Tylopus namnonensis Likhitrakarn, 2025

Tylopus namnonensis Likhitrakarn , n. sp.

( Figs 4-6 View FIG View FIG View FIG )

urn:lsid:zoobank.org:act:53AC6D84-909A-4641-A7CF-0B5ED574A251

TYPE MATERIAL. — Holotype. Laos • ♂; Khammouane Province, Konglor, Tham Nam Non ; 175 m a.s.l.; 18°01’44”N, 104°41’26”E; 28.II.2023; J. Lips leg.; CUMZ-27205. GoogleMaps

Paratype. Laos • 1 ♀; same data as the holotype; CUMZ-27205 GoogleMaps .

ETYMOLOGY. — To emphasize Nam Non cave, the type locality, one of the biggest caves in Khammouane Province; adjective.

DIAGNOSIS. — This new species closely resembles T. dorsalis Likhitrakarn, Golovatch & Panha, 2016 , particularly in gonopod conformation. However, this new species is distinguished by the metaterga being roughly microgranulate (vs smooth), the distal position of process x on the solenophore (vs median), the pleurosternal carinae in ♂ extending to ring 13 (vs 16), and the tarsal brushes in ♂ present until ring 12 (vs 6).

DESCRIPTION

Length 22.5 mm (♂), 29.3 mm (♀), width of midbody proand metazona 2.2 and 2.8 mm (♂) or 2.7 and 3.5 mm (♀), respectively.

Coloration of live animals light brown ( Fig. 4B View FIG ), with contrasting dark brown to blackish collar covering both pro- and metazona, head, collum, rings 2 and 3 dark brown to blackish, antennae and epiproct light brown, antennomere 7 dark brown, paraterga, venter and legs yellowish brown; coloration of alcohol material after one year of preservation dark brown; paraterga, legs, antennae and epiproct light yellow-brown, antennomere 7 dark brown, head and collum brownish, following terga with a light brown triangle and a blackish collar covering both pro- and metazona ( Fig. 5 View FIG A-F), venter and a few basal podomeres light yellowish to pallid ( Fig. 5A, B View FIG , E-G).

Clypeolabral region and vertex rather densely setose, epicranial suture distinct. Antennae relatively short ( Fig. 5A, B View FIG ), reaching to body ring 3 when stretched dorsally (♂, ♀). In width, head <ring 3 <4 <collum <ring 2 <5 <6 <7-16 (♂, ♀), thereafter body gently and gradually tapering towards telson. Collum with three transverse rows of strong setae: 4+4 anterior, 1+ 1 intermediate, and 4+ 4 posterior; a small, lateral, setigerous incision near midway; caudal corner very broadly rounded, paraterga declined ventrad, not produced past rear tergal margin ( Fig. 5A, B View FIG ).

Tegument dull and shining, prozona finely shagreened, metaterga often roughly microgranulate and rugulose, leathery, surface below paraterga more delicately, but still sufficiently clearly microgranulate and rugulose ( Fig. 5 View FIG A-F). Postcollum metaterga with two transverse rows of rather long setae: 2 + 2 in anterior and 3+ 3 in posterior row, the latter often abraded, but then readily traceable as insertion points. Tergal setae long, strong, slender, about 1/4 metatergal length. Axial line well visible on metazona, traceable also on prozona. Paraterga strongly developed ( Fig. 5 View FIG A-G), especially so in ♂, set rather high (at upper 1/3 body height), slightly upturned, but lying below dorsum; anterior edge broadly rounded and narrowly bordered, fused to callus; caudal corner rather narrowly rounded, extending increasingly past rear tergal margin, especially well curved mesad on rings 16-19, posterior edge oblique ( Fig. 5F, G View FIG ); paraterga very thin blunt blades in lateral view, a little thicker only on pore-bearing rings ( Fig. 5D View FIG ). Calluses on paraterga delimited by a sulcus both dorsally and ventrally. Paraterga 2 broad, horizontal, anterior edge angular, lateral edge with three evident incisions: two in anterior 1/3, one at midway, and the smallest one near a very broadly rounded caudal corner. Paraterga 3 and 4 each with two small incisions at lateral edge ( Fig. 5A View FIG ), one in anterior 1/3, the other at posterior 1/3. Following paraterga each with one evident lateral incision in anterior 1/3 ( Fig. 5C View FIG ). Ozopores evident, lateral, lying in an ovoid groove at about 1/3 metatergal length in front of posterior edge of metaterga ( Fig. 5B, D View FIG ). Transverse sulcus usually distinct ( Fig. 5A, C, F View FIG ), slightly incomplete on ring 19, complete and clearly visible on metaterga 5-18, narrow, deep, reaching the bases of paraterga, ribbed at bottom. Stricture between pro- and metazona wide, deep, ribbed at bottom down to base of paraterga ( Fig. 5A, C, F View FIG ). Pleurosternal carinae complete crests on rings 2-4 (♂, ♀), clearly increasing in size on rings 5-7, thereafter broken into an anterior small bulge and a small and sharp caudal tooth, both growing increasingly reduced until ring 13, thereafter missing (♂) ( Fig. 5B, D, E View FIG ), or increasingly reduced and remaining only a small caudal tooth until ring 8, thereafter missing (♀). Epiproct ( Fig. 5 View FIG EG) conical, flattened dorsoventrally, subtruncate, with two evident apical papillae directed caudally, both pointed at tip; pre-apical papillae small, but evident, lying close to tip. Hypoproct subtrapeziform ( Fig. 5G View FIG ), small setiferous knobs at caudal edge well-separated and evident.

Sterna sparsely setose, without modifications ( Fig. 5G View FIG ); cross-impressions shallow; a large, central, slightly bifid, setose lobe between ♂ coxae 4 ( Fig. 5H, I View FIG ). Legs long and slender, midbody ones c. 1.2-1.4 (♂) or 0.9-1.1 times (♀) as long as body height; prefemora not swollen, legs on rings 6-8 each with a small adenostyle on postfemur and tibia; legs of rings 9-16 each with a small adenostyle on femur, postfemur, tibia and tarsus ( Fig. 6E View FIG ); telopodites particularly densely setose ventrally ( Fig. 6E View FIG ), tarsal brushes present until ring 12.

Gonopods rather simple ( Fig. 6 View FIG A-D). Prefemorite (pfe) densely setose, about 1/3 as long as femorite + “postfemoral” part. Femorite (fe) slightly curved and stout, with an evident mesal groove and a clear distolateral sulcus demarcating a postfemoral part; lobe l simple ( Fig. 6B, C View FIG ); process h rather short, mediodorsal, flattened, tip rounded and with a small notch ( Fig. 6B, C View FIG ); solenophore (sph) long and slender, typically coiled, expanded distad, flattened and evidently bifid, with process x being elongated, apically rounded and directed forward ( Fig. 6A, C, D View FIG ).

REMARKS

The specimens were collected inside a cave ( Fig. 4A View FIG ), around 500 meters away from the entrance. In the wet season, an underground river takes up all of the gallery. Big trees and a lot of wood remains are carried inside. The specimens were collected on wood debris.Despite formally coming from a cave, this new species seems to be nothing more than a trogloxene.