Coxobolellus serratoligulatus, Pimvichai & Enghoff & Backeljau, 2022

Pimvichai, Piyatida, Enghoff, Henrik & Backeljau, Thierry, 2022, Two new millipede species of the genus Coxobolellus Pimvichai, Enghoff, Panha & Backeljau, 2020 (Diplopoda, Spirobolida, Pseudospirobolellidae), ZooKeys 1128, pp. 171-190 : 171

Coxobolellus serratoligulatus sp. nov.

Figs 3 , 4 , 5

Material studied.

Holotype ♂ (CUMZ-D00154-1), Thailand, Uttaradit Province, Thong Saen Khan District, Tham Chan ; 17°35'4"N, 100°25'10"E; 230 m a.s.l.; 31 July 2020; P. Pimvichai, P. Prasankok and S. Saratan leg. Paratypes. 2 ♀♀; same data as holotype (CUMZ-D00154-2) .

Etymology.

The species epithet is a Latin adjective meaning "with a serrated tongue" and refers to the characteristic process of the posterior gonopod.

Diagnosis.

Anterior gonopods with high coxae, apically obliquely truncated (Fig. 3A, D ). Similar in this respect to C. albiceps . Differing from all other species in the genus by having the posterior gonopod with a massive, broad, flattened, serrate process protruding from the mesal surface, forming a tongue-like process (Fig. 3C, F-H ), whereas in the other 11 Coxobolellus species the telopodital part of the posterior gonopod has no distinct tongue-like process.

Description.

Adult male with 54 podous rings. Length ca 5 cm, diameter ca 4.0 mm. Adult females with 51-53 podous rings. Length ca 5 cm, diameter ca 3.9-4.1 mm.

Colour. Living animal dark green except for dark brown antennae and legs (Fig. 4B ).

Anterior gonopods (Fig. 3A, B, D, E ) with high coxae, apically obliquely truncated, mesal margins straight, posterior surface with relatively high ridge laterally for accommodation of telopodite. Telopodite (at) projecting over anterior gonopod coxa (cx), subapically strongly constricted, apically forming a big triangular process with pointed tip and a pigmented brown node (Fig. 3B, E , unlabeled arrow).

Posterior gonopods (Fig. 3C, F-H ) very simple, rounded, with long, smooth coxal part (pcx); telopodital part (pt) fairly long, curving mesad, ending in a rounded lobe, forming a canopy, with a large, broad, flattened, serrate process protruding from mesal surface, forming a tongue-like process (Fig. 3H , unlabeled arrow).

Female vulvae (Fig. 3I ): valves prominent, of equal size.

DNA barcodes.

The GenBank accession numbers are:

Holotype CUMZ-D00154-1: COI = OP580100; 16S rRNA = OP580515.

Paratype CUMZ-D00154: COI = OP580099, 16S rRNA = OP580514.

Habitat.

Found under leaf litter.

Distribution.

Known only from the type locality in Uttaradit Province, Thailand (Fig. 5 ).

Figures

Figure 3. Coxobolellus serratoligulatus sp. nov., holotype, gonopods (CUMZ-D 00154 - 1) A, D anterior gonopod, anterior view B, E anterior gonopod, posterior view, unlabeled arrows indicate a pigmented brown node C, F left posterior gonopod G SEM, left posterior gonopod, posterior-mesal view H SEM, tip of posterior gonopod, posterior-lateral view, unlabeled arrow indicates the tongue-like process I SEM, left female vulva, posterior-mesal view. at = anterior gonopod telopodite; cx = coxa; oeg = opening of efferent groove; op = operculum of vulva; pcx = coxal part of the posterior gonopod telopodite; pt = telopodital part of the posterior gonopod telopodite.

Figure 4. Live Coxobolellus species from Thailand A C. saratani sp. nov., male (paratype, CUMZ-D 00153 - 2) B C. serratoligulatus sp. nov., male (holotype, CUMZ-D 00154 - 1).

Figure 5. Distribution of the species of Coxobolellus in Thailand. Droplets vary in size to improve readability.