Alloscopus jantapasoae Jantarit, Nilsai & Manee, 2025

Jantarit, Sopark, Manee, Nongnapat, Nilsai, Areeruk, Mitpuangchon, Natrada & Pimsai, Awatsaya, 2025, Two new species of the genus Alloscopus Börner, 1906 (Collembola, Orchesellidae, Heteromurinae) from southern Thailand, ZooKeys 1245, pp. 357-381 : 357-381

Alloscopus jantapasoae Jantarit, Nilsai & Manee sp. nov.

Figs 1 , 2 , 5 , 7 , 8 ; Table 1

Material examined.

Holotype: • female on slides: sample # THA_SJ_TRG 03 ; Thailand: Trang: Huai Yot District, Pak Chaem subdistrict; Tham Khao Tang Lon (note: “tham” = “cave” in Thai): 7°42'19.1"N, 99°41'12.2"E, 170 m asl, by aspirator, coll. S. Jantarit, 21 xii 2019 . Paratypes: • collection data same as holotype; on slides: • seven samples, • one female and • six subadults, by aspirator .

Description.

Habitus (Fig. 2 C, D ). Medium sized Orchesellidae . Body length (head + trunk) up to 1.7 mm. Scales present on both sides of Ant. I – II, on both sides of head, body, legs (coxa to femur), ventral tube and furca. Color whitish in ethanol with orange dotted pigments on antennae, head, body, legs and furca (Fig. 2 C ). Dark red ocular patch presence. Antennal length shorter than the body. Eyes absent. PAO shape irregular (three overlapping ovals) located just below antennal mac. Body slender, not bent nor humped at level of Th. II.

Pseudopores (Figs 5 B , 9 A ) present as round flat disks, as large as mac sockets, present on various parts of body: antennae, head, tergites, coxae and manubrium. Antennae with psp located on tip of Ant. II and III (2 on each segment). Head with 1 + 1 psp laterally, anterior to PAO. Tergites, 1 + 1 psp near axis, from Th. II to Abd. IV (Fig. 5 B ). Sternite of Abd. IV with one psp near tenaculum. Coxae of legs I – II with 1 + 1 psp near longitudinal rows of chaetae (Fig. 9 A ). On manubrium with 2 + 2 dorso-apical ones.

Antennae (Fig. 8 A ). Slightly longer, ~ 1.59–2.0 × cephalic diagonal, and 0.28–0.41 × body length (head + trunk) (n = 6). Ant. I subdivided, Ant. III and IV annulated, except proximal and distal part (Fig. 2 ). When Ant. II and III fused, segments not annulated. Antennal segment ratio as I (a + b): II: III: IV = 1: 1.1: 1.25: 1.6. Antennal chaetae diverse: ordinary chaetae, S-chaetae (as described in Jantarit and Sangsiri 2020) and scales. Scales oval to rounded, of medium size (7–13 × 14–28 μm), with dense cover of short spicules arranged in more or less regular longitudinal lines; numerous dorsally on Ant. Ib and Ant. II, few on Ant. Ia dorsally; absent on Ant. III and IV. Sense and sens - like chaetae present on all antennal segments, of 13 morphological types similar to that described by Jantarit and Sangsiri (2020), not re-described in detail here.

Ant. I subdivided into Ia and Ib (Fig. 8 A ). Ant. Ia shorter than Ib. Ant. Ia dorsally with three basal mic (type g) and few thick ciliated chaetae (type b); ventrally with three basal mic (type g), three pointed smooth mes (type e), one hyaline, smooth mic (type m) and three thick ciliated chaetae (type b). Ant. Ib dorsally densely covered with scales and ciliated chaetae (types a and b), with a smooth basal mic (type g); apical row with two or three hyaline, smooth mic (type m), one pointed smooth mes (type e) and one thin, long, hyaline S-chaetae (type l). Ventrally with a dense cover of ciliated chaetae (types a and b); apical row with three pointed smooth mac (type d) and three or four pointed smooth mes (type e or f); lateral side with two or three large swollen, blunt S-chaetae (type h), four or five thin, long hyaline mes (type l) mixed with other three types of S-chaetae (types e, i, k) variously interspersed.

Ant. II dorsally with scales mixed with many thick ciliated chaetae (types a and b), distally with 5–7 pointed smooth mes (type e or f); one or two swollen S-chaetae (type h); four thin, long hyaline mes (type l); one or two thin hyaline rather short chaetae (type k); basally with three pointed smooth mic (type g). Ventrally with a dense cover of thick ciliated mes (type b) with two pointed smooth mic (type g) basally, mixed with two pointed smooth mac (type d), one short, pointed, rather bent apically (type 7), three or four large swollen S-chaetae (type h), 8–10 thin, long hyaline S-chaetae (type l), and 8–10 pointed smooth mes (type e or f).

Ant. III without scale, chaetotaxy without tendency to form whorls of chaetae. Dorsally dense cover with many thick ciliated mes (types b and c) with two pointed smooth mic (type g) basally, mixed with six types of S-chaetae (types e, f, h, i, k, l) variously interspersed. Ventrally with a dense cover of many thick ciliated mes (type b) with two pointed smooth mic (type g) basally, mixed with four types of S-chaetae (types e, f, h, l) variously interspersed. Ant. III organ with five sens; sens 1 (type m) longest, hyaline, and acuminate; sens 4 (type i) hyaline, rather long, blunt apically; sens 5 (type j) dark, shortest; sens 2 and 3 (type h) swollen curving rods. Antennae sometimes asymmetrical due to the fusion of Ant. III and IV, Ant. III distal chaetae strongly modified when Ant. III and IV fused.

Ant. IV annulated, except at tip, without apical bulb, chaetotaxy with tendency to form whorls of chaetae. Dorsally dense cover with many thick ciliated mes (types b and c) mixed with four types of S-chaetae (types e, f, k, l) variously interspersed. Ventrally dense cover with many thick ciliated mes (types b and c) mixed with four types of S-chaetae (types e, f, k, l) variously interspersed. Pin projection on apex not seen. Subapical organite not distinctly knobbed, apical not enlarged, inserted dorsally near the tip of Ant. IV with apical guard chaetae.

Mouthparts (Fig. 8 B, D, E ). Prelabral and labral chaetae 4 / 5, 5, 4, all smooth, acuminate, subequal; except chaetae of proximal row slightly longer than others (Fig. 8 B ). Four labral papillae, conical, minute. Ventral complex of labrum with two slightly asymmetrical multi-toothed combs and a pair of thin, sinuous, unequal tubules below. Maxillary outer lobe with one basal chaeta, simple maxillary palp, four sublobal appendages, all smooth (Fig. 8 B, E ). Labial palp with five smooth, acuminate proximal chaetae and five papillae (A = 0, B = 5, C = 0, D = 4, E = 5), and hypostomal chaeta (H) with two accessory appendages (h 1 and h 2). Labial papilla E with lateral process subcylindrical apically, reaching papilla apex (Fig. 8 B, D ). Mandible asymmetrical (right with 4 and left with 5 teeth) on all examined specimens. Molar plate with three to four strong pointed basal teeth. Maxilla with strong tridentate claw, four or five stout ciliated lamellae with two or three well-developed sharp beaks each side opposite to maxilla capitulum, and thin rod, long, bent inwards towards capitulum.

Ventral head chaetotaxy (Fig. 8 C ). Labial basis as M 1 m 2 _ el 1 l 2: chaetae M 1 ciliated, m 2, l 1 and l 1 subequal and longest, r absent, maybe as scale (Fig. 8 C ). Postlabial quadrangle (PLQ) with 2 + 2 weakly serrated chaetae. Ventral head with a dense cover of scales and weakly serrated chaetae.

Dorsal head chaetotaxy (Figs 5 B , 8 A ). Dorsal cephalic chaetotaxy with stable chaetae arrangement (Fig. 5 B ). ‘ An’ series with 9 + 9 chaetae, all mac, ‘ A’ series with 4 + 4 mac (A 0, A 2 – A 4), A 1 as mic; ‘ M’ series with 3 + 3 mac (M 1 – M 3), sutural mac with 7 + 7 mac (S 0, S 1, S 3–6, S 6 i), and three unnamed mic between series ‘ M’ and ‘ S’; interocular series with 3 + 3 chaetae (p as mac, t as mes, r as mic); postsutural area with 3 + 3 mic (Ps 2–3 and 5); postoccipital anterior area with 1 + 1 mac (Pa 5), 1 + 1 short cephalic tric (Pa 6) and 1 + 1 unnamed mic laterally; postoccipital posterior area with 3 + 3 mic (Pp 3 and Pp 5–6); head laterally with several unnamed mac (Figs 5 B , 8 A ).

Tergites (Fig. 5 B ). Dorsal chaetotaxy illustrated in Fig. 5 B . Formulas for Th. II – Abd. V: psp formula as 1, 1 / 1, 1, 1, 1, 0; tric formula as 0, 0 / 0, 2, 3, 2, 0; ms formula as 1, 0 / 1, 0, 1, 0, 0; sens formula as 2, 2 / 1, 3, 3, 3, 3; mac formula as 11, 7 / 3, 1, 3, 7, 4. Mac arrangement stable; multiplets sensu Szeptycki (1979) present only anterior on Th. II.

Th. II with 6 + 6 anterior central mac (a 5, m 2, m 2 i, m 4, m 4 i, m 4 p) and 5 + 5 posterior mac (p 1–3, p 5, p 2 e); with 3 + 3 mic (1 p 2, p 4, acc. p 6), 2 + 2 mes (p 64, p 6) and two unnamed mes laterally.

Th. III with 6 + 6 central mac (p 1–3, p 1 a, a 4–5) and 1 + 1 lateral mac (a 6); 9 + 9 mic (a 2, m 1, m 4, p 4–6, p 2 a, m 6 p, acc. p 6) and 4 + 4 mes (a 7, m 6–7, and unnamed mes).

Abd. I with 3 + 3 central mac (m 2–4) and 7 + 7 mic (a 1–3, a 5–6, m 5, p 6) and a row of 2–3 + 2 – 3 unnamed mes laterally, not shown in the illustration (Fig. 5 B ).

Abd. II with 1 + 1 central mac (m 3); 12 + 12 chaetae (a 1–3, a 6–7, m 3 e, m 5–6, p 4, p 6 as mic; a 5 and m 2 as tric).

Abd. III with 1 + 1 central mac (m 3) and 2 + 2 lateral mac (p 6, pm 6); 13 + 13 chaetae (a 1–3, a 6–8, m 3 e, m 4, p 4–5 as mic; a 5, m 2, m 5 as tric) with two unnamed mes laterally, not shown in the illustration (Fig. 5 B ).

Abd. IV with 3 + 3 central mac (A 6, B 6, C 2); 4 + 4 lateral mac (E 3, E 4, Ee, F 1); with at least 18 + 18 chaetae (A 2–3, A 5, B 3–4, C 1, D 1–2, E 1, F 2, F 3 a, T 1, T 3 as mic; C 4, D 3, D 4 p, T 6–7 as mes; T 2 and T 4 as tric); and at least 9 + 9 S-like chaetae (most chaetae lost during slide preparation).

Abd. V with 3 + 3 central mac (m 2–3, p 1) and 1 + 1 lateral mac (m 5); with 13 + 13 chaetae (a 1, a 3, a 5, p 1 p, p 3, p 3 pi, 3 pi, 5 pi as mic, a 6, ap 6, p 4–5, m 5 a as mes) with at least two or three unnamed mes laterally, not shown in Fig. 5 B .

Abd. VI with 3 + 3 ciliated mic and at least 30 + 30 ciliated mac mixed with mes, all chaetae not shown in Fig. 5 B .

Dorsal anal valve without smooth chaetae, several serrated mes mixed with mac, mic not seen.

Legs (Fig. 9 A – D ). With ordinary ciliated chaetae of various lengths (mes to mac), smooth chaetae and scales; mic not seen. Tita of leg III slightly longer than tita of legs I and II.

Subcoxa of leg I with 3 + 3 mac, subcoxa of leg II with 3 + 3 mac and a row of 6–7 + 6 – 7 mes, subcoxa of leg III with 3–4 + 3 – 4 mac and 12–13 + 12 – 13 mes (Fig. 9 A ).

Coxa of leg I with one proximal psp, four or five anterior mes and four posterior mac; coxa of leg II with six mac in anterior row, four mac and two mes in posterior row and one proximal psp in between; coxa of leg III with 11 or 12 mes anteriorly and three mac posteriorly, psp not seen (Fig. 9 A ). Trochanteral organ with 17–22 smooth, straight, unequal spine-like chaetae.

Tita distal whorl with ten subequal ciliated chaetae, irregularly arranged, and a thin, acuminate, smooth tenent hair. Tita without rows of long smooth chaetae internally (Fig. 9 D ). Ventro-distal smooth chaeta of tita III thin, erected, pointed, longer than tenent hair or unguiculus (Fig. 9 B – D ). Pretarsal mic minute on anterior and posterior sides.

Ungues outer tooth present; inner edge with paired basal teeth, leg III with a tiny unpaired tooth (sometimes absence), legs I and II without unpaired inner teeth. Unguiculus ~ 1 / 2 as long as inner edge of ungues, slightly swollen baso-internally, pointed apically, with large outer tooth (under light microscope), devoid of inner teeth (Fig. 9 B – D ).

Ventral tube (Fig. 9 E, F ). Ventral tube ~ 1.5–1.7 × longer than wide; with scales on posterior side (Fig. 9 F ). Anteriorly with 6 + 6 ciliated chaetae, with approximately the same size (Fig. 9 E ). Posteriorly with 1 + 1 smooth chaetae and 9–10 + 9 – 10 weakly ciliated chaetae (Fig. 9 F ). Lateral flaps with 11 + 11 thin, smooth chaetae of unequal size (Fig. 9 F ).

Furcal complex (Fig. 9 G ). Tenaculum with one smooth chaeta and four large teeth of decreasing size from the basal to distal one on each ramus.

Ratio of manubrium: dens: mucro = 4.7: 7.7: 1 (n = 8).

Mucrodens 1.58–2.2 × longer than manubrium (n = 8). Manubrium dorsally densely covered with ciliated mes, with a row of 3 + 3 smooth chaetae on each side. Manubrial plate with 2 + 2 psp and four ciliated chaetae. Manubrium ventrally densely covered with medium size scales, chaetae not seen, except basally with 1 + 1 short smooth chaetae. Dens curved, tapering, constituted of a rather short basal part hardly crenulated, long medial part with well-defined dorsal crenulations and short, thinner, smooth distal part, smooth section ~ 4 × as long as mucro. Dens basally with 1 + 1 row of 3–5 + 3 – 5 finely ciliated spines on inner side (normally with 4 + 4), sometimes asymmetrical and 1 + 1 long smooth chaetae latero-externally. Laterally dens covered with ciliated mes, ventrally with medium size elongated scales mixed with ciliated mes; scales absent on distal non-crenulated part. Mucro bidentate, without basal spine (Fig. 9 G ).

Genital plate as in A. whitteni ( Jantarit and Sangsiri 2020: fig. 6 G). Female with 2 + 2 smooth mic, one pair on anterior and posterior lobes.

Remarks.

Alloscopus jantapasoae sp. nov. differs from the all other blind Alloscopus species by having 3 + 3 central mac on Abd. IV (vs 2 + 2 in all known blind species). The new species is most similar to A. namtip Jantarit & Sangsiri, 2020 from Thailand in the number of mac on head of ‘ An’ series; number and homology of mac on Th. II (11 + 11); and due to both species were collected from cave habitats. However, it differs from A. namtip in having shorter antennal length (1.2–1.6 vs 2); in the presence of orange pigments (vs absence); number of spiniform labral papillae (4 vs 2); number of mac on Abd. IV (7 vs 6); number of unequal inner unpaired teeth (0–1 (tiny) vs 1–2); number of smooth chaetae on trochanteral organ (17–23 vs 25–32); number of chaetae on anterior face of ventral tube (6 vs 9), on posterior face of ventral tube (10–11 vs 23) and number of chaetae on lateral flap of ventral tube (11 vs 12). Diagnostic characters of this new species and all seven closely related blind species are provided in Table 1 .

Etymology.

Alloscopus jantapasoae is named in honor of Ms. Kanchana Jantapaso, a member of our research team who has made significant contributions to the study of cave fauna in Thailand and assisted in the collection and analysis of cave fauna both across the country and in the laboratory.

Ecology.

The new species was collected and only known from the dark zone of a cave on ground floor with small patch of bat guano. Seven caves in the surrounding area, including Tham Khao Chang Hai — which is known for having one of the richest cave faunas in the country — were surveyed for Collembola. However, none of the specimens of this species were found in these caves, suggesting a high degree of endemism to Tham Khao Tang Lon.

Figures

Figure 1. The map of Thailand (top right) shows a rectangle outlining the southern region, with the arrow indicating an enlarged view of this area, illustrating the distribution of the new species of Alloscopus described in this study: Alloscopus jantapasoae sp. nov. (1); A. sago sp. nov. (2); A. Photograph of the cave habitat where A. jantapasoae sp. nov. was collected, showing a human figure for scale, and B. Photograph of the bark of sago palm tree, the habitat where A. sago sp. nov. was discovered.

Figure 2. Habitus of Alloscopus in this study: A, B. A. sago sp. nov. photographs from the stereomicroscope and SEM and C, D. A. jantapasoae sp. nov. photographs from stereomicroscope and SEM; E. The patch of sago palm trees (Metroxylon sagu Rottb); F. Enlarged detail of sago palm barks. Scale bars: 500 μm (B, D).

Figure 5. Head and body chaetotaxy of A. Alloscopus sago sp. nov. and B. A. jantapasoae sp. nov. Scale bars: 200 µm.

Figure 7. Alloscopus sago sp. nov. continued, A. Ventral tube, posterior view and lateral flap; B. Ventral tube, anterior view, and lateral flap; C. Dorso-lateral manubrium with red arrows indicating rows of smooth chaetae; green arrow shows a smooth chaeta on dens basally; D. Proximal part of dens and spines; E. Mucro and distal part of dens. Scale bars: 40 µm (A, B); 50 µm (C); 10 µm (D); 30 µm (E).

Figure 8. Alloscopus jantapasoae sp. nov. A. Anterior part of head; B. Mouthparts show prelabral and labral chaeta, labial palp, and maxillary outer lobe; C. Labial basis; D. Papillae E of labial palp (right side); E. Maxillary outer lobe. Scale bars: 50 µm (A, B); 20 µm (C, D, E).

Figure 9. Alloscopus jantapasoae sp. nov. (continued). A. Outer chaetotaxy of coxae I – III (left side); B, C. Distal part of tibiotarsi and claw complex; D. Tita and claw morphology; E. Ventral tube, anterior view, and lateral flap; F. Ventral tube, posterior view, and lateral flap; G. Mucro and distal part of dens. Scale bars: 20 µm (A, B, G); 50 µm (D, E, F); 30 µm (C).