Stemmiulus ongot 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 : 13-14

Stemmiulus ongot Nzoko Fiemapong & VandenSpiegel sp. n. Figure 1

Type material.

Holotype ♂ (MRAC 22734), Cameroon, Center Region, Ongot disturbed Forest, N 03°51', E 011°25', ca 810 m a.s.l., 30.I.2015, leg A. R. Nzoko Fiemapong.

Paratype: 1 ♂ (SEM, lost).

Etymology.

The species is named after Ongot, the type locality.

Diagnosis.

Stemmiulus ongot sp. n. is characterized by the first six pairs of male legs being densely setose, the lateral projection of the subterminal lobe of the gonopodal angiocoxites relatively short (Fig. 1H, I), the apical parts of the angiocoxite densely setose (Fig. 1H, I) and, especially, by the peculiar second pair of male legs (Fig. 1 E–G), the telopodites of which are 2-segmented, the proximal segment being expanded apicolaterally and bearing a lateral fringe of setae.

Description.

Holotype: adult male, ca 15 mm in length, 1.7 mm in maximum diameter, body with 43 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 (Fig. 1A); ommatidia 2+2, anterior ones slightly smaller; antennae long and setose, apices reaching fourth body ring. Gnathochilarium concave, stipes densely and uniformly porose.

Collum without any ornamentation. Body rings ovoid in transverse section, height/width ratio of midbody rings ca 0.41; no legless body rings in front of telson. Prozonites smooth, metazonites with oblique transverse striae.

First six pairs of legs covered with numerous plumose setae. First pair unmodified, tarsi with a fringe of ventral setae in basal 2/3, but forming no true brush, coxae, femora, postfemora and tibiae each with an apical cluster of prominently enlarged spatulate setae (Fig. 1B, C).

Second pair of legs with coxa enlarged and elongated, anterior face with traces of segmentation, setose over entire anterior surface, glabrous on posterior surface; laterally each produced into a prominent, elongated, conical projection (Fig. 1F, G) and with an apicomesal cluster of elongated setae. Telopodite 2-segmented, proximal segment with an apicolateral projection bearing a lateral fringe of setae, an apicomedial cluster of setae and a ventromedial cluster of long setae (Fig. 1F, G); distal segment long and slender, curved mesad, with a basal cluster of setae and plumose distally (Fig. 1G).

Pair 7 similar to following ones, without specialized setae.

Gonopod structure (Fig. 1H, I) typical of the genus, angiocoxite with a small, projecting, subapicolateral process. Apex of colpocoxite simple, with neither a lobe nor a projection surrounding the flagella (Fig. 1H).

Paragonopods small and 3-segmented, median segment carrying a short series of long setae on medial side, distal segment minute, conical, with a few apical setae (Fig. 1D).

Relationships.

By the relative complexity of the gonopodal structure S. ongot sp. n is closely related to S. albicephalus from Tanzania, but the striations of the lateral sides of prozonae remind of those observed in S. infuscatus from Cameroon. Nevertheless, the males of these species can easily be distinguished by the structure of the lateral projection of the colpocoxite which is small and apically setose in S. ongot sp. n., and relatively elongate without setae in S. albicephalus and S. infuscatus . On the other hand, the conformation of the second pair of legs of S. ongot sp. n. is unique in the entire genus Stemmiulus .

Distribution.

Known only from the type locality.