Nepalella Shear, 1979

Likhitrakarn, Natdanai, Golovatch, Sergei I. & Panha, Somsak, 2022, The Oriental millipede genus Nepalella Shear, 1979, with the description of a new species from Thailand and an updated key (Diplopoda, Chordeumatida, Megalotylidae), ZooKeys 1084, pp. 183-199 : 183

Genus Nepalella Shear, 1979

Nepalella Shear, 1979: 126, D, K.

Nepalella - Golovatch 1983: 126, D; Shear 1987: 237, D; 1999: 2, D; 2002: 65, D; Mauriès 1988: 26, D; Golovatch et al. 2006a: 83, M, K; 2006b: 84, M; Liu et al. 2017b: 455, M, K; Golovatch and Liu 2020, L, M.

Diagnosis.

The millipede genus Nepalella Shear, 1979 as a member of the family Megalotylidae is mainly distinguished from Megalotyla , the only other component genus of the family, by the anterior gonopods still showing weakly developed coxites placed on a relatively small, central sternum (versus coxites completely absent from a larger sternal plate in Megalotyla ) ( Enghoff et al. 2015).

Brief description.

Body medium- to large-sized (ca 10-42 mm long, ca 0.64-3.2 mm wide), with 28 or 30 segments. Mentum not divided. Paraterga either distinct keels or small bulges, or missing. ♂ legs 3-7 often distinctly and increasingly crassate, some with femoral knobs. ♂ legs 10 with coxal glands, but ♂ legs 11 either with or without coxal glands. Female genitalia often species-characteristic.

Anterior gonopods strongly reduced, consisting of only a small sternal (coxosternal?) plate with a median lamellate process and two lateral spikes (coxites). Posterior gonopods with large and bipartite coxites, divisions being clearly visible when seen in anterior view, either branching or simple; lateral division often in the form of a broad, flat plate turned with its axis parallel to body midline. Posteriorly, at least one branch covered with fine cuticular fimbriae present, entire posterior surface of coxite may appear densely hairy. Telopodites may be quite small, typically reduced to a prefemur and a femur, the latter turned sharply dorsad.

Type species.

Nepalella khumbua Shear, 1979, by original designation.

Other species included.

Nepalella birmanica Mauriès, 1988, N. caeca Shear, 1999, N. deharvengi Mauriès, 1988, N. gairiensis Mauriès, 1988, N. grandis Golovatch, Geoffroy & Mauriès, 2006, N. grandoides Golovatch, Geoffroy & Mauriès, 2006, N. griswoldi Shear, 2002, N. gunsa Shear, 1987, N. inthanonae Mauriès, 1988, N. jaljalae Mauriès, 1988, N. jinfoshan Liu, in Liu et al. 2017b, N. kavanaughi Shear, 2002, N. lobata Liu in Liu et al. 2017b, N. magna Shear, 2002, N. marmorata Golovatch, Geoffroy & Mauriès, 2006, N. pallida Mauriès, 1988, N. phulcokia Mauriès, 1988, N. pianma Shear, 2002, N. ringmoensis Mauriès, 1988, N. taiensis Mauriès, 1988, N. taplejunga Shear, 1987, N. thodunga Shear, 1979, N. tragsindola Mauriès, 1988, N. troglodytes Liu, in Liu et al. 2017b, N. vietnamica Golovatch, 1983, N. wangi Liu, in Liu et al. 2017b, N. siamensis sp. nov.

Distribution.

Nepal, southern China, Myanmar, northern and southeastern Thailand, and northern Vietnam (Fig. 1 ).

A brief historical account.

The genus Nepalella was first established by Shear (1979), based on two new species from Nepal, including characters of the female vulvae (= cyphopods) added to both descriptions. Golovatch (1983) described a new species from northern Vietnam and, together with Megalotyla , assigned it to the family Megalotylidae . Shear (1987) added further two new species from Nepal, this time using only male specimens for descriptions.

Mauriès (1988) published ten new Nepalella species from Nepal, Myanmar or Thailand, including descriptions of female genitalia that followed Shear’s (1979) pattern. Although the morphological differences in the vulvae were often found species-specific, Mauriès (1988) preferred not to describe new species based solely on female material.

Shear (1999, 2002) reviewed Nepalella and described five new species from China, including N. magna , the first to be named based on four female specimens alone. That species was particularly large in size, showed morphologically distinctive vulvae, and found coexisting in syntopy with both N. griswoldi and Vieteuma longi Shear, 2002, the latter taxon another chordeumatidan genus and family ( Shear 2002).

Golovatch et al. (2006a, b) described a further three Nepalella from Chinese caves and provided a key to all species then known in the genus. More recently, Liu et al. (2017b) published four new species and two new records of Nepalella , including a key to, and a distribution map for, all 12 species of Nepalella from China. This latter study also pioneered barcoding in Nepalella , providing the first molecular-based phylogeny of a chordeumatidan genus outside Europe.

Figures

Figure 1. Distributions of Nepalella species (28 species), arranged from northwest to southeast 1 N. phulcokia Mauries, 1988 2 N. gairiensis Mauries, 1988 3 N. thodunga Shear, 1979 4 N. deharvengi Mauries, 1988 5 N. ringmoensis Mauries, 1988 6 N. tragsindola Mauries, 1988 7 N. khumbua Shear, 1979 8 N. jaljalae Mauries, 1988 9 N. taplejunga Shear, 1987 10 N. gunsa Shear, 1987 11 N. marmorata Golovatch, Geoffroy & Mauries, 2006 12 N. grandoides Golovatch, Geoffroy & Mauries, 2006 13 N. lobata Liu, in Liu et al. 2017 14 N. jinfoshan Liu, in Liu et al. 2017 15 N. wangi Liu, in Liu et al. 2017 16 N. grandis Golovatch, Geoffroy & Mauries, 2006 17 N. troglodytes Liu, in Liu et al. 2017 18 N. caeca Shear, 1999 19 N. kavanaughi Shear, 2002 20 N. pianma Shear, 2002 21 N. pallida Mauries, 1988 22 N. birmanica Mauries, 1988 23 N. magna Shear, 2002 24 N. griswoldi Shear, 2002 25 N. vietnamica Golovatch, 1983 26 N. taiensis Mauries, 1988 27 N. inthanonae Mauries, 1988 28 N. siamensis sp. nov.