Sellanucheza laotica sp. nov.
Figs 6, 7, 8
Type material.
• Holotype ♂ (CUMZ -11647), Laos, Khammouane Province, Nong Ping, Tham Nguen Mai, 230 m a. s. l., 17°22'14"N, 105°53'37"E, 24. 02. 2016, leg. J. Lips. • Paratypes 3 ♂, 4 ♀ (CUMZ -11647), same locality, together with holotype.
Diagnosis.
The new species is distinguished from all known congeners by the following combination of characters. Somatically, it differs from the Chinese S. tenebra, S. typica and S. jaegeri by the strongly developed paraterga on midbody rings (vs paraterga virtually absent or very poorly developed). From the large Vietnamese S. grandis and S. hoffmani, it is separated by the significantly smaller body size and the uniform, light yellowish to pallid coloration. A unique apomorphy seems to be the presence of well-developed ventroposterior tubercles on sterna near coxae, starting with ring 6. The gonopods are characteristic in the relatively short solenophore showing a truncate, subquadrate distal margin and an acute ventral angle. In addition, the species differs from S. variata and S. jaegeri by process pb being short, blunt and suberect (vs long, slender and acute or subunciform), and by the short, relatively stout solenomere which is subequal in length to the solenophore (vs long and flagelliform in other congeners).
Description.
Length 11.3–13.6 (♂) or 12.1–13.2 mm (♀), width of midbody pro- and metazona 0.8–1.2 and 1.2–1.4 mm (♂) or 0.9–1.2 and 1.2–1.4 mm (♀), respectively.
Coloration of alcohol material after nine years of preservation uniform light yellowish to pallid; antennae and legs slightly paler (Fig. 6 A – I).
Clypeolabral region and vertex sparsely setose, epicranial suture distinct. Antennae moderately long (Fig. 6 A, B), reaching body ring 4 (♂) or 3 (♀) when stretched dorsally. In width, head <ring 3 <4 <collum <ring 5 <6 <2 <7–17 (♂, ♀) (Fig. 6 A); thereafter body gently and gradually tapering. Collum with three transverse rows of setae: 4 + 4 anterior, 2 + 2 intermediate and 3 + 3 posterior; lateral margin with a small incision laterally in posterior half; posterior corner of paraterga very narrowly rounded, slightly declined ventrad, not extending past tergal margin (Fig. 6 A, B).
Tegument smooth and shining (Fig. 6 A – G), prozona very finely shagreened, metaterga smooth and leathery; surface below paraterga finely microgranulate (Fig. 6 B, D, E). Postcollum metaterga with two transverse rows of setae: 3 + 3 in anterior (pre-sulcus) and 3 + 3 in posterior (post-sulcus) row. Tergal setae long, strong, slender, ca 1 / 3 metatergal length. Axial line faint, barely traceable on metaterga. Paraterga strongly developed (Fig. 6 A – G), especially so in ♂, set at ca 1 / 3 midbody height, slightly upturned, but all lying below dorsum; shoulders well-developed, mostly rounded; posterior corner almost completely to very broadly rounded, all extending past tergal margin, posterior edge slightly concave, bent ventrad on rings 18 and 19 (Fig. 6 F).
Paraterga 2 broad, anterior edge angular, lateral edge with two evident incisions in anterior half; posterior edge oblique (Fig. 6 A, B). Lateral edges of paraterga 3 and 4 with two evident incisions: one in anterior 1 / 3, the other at midway (Fig. 6 A). Following paraterga with three evident incisions: largest one in anterior 1 / 3, one at midway, and another near posterior corner (Fig. 6 A, C). Paraterga thin blunt blades in lateral view, slightly thicker only on pore-bearing rings (Fig. 6 B, D, E). Calluses on paraterga demarcated by sulci only dorsally. Ozopores evident, lateral, each lying in an ovoid groove at ca 1 / 4 in front of posterior corner (Fig. 6 D, E). Transverse sulcus usually distinct, slightly incomplete on ring 4, complete and clearly visible on metaterga 5–18, usually narrow, shallow (Fig. 6 A, C, F), superficial (due to coarse texture), not reaching bases of paraterga, slightly better developed in ♀. Stricture between pro- and metazona narrow, ribbed at bottom down to base of paraterga (Fig. 6 A, C, F). Pleurosternal carinae complete crests, each usually with a sharp posterior tooth until ring 17, crests bulged anteriorly and with a small sharp posterior tooth each on rings 18 and 19 (♂, ♀) (Fig. 6 B, D, E).
Epiproct (Fig. 6 E – G) conical, rounded dorsoventrally, with two small apical papillae; tip subtruncate; pre-apical papillae evident, lying close to tip (Fig. 6 F). Hypoproct roundly subtrapeziform (Fig. 6 G), setiferous knobs at posterior edge well-separated and evident.
Sterna sparsely setose, cross-impressions shallow; starting on ring 6 with a pair of well-developed, ventroposterior tubercles near each coxa; a large, central, cordiform, densely setose lobe between ♂ coxae 4 (Fig. 6 H, I). Legs moderately long and slender, midbody legs ca 1.0–1.3 (♂) or 0.9–1.2 × (♀) as long as body height, ♂ prefemora without modifications, tarsal brushes present until ♂ legs 4.
Gonopods (Figs 7, 8) simple. Coxite long, slender, cylindrical, slightly curved posteriorly, densely setose distodorsally. Prefemorite (pfe) densely setose, as usual, ovoid, elongate, ca 1 / 3–1 / 4 length of acropodite (Figs 7 A, 7 B, 7 F, 7 G, 8 A – C). Femorite (fe) long, slender, curved (Fig. 7 B, F, G, 8 A, B); distal part supplied with a short, blunt, suberect process pb (Figs 7 B – I, 8 B, 8 C) and a short, slender, spiniform, slightly curved, mesal process pa (Figs 7 A, 7 C – G, 7 I, 8 A – D). Solenophore (sph) relatively short, supporting solenomere (sl), distal margin truncate, subquadrate, with an acute ventral angle (Figs 7 C – F, 8 C). Solenomere short, subequal in length to solenophore, relatively stout, tip acute and slightly projecting distad (Figs 7 A, 7 E – I, 8 A – D).
Remarks.
Sellanucheza laotica sp. nov. represents the first record of the genus from a limestone cave in Khammouane Province, Laos. The distinct pallid coloration strongly suggests a troglobiomorphic adaptation to its subterranean existence, a characteristic frequently observed in other cave-dwelling millipedes within the region (Likhitrakarn et al. 2017, 2021, 2022, 2024; Liu and Wynne 2019; Golovatch and Liu 2020). The new species appears to be narrowly endemic to its karst cave systems in northeastern Laos.
Etymology.
The specific epithet is a Latin adjective referring to Laos, the country of origin where the type material was collected.
Publication Date: 2026-06-23