Cyphoderus albinus Nicolet, 1842

Several characters of taxonomic importance were discovered or re-appraised in the course of this study.

1) All antennal segments were examined on both dorsal and ventral sides, revealing 10 types of chaetae (Fig. 3A). Their distribution pattern on the antennae is complex, but similar in the two species. Similarities are also obvious with the few Entomobryoidea where antennal chaetotaxy has been described. For instance, sens 1 to 5 and 8 of AIIIO as figured in Sinella by Chen and Christiansen (1993) were easily retrieved in our Cyphoderus (Fig. 3G). Several of the chaetal types recognized here are also found in other genera of Entomobryoidea. However, patterns are very complex and their comparisons would require detailed analyses beyond the scope of this paper.

2) S-chaetae can be grouped in four types (Fig. 4A), with chaeta S4 difficult to distinguish from type-5 mes. The S-chaetae formula observed in our species, as well as in other unidentified ones of the bidenticulati group, is 0/2, 1/1, 2, 3, 4, 3, 0 from head to Abd.VI (Figs 4–6), including 0/1, 0/1, 0, 1, 0, 0 for S1; 0/1, 1/0, 1, 0, 0, 0 for S2, 0/0, 0/0, 1, 2, 2, 3 for S3 and 0/0, 0/0, 0, 0, 2, 0 for S4. This S-chaetae pattern is similar to that of Entomobryoidea, except for the position of chaetae S1 and S2 on Th.II. In Entomobryoidea, S1 and S2 (=ms and S in Zhang et al. 2009) are close each other antero-laterally on the tergite (see Zhang et al. 2009). In the examined Cyphoderus, S2 is not close to S1, but intermediate between the position of antero-lateral S2 and of the postero-lateral S2 as observed in several Entomobryidae.

3) Pseudopores on tergites are arranged as in the Entomobryoidea species where they have been recorded (Jordana 2012 for instance): 1, 1/1, 1, 1, 1, 0, 0 from Th.II to Abd.VI. The presence of dorso-distal pseudopores on manubrium (2+2 in the studied Cyphoderus, Fig. 7H, 8D) is also characteristic of Entomobryoidea. Special to Cyphoderus described here are the 2+2 pseudopores behind the posterior row of chaetae of Abd.IV, found also in other unidentified Cyphoderus of the bidenticulati group (Fig. 4B). This pseudopore location is only known in Troglopedetinae, i.e., in Troglopedetes (Deharveng 1988), in Cyphoderopsis (Jantarit et al. 2013) and in Trogolaphysa (Soto-Adames and Taylor 2013), with a number of pseudopores different for each genus. A ventral pseudopore is present on antennal area, in the same location as in Isotomidae (Deharveng 1979), Neanuridae (Deharveng 1983) and Onychiuridae (Pomorski 1998, Martinez et al. 2004). At least, the presence of 1+1 or 2+2 pseudopores on head anteriorly to the antenno-basal line (Fig. 2H) is a new pseudopore location for Collembola, unnoticed as far as we know in other genera of the class.

4) Important features of dorsal head chaetotaxy have been discovered by Yoshii (1980, 1987, 1992), useful for characterizing the family Cyphoderidae and several taxa of lower rank. The number and arrangement of post-labial chaetae as well as the presence of one mic among them are the same in the two species described here. However, they differ when compared with other species and might provide another promising set of taxonomic characters.

5) Body chaetae of various types were detected and tentatively grouped in categories. The mes of type-5 are the most numerous chaetae dorsally. They are seen as smooth under microscope examination, but serrated under SEM, Fig. 4A5; distinguishing them from S4 sens is especially difficult on Abd.IV where both are present, and the same confusion may arise for many other Entomobryoidea. As patterns of these mes as well as those of S4 sens seem to be stable inside population and different between species, further investigations will have to re-examine this character for its use in taxonomy.

6) The chaetotaxy of dorsal side (Figs 4–6) matches in most cases that given by Szeptycki (1979) for Cyphoderus albinus, and is very similar to that of Entomobryoidea (see Zhang et al. 2009). Main differences include the relative position of S1 and S2 on Th.II (see above), and chaeta “as” of Th.III as a mes in our material versus a short S-chaetae in Szeptycki (1979).

7) One of the most important characters for differentiating species of the bidenticulati group is claw morphology, and it is the most diagnostic feature of the species described here. Although some variability in size and position of the various dental teeth has been noticed by other authors, it has not been taken into account in previous descriptions, leaving doubts about the validity of several species.

Thailand: Songkhla Province, Rattaphum District, Tham Khao Nui (12°12.227'N, 99°59.524'E), 120 m. above sea level, dark zone in cave, pitfall traps and Berlese extraction, S. Jantarit leg, 05 May 2012 (Sample #Songkhla-SJ.001).

Holotype, male adult (#PSUZC2011.SONG-001H) and 44 paratypes (6 males, 3 females, 35 of unknown gender) mounted on slides. Holotype and 29 paratypes at PSU (25 slides, 4 males, 2 females and 23 subadults, collection #PSUZC2011.SONG-001P-030P) and 15 paratypes at MNHN (12 slides, 2 males, 1 female and 12 subadults).

Habitus thick (Fig. 2A), not troglomorphic, body length about 1.2 mm excluding antennae and furca. Furca well developed, about 2.5 times shorter than body. Body color white. Eyes absent, no ocular patch. Dense cover of scales on head, body and furca (ventrally on manubrium, both sides on dens); scales present on Ant.I–II dorsally, absent on legs and ventral tube. Four categories of chaetae: ordinary chaetae (mac, mes and mic), scales, trichobothria and S-chaetae (= sens), described below separately for antennae and body.

Mouthparts. Outer maxillary lobe with one basal chaeta, a simple palp and one sublobal hair (Fig. 2B). Maxilla with 3-toothed capitulum and complex of 5 pad-shaped lamellae not analyzed in detail (Fig. 2C). Mandible head stocky, asymmetrical with 5 (left) and 4 (right) teeth (Fig. 2D). Labial palp with 5 papillae (A-E) and 13 guards, exactly as figured by Fjellberg (1999: fig. 72) (A and C without guards, B with 5 guards, D and E with 4 guards each); three hypostomal chaetae present with H longer than h1 and h2; 4 proximal chaetae (Fig. 2E). Labial basis formula m, e, l1, l2, with all chaetae smooth or indistinctly serrated, and l2 reduced to a minute but thick mic (Fig. 2G). Labral formula 4/5, 5, 4 with all chaetae smooth; two chaetae of the mid-row stronger and longer than others; dorso-distal limit of primary granules with a deep central incision (Fig. 2F); labral edge without structure; ventro-distally, two asymmetrical combs with many teeth variously developed and two central tubules (Fig. 2C).

Antennae. Less than 2 times the length of the head, segmentations I: II: III: IV as 1: 2.7: 1.6: 3.9. Sens and sens-like chaetae present on all antennal segments, of 10 morphological types (Fig. 3A); type-3 mes rather long, smooth under microscope examination but ciliated under SEM as in Fig. 3A (type-3*). Scales present dorsally on Ant.I and II (Fig. 3A11). Ant.I dorsally (Fig. 3B) with scales and ciliated mes (type-1), except 3 basal mic (type-9); ventrally (Fig. 3C) with various types of chaetae (types-1, 2, 3, 5, 6 and 9). Ant.II (Fig. 3D, E) dorsally and ventrally with numerous slender sens and chaetae (types-1, 3, 4, 5, 6, 7); scales present dorso-basally; distally, 3–4 dorso-external swollen sens of type-7 and one ventro-external pseudopore. Ant.III (Fig. 3F, G) with various types of chaetae (types-1, 3, 4, 5, 6, 7, 9, 10) not analyzed in detail; dorso-externally, AIIIO (Fig. 3H) typical of Entomobryoidea, with sens 1 to 5 and 8easily recognized, 2 and 3 being swollen sens of type-7; ventro-externally, one subapical pseudopore. Ant.IV (Fig. 3I, J) devoid of apical bulb, with various types of chaetae (including all types of sens except type-10); subapical organ present dorso-externally as a short and thick rod.

Body chaetae (Fig. 4A).

1) trichobothria, ciliated, very long and thin

2) weakly serrated, spiny mes

3) serrated or ciliated chaetae, of various length (mes to mac) and thickness

4) short and thickened mes in trichobothrial areas

5) thin mes, smooth under microscope examination, but ciliated under SEM

6) thick minute mic f0 and X on head

7) thin minute mic of anal valves

S1) smooth, dark, short, straight, pointed sens

S2) smooth, hyaline, short, subcylindrical, blunt sens

S3) smooth, hyaline, longer, thinner sens

S4) smooth, rather long, rather thick, blunt sens

Scales oval to rectangular in shape, of various size, covering the whole body dorsally.

Dorsal chaetotaxy and pseudopore patterns (per side).

Macrochaetae: 0/0, 0/0, 0, 1, 2 from head to Abd.IV (excluding the antenno-basal lines on head and the 7–8+7–8 lateral mac on Abd.IV) (Fig. 4B).

Type-5 mes: 24–25 (and 1 uneven) /16, 6/5, 4, 6, 22, 0, 0 from head to Abd.VI (approximate numbers) (Fig. 2I for the head).

Trichobothria: 1/0, 0/0, 2, 3, 3, 0, 0 from head to Abd.VI.

S-chaetae (sens of types S1, S2, S3 and S4): 0/2, 1/1, 2, 3, 4, 3, 0 from head to Abd.VI. Possibly more on Abd.IV where type-5-like mes are often difficult to separate from S4.

Pseudopores: 1–2/1, 1/1, 1, 1, 1+2, 0, 0 from head to Abd.VI.

Chaetotaxy and pseudopores on head. As in Fig. 2I (dorsal side). No dorsal mac except the antenno-basal line of 5 mac (f1-f5); f0 as a minute thick uneven mic of type-6 between f1 chaetae; five ciliated clypeal mes and 1–2+1–2 pseudopores anteriorly to f1 (Fig. 2H). About 24 dorsal cephalic mes of type-5, subequal, short (Fig. 4A5). Cephalic trichobothria present dorsally at the middle of head with 1+1 mes internally near trichobothria, short and feebly ciliated (Fig. 2I, similar to Fig. 4A3). Ventrally, 4+4 post-labial mes smooth or very finely serrated along linea ventralis, and one mic of type-6 between G3 and H3 probably homologous with X (Fig. 2 in Chen and Christiansen 1993).

Chaetotaxy and pseudopores per tergite. (Figs 4B–F); values for type-5 mes are indicative). Th.II without mac; with a row of subequal spiny mes anteriorly and laterally, and several rows antero-laterally (type-2), 1+1 antero-lateral sens S1, 1+1 lateral sens S2 not close to S1, about 16+16 mes of type-5, and 1+1 pseudopores close to axis. Th.III without mac; with 1+1 antero-lateral sens S2, about 6+6 mes of type-5, and 1+1 pseudopores.

Abd.I without mac; with 1+1 lateral sens S1, about 5+5 mes of type-5 and 1+1 pseudopores.

Abd.II without mac; with 2+2 trichobothria, 6+6 modified mes around the trichobothria (type-4, Fig. 4C), 1+1 sens S2 (Fig. 4C) and 1+1sens S3 (Fig. 4C), about 4+4 mes of type-5, and 1+1 pseudopores. Abd.III with 3+3 trichobothria, 1+1 mac, 9+9 modified mes of type-4 on trichobothrial areas (3+3 near the internal trichobothria and 6+6 near the two external trichobothria, Fig. 4D), 3+3 sens in trichobothrial areas (1+1 S1 and 2+2 S3, Fig. 4D), about 6+6 mes of type-5, and 1+1 pseudopores. Abd.IV with 3+3 trichobothria, 2+2 mac, 4+4 modified mes of type-4 in the anterior trichobothrial area (none in the posterior trichobothrial area, Figs 4E and 6), 2+2 sens S3, 2+2 sens S4 near axis, about 22–23+22–23 mes, 2+2 sens S4 ahead pseudopores, in tandem with 2+2 short probably type-5 mes (Fig. 4F), 1+1 serrated mes of type-3 in tandem with 1+1 sens S3 posteriorly, and 3+3 pseudopores (1+1 in the middle of Abd.IV, 2+2 in the posterior margin of the tergite, behind a posterior row of 4+4 mes). Abd.V without pseudopore or mes of type-5; with 3+3 sens S3 and several short mac and mes.

Legs. Without scales. Trochanteral organ with 11–22 simple, straight, smooth chaetae arranged in V-form (Fig. 7C). Tibiotarsus chaetotaxy mostly composed of strong ciliated mes, with one thick smooth ventro-subapical chaeta on hind tibiotarsus. Each tibiotarsus with one tenent hair rather stout, apically spatulated, 4/5 as long as inner edge of claw; distal row of 9–10 serrated chaetae irregularly arranged on all tibiotarsi (Fig. 7D). Claw broad, not slender, with a weak or inconspicuous tunica; with one tooth at 40% of inner edge from the tip of the claw, a small dorsal tooth basally and a pair of inner basal teeth of unequal size, the outer one much larger than the inner one (Fig. 7D). Unguiculus pointed and broad, more than half as long as claw, lanceolate, with a strong outer tooth (Fig. 7D).

Ventral tube. Without scales. Anterior face with 2+2 long serrated chaetae (Fig. 7F). Posterior chaetae arranged typically for the genus, with L1 and L2 ciliated, L2 shorter than L1, M elongate and smooth, accompanied by 2+2 small peg-like microchaetae, and two long smooth distal chaetae; lateral flaps each with 2 small smooth mes (Fig. 7G).

Furca. Tenaculum with 4 teeth on each branch, anteriorly with strong, densely serrated, bent uneven chaeta (Fig. 7E). Furca with three types of chaetae (Fig. 7A) and 5 types of scales (Fig. 7B). Manubrium about 1.2 times as long as mucrodens. Dens about 2.3 times as long as mucro. Dorsal side of manubrium (Fig. 7H) with 2+2 pseudopores distally, and about 32–35 mes (fallen in most cases) arranged in two longitudinal stripes, including rather flexible and strongly ciliated mes and a few lateral ones slightly stronger, more straight, feebly serrated (Fig. 7A type-1), and baso-laterally 2+2 short serrated mes (Fig. 7A type-3); ventral side covered with oval scales (Fig. 7B type-5). Dens (Fig. 7H) elongate, dorsally with 2 rows of feathered scales (Fig. 7B type-1), 6 external and 5 internal, and 4 ciliated mes (Fig. 7A type-1) between two rows; proximal outer part of dens with 3 chaetae, two ciliated (Fig. 7A type-1) and the most external one smooth (Fig. 7A type-2); proximal inner part of dens with 2 slightly serrated mes (Fig. 7A1) close to dens-manubrium articulation; apical outer part of dens with one short serrated mes (Fig. 7A type-3); long dorso-distal feathered scales fallen in our specimens. Dens ventrally with oval scales (Fig. 7B types-4, 5), the distal internal one almost as long as mucro (Fig. 7B2, 3). Mucro straight, elongate, bidentate apically, with one minute external tooth almost at the level of the ante-apical normal tooth (Fig. 7I).

Genital plate. Male genital plate of the circinate type (sensu Christiansen 1958), with 6 genital mic and 15–16 circumgenital short, thin, smooth mes (Fig. 7K). Female genital plate with 2+2 mic (Fig. 7J).

in µm (from type specimen #PSUZC2011.SONG-001H, male).

From the name of the province “Songkhla” where this species was discovered.

Only known from the type locality.

Collected on guano in the dark zone of a cave developed in a karst covered with rainforest.

The new species is similar to Cyphoderus javanus Börner, 1906 and to Cyphoderus sumatranus Yoshii, 1987. The only detailed description of Cyphoderus javanus is that of Cyphoderus borneensis by Yoshii (1980, 1987), which was synonymized with Cyphoderus javanus by the same author in 1992. Cyphoderus songkhlaensis sp. n. differs from Cyphoderus borneensis as described by Yoshii in the following combination of characters: the posterior face of its ventral tube with chaetae L1 and L2 ciliated but M smooth (given however as ciliated in Yoshii 1980) (versus L1, L2, M all ciliated chaetae), anterior mac of ventral tube serrated versus smooth, spatulate versus blunt tenent hairs, no versus a few smooth basal chaetae on manubrium and claw with two inner teeth versus one inner tooth on claw.

Cyphoderus songkhlaensis sp. n. differs from Cyphoderus sumatranus by its ciliated clypeal chaetae (versus smooth in Cyphoderus sumatranus), the presence of one sublobal hair on outer maxillary lobe (versus none in Cyphoderus sumatranus) and the posterior face of its ventral tube with chaetae L1 and L2 ciliated but M smooth (versus L1, L2, M all ciliated chaetae). The new species is known from caves like Cyphoderus sumatranus, but Cyphoderus javanus has been reported from diverse habitats: termite nests, forest soil and caves.

Thailand: Sa Kaeo Province, Khao Chakan District, Tham Meud (Dark Cave) (13°39.541'N, 102°05.414'E), 73 m. above sea level, dark zone in cave, pitfall traps and Berlese extraction, S. Jantarit leg, 29 July 2012 (Sample #Sakaeo-SJ.001).

Holotype, male adult (#PSUZC2011.SAK-001H) and 11 paratypes (1 male and 10 of unknown gender) mounted on slides. Holotype and 5 paratypes at PSU (5 slides, 5 subadults, collection #PSUZC2011.SAK-001P-005P) and 6 paratypes at MNHN (6 slides, 1 males, 5 subadults).

Habitus thick, not troglomorphic, body length about 1.3 mm excluding antennae and furca. Furca well developed, about 2.4 times shorter than body. Body color white. Eyes absent, no ocular patch. Dense cover of scales on head, body and furca (ventrally on manubrium, both sides on dens); scales present on Ant.I–II dorsally, absent on legs and ventral tube. Types of chaetae as in Cyphoderus songkhlaensis sp. n.

Mouthparts. Outer maxillary lobe with one basal chaeta, a simple palp and one sublobal hair. Maxilla with 3-toothed capitulum and a complex of 5–6 pad-shaped lamellae not analyzed in detail. Mandible head stocky, asymmetrical with 5 (left) and 4 (right) teeth. Labial palp with 5 papillae (A–E) and 13 guards, as in Cyphoderus songkhlaensis sp. n.; hypostomal chaetae (H, h1, h2) present; 4 proximal chaetae. Labial basis formula m, e, l1, l2, with all chaetae smooth or indistinctly serrated, and l2 reduced to a minute but thick mic. Labral formula 4/5, 5, 4 with all chaetae smooth; two chaetae of the mid-row stronger and longer than others (similar to Cyphoderus songkhlaensis sp. n.); dorso-distal limit of primary granules with a deep central incision; labral edge without structure; ventro-distally, two asymmetrical combs with many teeth variously developed and two central tubules.

Antennae. About 1.7 times the length of the head, segmentations I:II:III:IV as 1:3.6:2.5:4.8. Sens and sens-like chaetae present on all antennal segments, of 10 morphological types like in Cyphoderus songkhlaensis sp. n. (Fig. 3A); type-3 mes rather long, apparently smooth under microscopic examination. Scales present dorsally on Ant.I and II (like Fig. 3A11). Ant.I dorsally like Fig. 3B, with scales and ciliated mes (type-1), except 3 basal mic (type-9); ventrally like Fig. 3C, with various types of chaetae (types-1, 2, 3, 5, 6 and 9). Ant.II like Fig. 3D, E, both dorsally and ventrally with numerous slender sens and chaetae (types-1, 3, 4, 5, 6, 7), with scales present dorso-basally; distally, 3–4 dorso-external swollen sens of type-7 and one ventro-external pseudopore. Ant.III like Fig. 3F, G, with various types of chaetae (1, 3, 4, 5, 6, 7, 9, 10) not analyzed in detail; dorso-externally, AIIIO like Fig. 3H, typical of Entomobryoidea, with sens 1 to 5 and 8 easily recognized, 2 and 3 being swollen sens of type-7; ventro-externally, one subapical pseudopore. Ant.IV like Fig. 3I, J, devoid of apical bulb, with various types of chaetae (including all types of sens except type-10); subapical organ present dorso-externally as a short and thick rod.

Dorsal chaetotaxy and pseudopores. Patterns and types of chaetae similar to those of Cyphoderus songkhlaensis sp. n. (Fig. 4). Dorsal chaetotaxy and pseudopore patterns (per side) as follows: macrochaetae: 0/0, 0/0, 0, 1, 2 from head to Abd.IV (excluding the antenno-basal lines on head and the 7–8+7-8 lateral mac on Abd.IV) (Fig. 4B). Type-5 mes: not analyzed in detail. Trichobothria: 1/0, 0/0, 2, 3, 3, 0, 0 from head to Abd.VI. S-chaetae (sens of types S1, S2, S3 and S4): 0/2, 1/1, 2, 3, 4, 3, 0 from head to Abd.VI, arranged as in Cyphoderus songkhlaensis sp. n. Probably more S-chaetae on Abd.IV where type-5-like mes are often difficult to separate from S4. Pseudopores: 1–2/1, 1/1, 1, 1, 1+2, 0, 0 from head to Abd.VI.

Ventral chaetotaxy of head. 4+4 post-labial mes smooth or very finely serrated along linea ventralis, and one mic between G3 and H3 probably homologous with X (Fig. 2 in Chen and Christiansen 1993).

Legs. Without scales. Trochanteral organ with 18 to 30 simple, straight, smooth chaetae arranged in V-form (Fig. 8A). Tibiotarsus chaetotaxy mostly composed of strong mes, with one thick smooth ventro-subapical chaeta on hind tibiotarsus. Each tibiotarsus with one tenent hair rather stout, apically spatulated, 3/4 to 4/5 as long as inner edge of claw; distal row of 9–10 serrated chaetae irregularly arranged on all tibiotarsi (Fig. 8B). Claw broad, not slender, without tunica; with 2 small teeth at 12% and 25% of inner edge from the tip of the claw, a small dorsal tooth basally and a pair of inner basal teeth of unequal size, the outer one much larger than the inner one (Fig. 8B). Unguiculus pointed and broad, more than a half as long as claw, lanceolate, with a strong outer tooth (Fig. 8B).

Ventral tube. Without scales. Anterior face with 2+2 long serrated chaetae (like Fig. 7F). Posterior chaetae arranged typically for the genus, with all 5 proximal chaetae (L1, L2 shorter than L1, M) ciliated, accompanied by 2+2 small peg-like microchaetae, and two long smooth distal chaetae; lateral flaps each with 2 short smooth mes (Fig. 8C).

Furca. Tenaculum with 4 teeth on each branch, and a strong, densely serrated, bent uneven chaeta anteriorly (like Fig. 7E). Furca with the same types of chaetae and scales as Cyphoderus songkhlaensis sp. n. (see Figs 7A, B). Manubrium slightly shorter or as long as mucrodens. Dens about 2.3 times as long as mucro. Dorsal side of manubrium (Fig. 8D) with 2+2 pseudopores distally, and about 32–35 mes (fallen in most cases) arranged in two longitudinal stripes, including rather flexible and strongly ciliated mes and a few lateral ones slightly stronger, more straight, feebly serrated (like Fig. 7A type-1), and baso-laterally 2+2 short serrated mes (like Fig. 7A type-3); ventral side covered with oval scales (like Fig. 7B5). Dens (Fig. 8D) elongate, dorsally with 2 rows of feathered scales (like Fig. 7B type-1), 6 external and 5 internal, and 4 ciliated mes (like Fig. 7A type-1) between the two rows; proximal outer part of dens with 3 chaetae, two ciliated (like Fig. 7A type-1) and the most external one smooth (like Fig. 7A type-2); proximal inner part of dens with 2 slightly serrated mes (like Fig. 7A type-1) close to the dens-manubrium articulation (like Fig. 7H); apical outer part of dens with a short serrated mes (like Fig. 7A type-3); long dorso-distal feathered scales fallen in our specimens. Dens ventrally with oval scales (like Fig. 7B types-4, 5), the two long distal ones fallen in our specimens. Mucro straight, elongate, bidentate apically, with an additional minute outer tooth almost at the level of the ante-apical normal tooth (Fig. 8E).

In µm (from type specimen #PSUZC2011.SAK-001H, male).

From the locality “Khao Chakan” district, in SaKaeo province, where this species is found.

Only known from type locality.

Abundant on guano in the dark zone of a karstic cave.