Touranella chenla Likhitrakarn, 2025

Likhitrakarn, Natdanai, Golovatch, Sergei I., Inkhavilay, Khamla, Panha, Somsak & Sutcharit, Chirasak, 2025, Taxonomic review of the millipede genus Touranella Attems, 1937, with a redescription of the type species, T. gracilis Attems, 1937, and descriptions of three new species from Laos (Diplopoda, Polydesmida, Paradoxosomatidae), ZooKeys 1238, pp. 183-208 : 183-208

publication ID	https://doi.org/10.3897/zookeys.1238.147550
publication LSID	lsid:zoobank.org:pub:1DD6E6F9-37AE-4DA0-AF62-64AD586F6F9A
DOI	https://doi.org/10.5281/zenodo.15442240
persistent identifier	https://treatment.plazi.org/id/97B290B7-A139-5D3E-BDE6-D5AA21F7EFF7
treatment provided by	ZooKeys by Pensoft
scientific name	Touranella chenla Likhitrakarn
status	sp. nov.

Treatment

Touranella chenla Likhitrakarn sp. nov.

Figs 4 View Figure 4 , 5 View Figure 5 , 6 View Figure 6

Type material.

Holotype • ♂ ( CUMZ - PD 0031 ), Laos, Champasak Province, Pakse District, Vat Phou , 107 m, 14°50'52.9"N, 105°49'38.8"E, 23.7.2013, leg. Chirasak Sutcharit GoogleMaps .

Diagnosis.

The new species seems to be particularly similar to T. champasak from Bolaven Plateau, Laos, especially in gonopodal structure. Both species share a strongly reduced gonopodal femorite devoid of a femoral process and a distally slightly twisted solenophore (Figs 5 View Figure 5 , 6 View Figure 6 ). However, the new species differs from T. champasak by having a long, acute process d located around the mid-length of a more clearly erect and thicker solenophore (Figs 5 View Figure 5 , 6 View Figure 6 ). Additionally, pleurosternal carinae are complete crests with sharp caudal denticles extending beyond the rear tergal margin only on rings 2 and 3, reduced to a rounded caudal crest on rings 4 and 5, and absent thereafter (Fig. 4 C, E View Figure 4 ) (vs absent on rings 18–19). Moreover, ♂ tarsal brushes are present until ring 8 (vs until ring 16).

Description.

Length 15.2 mm, width of midbody pro- and metazona 1.1 and 1.3 mm, respectively (♂). Coloration of live animals dark brown (Fig. 4 A View Figure 4 ); legs pale orange, venter and a few basal podomeres pale brown to yellow brown. Coloration in alcohol after 11 years of preservation faded to pale brown; antennae and epiproct pale brown to pallid, venter and podomeres pallid (Fig. 4 B – J View Figure 4 ).

Clypeolabral region and vertex sparsely setose, epicranial suture distinct. Antennae long (Fig. 4 A View Figure 4 ), reaching until ring 5 when stretched dorsally. In width, ring 4 <3 <2 <collum <ring 5 <6 <7 <head <8–17, thereafter body gently and gradually tapering towards telson. Collum with three transverse rows of setae: 3 + 3 anterior, 2 + 2 intermediate, and 3 + 3 posterior; caudal corner very narrowly rounded, slightly declined ventrally, not produced past rear tergal margin (Fig. 4 A – C View Figure 4 ).

Tegument smooth and shining, prozona finely shagreened, metaterga nearly smooth, faintly rugulose and leathery (Fig. 4 B – F, H View Figure 4 ). Postcollum metaterga each with two transverse rows of setae: 2 + 2 anterior and 2 + 2 posterior, traceable at least as insertion points when setae broken off. Tergal setae simple, slender, short, ~ 1 / 3 metatergal length (Fig. 4 F View Figure 4 ). Axial line well visible on metazona, traceable also on prozona.

Paraterga weak (Fig. 4 A – F, H View Figure 4 ), lying at ~ 1 / 2 midbody height, slightly upturned, anterior edge rounded and narrowly bordered; caudal corner very narrowly rounded on rings 2–4, not produced past rear tergal margin; almost missing on following rings; pore-bearing rings with evident lateral bulges (Fig. 4 B, D View Figure 4 ). Ozopores evident, lateral, each lying in an ovoid groove at ~ 1 / 3 metatergal length in front of posterior edge of metaterga (Fig. 4 C, E, H View Figure 4 ). Transverse metatergal sulci complete on rings 5–16, incomplete on ring 17, very narrow, shallow, not reaching the bases of paraterga, at most faintly beaded at bottom (Fig. 4 B – F, H View Figure 4 ). Stricture between pro- and metazona wide, deep, clearly ribbed at bottom down to base of paraterga (Fig. 4 B – F, H View Figure 4 ). Pleurosternal carinae complete crests with a very sharp median tooth on rings 2 and 3, reduced to a rounded caudal crest on rings 4 and 5, thereafter missing (Fig. 4 C, E, H View Figure 4 ).

Epiproct (Fig. 4 F – H View Figure 4 ) conical, flattened dorsoventrally, with two small, rounded, apical papillae; tip subtruncate; lateral pre-apical papillae very small, lying close to tip. Hypoproct roundly subtriangular, setigerous knobs at caudal edge small and well-separated (Fig. 4 G View Figure 4 ).

Sterna sparsely setose, without modifications; an entire, high, rounded, linguiform, setose sternal lobe between ♂ coxae 4 (Fig. 4 I, J View Figure 4 ). Legs long, midbody legs 1.2–1.4 × as long as body height, prefemora without modifications, ♂ tarsal brushes present until ring 8.

Gonopods simple, slim and suberect (Figs 5 View Figure 5 , 6 View Figure 6 ). Coxite slightly curved caudad, densely setose distodorsally (Figs 5 A, B View Figure 5 , 6 A, B, D View Figure 6 ). Prefemoral part (= prefemorite, pfe) as usual, densely setose, ~ 3.5 × shorter than acropodite (femoral + postfemoral parts) (Figs 5 A, B View Figure 5 , 6 A – C View Figure 6 ). Femorite (fe) short, with a strong, long, flagelliform solenomere (sl) twisted distad and with a strong, oblique, lateral sulcus demarcating a postfemoral part (Figs 5 A, B View Figure 5 , 6 A – C View Figure 6 ). Solenophore (sph) long, slightly twisted distad, sheathing most of solenomere (sl), slightly curved caudad (Figs 5 A, B View Figure 5 , 6 A – D View Figure 6 ). Solenophore consisting of a well-developed lamina lateralis (ll) and a smaller lamina medialis (lm) (Figs 5 B View Figure 5 , 6 B, C View Figure 6 ). Tip of lamina medialis subtruncate (Figs 5 B View Figure 5 , 6 B View Figure 6 ), tip of lamina lateralis subrectangular with a long, slender, curved, nearly pointed process d (d), this rising distal to lamina lateralis (Figs 5 A, B View Figure 5 , 6 A – D View Figure 6 ). Both supporting a long and flagelliform solenomere.

Distribution.

Known only from the type locality, apparently endemic to the southern part of Laos.

Etymology.

The species epithet chenla refers to the ancient kingdom of Chenla, a powerful kingdom that thrived from approximately 550 to 802 AD across the present-day territories of Thailand, Laos, Cambodia, and Vietnam. The naming also reflects the historical connection between the Chenla era and the construction of the Vat Phou temple complex in Champasak Province, Laos, where the species was discovered ( Wikipedia 2025 a, b). This new species so named pays tribute to the rich cultural and historical heritage of the region.

Remarks.

The newly described species was discovered in the vicinity of Vat Phou, Champasak Province, Laos. This ruined Khmer Hindu temple complex, recognized as a UNESCO World Heritage Site, is situated amidst the lush landscapes of Southeast Asia, providing an intriguing backdrop for biodiversity exploration.