n = 4). Antennal chaetae (scales, 5 types of ordinary chaetae, 13 types of S-chaetae and subapical organit) described separately.

General chaetotaxy (Figs 8A View Figure 8 , 9A-D View Figure 9 ). Body scales densely covered with oval scales; ventro-lateral scales larger than the dorsal ones; posterior scales of tergites larger than the anterior ones (24-40 µm long).

Dorsal macrochaetae formula: 0,2/8,4/0,2,4,3 (Figs 8A View Figure 8 , 9A View Figure 9 ). Trichobothrial pattern : 1/0, 0/0, 2, 3, 3 (Figs 8A View Figure 8 , 9A View Figure 9 ). Trichobothrial complexes well developed with modified mes of various sizes (Fig. 9A-D View Figure 9 ) described below for each segment. The figured mes pattern not complete.

Head chaetotaxy (Fig. 8A, G View Figure 8 ). Head with 11-14 peri-antennal mac in line on each side, no central mac. Cephalic mes short, feebly serrated, equal, 15+15 symmetrically arranged (Fig. 8A View Figure 8 ). One lateral cephalic trichobothria much shorter than the closest mac on each side; suture zone not visible (Fig. 8A View Figure 8 ).

Head dorsally densely covered with round to oval scales (33-45 µm long). Ventral chaetotaxy of head densely covered with oval scales (57-67 µm long), postlabial chaetae along the linea ventralis as ciliated mes anteriorly and 3 ciliated chaetae laterally, one mac and an oblique line of 5-6 mes posteriorly on each side (Fig. 8G View Figure 8 ).

Tergite chaetotaxy (Fig. 9A-D View Figure 9 ). Th. II with a collar consisting of a few rows of mac along its anterior and antero-lateral margins, a compact group of 6 central mac on each side and 2 antero-lateral mac; 1 antero-lateral ms; 1 antero-lateral sens, mes to mic not counted centrally (Fig. 9A View Figure 9 ).

Th. III with 4 mac by side (a group of 3 central and 1 anterior to them), 1 sens at antero-lateral margins, and about 12 mac or long mes at lateral margins (Fig. 9A View Figure 9 ).

Abd. I without central mac, with 1 ms laterally on each side, a row of 3 mics below psp, a6 absent, and 5 mes laterally (Fig. 9A View Figure 9 ).

Abd. II with 2 tric on each side and 6 modified mes around them (2 around the internal tric and 4 near external tric), 2 mac (1 near internal tric and 1 near external tric), 1 sens near internal tric, 4 mic (1 close to internal tric and 3 close to external tric), at least 3 other mes at lateral margins (Fig. 9A, B View Figure 9 ).

Abd. III with 3 tric on each side (1 internal, 2 external) and 8 modified mes around tric (2 near internal tric, 6 near the two external tric); 4 mac (1 near internal tric and 3 near external tric); 1 sens anterior to internal tric and 1 ms; at least 5 mes to small mac at lateral margins (Fig. 9A, C View Figure 9 ).

Abd. IV with 3 tric on each side (2 antero-lateral, 1 postero-lateral) and about 7 modified mes around the two antero-lateral tric; postero-lateral tric with 1 modified mes. Mac distributed as 3 central on each side (1 antero-external to pseudopore, 2 anterior to posterior tergite margin), 1 near postero-lateral tric, and at least 5 external, mixed with at least 14 mes or smaller mac on lateral to posterior margins; 3 sens; at least 4 S-like chaetae sensu Lukić et al. (2015) anteriorly, and at least 5 mes or short S-like chaetae uniformly distributed; at least 1 serrated mes in line in the posterior row along pseudopore line (Fig. 9A, D View Figure 9 ).

Abd. V with 2 sens detected on each side, and several ordinary chaetae from mes to mac, not counted (Fig. 9A View Figure 9 ). Abd. VI chaetotaxy not analyzed.

Legs (Fig. 10A, B View Figure 10 ). Legs long. Tita III as long as the head diagonal, slightly longer than Tita I and II. Legs devoid of scales, mostly covered with ordinary ciliated chaetae of various length, from mes to mac. Trochanteral organ of leg III with 15-17 smooth, straight, unequal spiny chaetae (n = 3) (Fig. 10B View Figure 10 ). Tibiotarsus chaetotaxy mostly composed of strong ciliated-serrated mes, the basal ones longer and thicker (50-70 µm), slightly shorter distally (up to 35-45 µm). Distal row with 7-9 subequal ciliated mes and a dorso-apical tenent hair thin, pointed on all tita; a ventro-distal strong smooth erected chaeta present on Tita III (Fig. 10A View Figure 10 ). Praetarsal mic minute (3.5-4 µm), clearly seen in one side (Fig. 10A View Figure 10 ). Unguis in all legs slender and long (60-65 µm long, 13 µm wide at basis), 7 times shorter than tita, with a pair of inner basal teeth of equal size, one uneven inner basal tooth, outer edge with a minute tooth at 20-23% usually inconspicous; unguiculus pointed, narrow, lanceolate and elongate, about 0.6-0.7 times shorter than the claw, its external edge irregular with at least 4-9 toothlets (Fig. 10A View Figure 10 ).

Ventral tube (Fig. 10D, E View Figure 10 ). Ventral tube about 3.8 times longer than wide, with 3+3 long serrated mac anteriorly and 7 mes (3 ciliated and 4 smooth) on each lateral flap (Fig. 10E View Figure 10 ); posterior side with at least 39 ciliated mes, 2 smooth mes and 7 small spines (Fig. 10D View Figure 10 ).

Furca complex (Fig. 10C View Figure 10 ). Tenaculum with 4 teeth on each ramus, of decreasing size from the basal to the distal one, on a prominent, irregular body, with a postero-basal strong, densely serrated, distally bent chaeta. Manubrium about 1.13 times (n = 4) shorter than the mucrodens (mucro+dens). Manubrium dorsally with subequal ciliated mes (none smooth), irregularly arranged in 3-4 rows in two longitudinal stripes separated by a glabrous axial stripe, external row of chaetae distally with at least 11-19 long ciliated mac, dorso-distal plaque with 4+4 mes and 2+2 pseudopores. Ventrally with a dense cover of round to oval (25-57 µm long) and thin elongated scales (25-40 µm long). Dens straight, elongate, hairy, slightly and progressively tapering, dorsally with 2 rows of spines, mixed with ciliated mes of various length, thickness and shape. Dorso-external row with 23-28 spines, dorso-internal row with 33-40 spines (asymmetries between dentes); external spines larger and less sclerotized than the internal ones. Some short ciliated mes interspersed with spines in the external row; dorsally between the two rows of spines a mix of short and long ciliated mes, irregularly arranged in one row distally turning to 3-4 rows proximally; laterally, many short ciliated mes; dorso-distally, 3-(4) stronger ciliated mes; 2+2 psp on dorso-basally between the two rows of spine. Dens ventrally entirely and densely scaled, the scales elongate (15-27 µm long) (oval shape distally), arranged in short lines from 3-5 (distally) to 6-8 scales (proximally). Mucro rather stout, short, 10.6-12.1 (n = 4) times shorter than dens, with 4 main teeth, the apical one blunt and strong, the subapical one acute and strong, a latero-distal one small and acute, and 1 dorso-basal, minute, acute and strong, with one toothlet basally (Fig. 10C View Figure 10 ).

Ecology.

T. takensis sp. nov. is only known from a large chamber in the dark zone of a cave. Specimens were found as small populations in an oligotrophic habitat, i.e. on the wall and ground surface, with a very humid and wet environment, with small trace of organic matter. Air temperature in the chamber was 22.2-23.0 °C, soil temperature was 21.9 °C and the relative humidity was 85%.

Etymology.

The species name is derived from the name of the province (Tak) where it was found.

Remarks.

Troglopedetes takensis sp. nov. has elongated antennae (the ratio of antenna: head is 3.2), legs and furca (Table 2 View Table 2 ), but shorter than in T. spectabilis sp. nov. It presents two distinct black small eye-patches on each side and lacks central mac on the head. Claws usually have only one uneven inner basal tooth (with 2 specimens without uneven inner tooth on claw III). T. takensis sp. nov. shares with T. calvus Deharveng & Gers, 1993 the absence of central mac on head. However, the new species differs from T. calvus in size (1.9-2.0 vs 0.9-1.4), presence of eyes-patches (2+2 vs 0), length of antenna (1,274-1,524 µm vs 747 µm), tenent hair (pointed vs clavate), inner teeth of claw ((0)1 vs 2), internal row of dental spines (33-40 vs 14-32).