Diaphorodesmoides lamottei, VandenSpiegel, Didier, Golovatch, Sergei I. & Mauries, Jean-Paul, 2016

VandenSpiegel, Didier, Golovatch, Sergei I. & Mauries, Jean-Paul, 2016, Review of the western African millipede genus Diaphorodesmus Silvestri, 1896 (Diplopoda, Polydesmida, Chelodesmidae), with the description of a similar, but new monotypic genus from Cameroon, ZooKeys 600, pp. 7-24 : 12-17

Taxon classification Animalia Polydesmida Chelodesmidae

Diaphorodesmoides lamottei sp. n. Figs 8, 9, 10, 11, 12

Name.

To honour Maxime Lamotte, the collector.

Material examined.

Holotype. Cameroon: ♂ (MNHN JB253), KumbaEtam, 25.XI.1975, leg. M. Lamotte.

Paratype. Cameroon: 1 ♂ (MNHN JB253), same place, together with holotype.

Description.

Length of holotype ca 26 mm, width of midbody pro- and metazonae 2.0 and 5.7 mm, respectively. The sole ♂ paratype is ca 27 mm long, 2.1 and 5.8 mm wide on pro- and metazonae, respectively. Metaterga and epiproct dirty brown dorsally, with lighter granulations and tubercles (Fig. 8); head and ventral sides of paraterga a little lighter, brownish; antennae, sides, venter and legs light, yellowish.

Head densely granulate-microtuberculate and setose on dorsal face, interantennal isthmus about half as broad as diameter of antennal socket. Antennae long and only slightly clavate, in situ reaching behind body segment 3 when stretched dorsally; antennomeres 5 and 6 each with a dorso-apical group of tiny bacilliform sensilla; in length, antennomere 6>2=5>1>7; apical segment with usual four sensory cones.

Body with 20 segments (♂). In width, segment head <collum <segment 2 <3 <4 <5 <6 = 15; body rapidly tapering from segment 18 towards telson. Collum transversely ellipsoid, not covering the head from above; sides narrowly rounded; dorsal surface densely irregularly granulate-tuberculate (Figs 8C, 9B). Dorsum strongly and mostly regularly convex (Figs 8, 9). Only prozonae smooth and shining; metazonae dull, densely tuberculate-granulate all over, devoid of a cerategument, but in places clothed with a crust of earth dirt; dorsal surface of metaterga and ventral sides of paraterga with 6-8 irregular transverse rows of small grains, tubercles or short spines, only marginal rows being regular and, on paraterga, composed of ca 10 tubercles in each fore and caudal row, and of 5-6 at lateral edge; stricture smooth. Metaterga 2-4 each with an increasingly prominent, caudally curved and nearly sharp, microgranulate, subcylindrical, central horn (Figs 8 A–D, 9). Metaterga 2-5 each with a small, but evident impression at base of paraterga, following paraterga (nearly) regularly convex, continuing the convex outline of mid-dorsal region. Paraterga very broad, set at about upper 1/3 of body, tips regularly rounded, mostly lying at about half of body height and slightly bent down; only paraterga 16-19 increasingly clearly drawn behind rear tergal margin, 19th sharp. Sides below paraterga densely granulate, grains in caudal row being longer, spiniform and sharp. Ozopores barely visible, open flush on surface near midlength slightly above lateral edge of paraterga; pore formula untraceable. A thin, dark, axial line sometimes traceable through a transparent tegument, best visible on collum and prozonae. Pleurosternal carinae wanting. Limbus entire, translucent. Epiproct short, small, spade-shaped, strongly flattened dorsoventrally, subtruncate, dorsally granulate-tuberculate (Fig. 8G). Hypoproct densely granulate-tuberculate, roundly subtrapeziform, with 1+1 caudal setae very distinctly separated and borne on minute knobs (Fig. 8E). Paraprocts likewise densely granulate-tuberculate (Fig. 8E).

Sterna broad, nearly twice as broad as coxa length, almost flat, densely setose (Fig. 8E). Gonapophyses on ♂ coxae 2 vestigial. Spiracles (Fig. 8A, C, F) tubiform, remarkably long and slender. Legs very long, about 2.0 times as long as midbody height (♂), very slender; in length, femur> tarsus> tibia> prefemur = postfemur = coxa; claw very small, very slightly curved; ventral surface of tarsi densely setose, but forming no brushes.

Gonopod aperture transversely ovoid, large, its lateral and posterior edges slightly elevated, fully concealing gonocoxae and bases of telopodites. Gonopods relatively complex (Figs 10, 11). Coxites medium-sized, subcylindrical, fused at base to a small membranous sternal remnant, poorly setose distodorsally, including a pair of very closely placed, distalmost and particularly long setae. Cannulae slender, without peculiarities. Telopodites in situ directed forward, held subparallel to each other, suberect, not crossing each other mesally. Prefemoral (= densely setose) part erect, taking up ca 2 /3 of total gonotelopodite length, without femorite, but with a relatively short, complex, tridentate, dorsal postfemoral process (pfp), set off from acropodite by a distinct cingulum; acropodite clearly twisted, divided parabasally into three large lobes, the middle of which forming a large solenomere lobe (slo) with only an indistinct, small solenomere proper on top, slo being neatly squeezed between a larger mesal uncus (u) and a smaller, subtriangular, lateral branch (lb), both u and lb forming a solenophore.

Remark.

At least at Kumba, the above new genus and species seems to occur sympatrically with Diaphorodesmus dorsicornis (Fig. 12). The label reading “KumbaEtam” is somewhat dubious. ‘Etam’ is a locality about 15 km NE of Kumba in Cameroon. The locality may therefore mean 'between Kumba and Etam’ or 'in the Kumba-Etam area’.