Stemmiulus mbalmayoensis Nzoko Fiemapong & VandenSpiegel

Fiemapong, Armand Richard Nzoko, Masse, Paul Serge Mbenoun, Tamesse, Joseph Lebel, Golovatch, Sergei Ilyich & VandenSpiegel, Didier, 2017, The millipede genus Stemmiulus Gervais, 1844 in Cameroon, with descriptions of three new species (Diplopoda, Stemmiulida, Stemmiulidae), ZooKeys 708, pp. 11-23 : 17

Stemmiulus mbalmayoensis Nzoko Fiemapong & VandenSpiegel sp. n. Figure 3

Type material.

Holotype ♂ (MRAC 22730), Cameroon, Center Region Zamakoe near Mbalmayo Reserve Forest, N 03°33', E 011°31', 815 m a.s.l., forest, 19.IV.2014, leg. A. R. Nzoko Fiemapong.

Paratype: 1 ♂ (SEM, MRAC 22731), same locality, pitfall trap, 18.IV.2015, leg. A. R. Nzoko Fiemapong.

Etymology.

The species is named after the Mbalmayo Reserve Forest, the type locality.

Diagnosis.

A species close to the previous new one and to S. beroni by its external characters, but is easily distinguished by the structure of the colpocoxite whose apical part is axe-shaped.

Description.

Holotype: adult male, ca 20 mm in length, 1.8 mm in maximum diameter, body with 46 rings. Head and collum dark brown, other body rings brown with a light axial dorsal stripe, legs and antennae yellowish.

Head typical in shape, beset with numerous simple macrosetae as in previous species; ommatidia 2+2, posterior ommatidia slightly larger than anterior ones. Antennae reaching the fourth body ring, and covered with minute setae.

Gnathochilarium concave, without special modification, stipes densely and uniformly porose, pores surrounded by a field of setae. Collum with a single fringe at anterior edge, this being best visible laterally. Body rings ovoid (height/width ratio of midbody rings ca 0.38), metazonites with transverse oblique striae better visible at pleurotergal margin. Striations on prozonites more weakly developed than on metazonites. Annal valves beset with numerous setae.

First pair of legs and legs 3 to 6 as in S. uncus (Fig. 3A).

Second pair of legs with enlarged and subquadrate coxae (Fig. 3B, C), anterior surface with traces of segmentation, a few setae on entire anterior surface, posterior surface glabrous. Telopodite 2-segmented, proximal segment longer, about twice as long as distal one, curved ventrad, with a ventromedial cluster of long setae (Fig. 3B, C). Distal segment more slender, curved mesad, with an apical row of short setae.

Gonopods (Fig. 3 D–F) relatively simple in structure, angiocoxite with a well prominent constriction in subapical part, apical part forming a setose corolla. Colpocoxite ending up in an axe-shaped structure slightly protruding from angiocoxite.

Paragonopods small, 3-segmented, quite similar to those in most of the African congeners.

Female unknown.

Relationships.

Most of the peripheral characters and especially the simple gonopods seem to bring S. mbalmayoensis sp. n. close to S. uncus sp. n., S. beroni and S. pullulus . Nevertheless, the males of all these species can easily be distinguished by the structure of the colpocoxite, in which the apical part is axe-shaped in S. mbalmayoyensis sp. n., pointed and unciform in S. uncus sp. n., pointed and straight in S. beroni , but with a rounded tip in S. pullulus .

Distribution.

Known only from the type locality.