Tropostreptus droides, Enghoff, Henrik, 2017

Enghoff, Henrik, 2017, A new East African genus of spirostreptid millipedes (Diplopoda, Spirostreptida, Spirostreptidae), with notes on their fungal ectoparasite Rickia gigas, Zootaxa 4273 (4), pp. 501-530 : 520-521

Tropostreptus droides sp. nov.

Figs 2 , 4 A, 7E, 8E

Diagnosis. A small species of Tropostreptus ( Fig. 2 ). Differs from other species, except T. kipunji , by the combination of size and the latero-basad direction of the metaplical process corresponding to the birdhead-shaped process of most other species. Differs from T. kipunji by larger size, a blunter tip to the latero-basad metaplical process and a longer, more curved antetorsal process (atp) of the telopodite.

Etymology. The name is an adjective and refers to the (rather remote) resemblance between the gonopod coxae of the new species and a pair of Star Wars battle droids.

Material studied (total: 6 ♂♂, 5 ♀♀, 3 juv.)

Holotype: ♂ TANZANIA, Udzungwa Mts., Iringa Region, Udzungwa Scarp Forest Reserve, above Chita village , 1600–1650 m asl, montane rain forest, 8–12.xi.1984, N. Scharff leg. ( ZMUC).

Paratypes: 1 ♂ same data as holotype, but 1500–1550 m asl, 2–13.xi.1984 ( ZMUC) .— 2 ♀♀, 2 juv. same data, but 1600–1650 m asl, pitfall traps in montane rainforest, 8–13.xi.1984 ( ZMUC) .— 1 ♂, 2 ♀♀, 1 juv. same data, but 1300–1400 m asl, montane rain forest, 26.x.–14.xi.1984. — 1 ♂, 1♀ TANZANIA, Iringa Region, Mufindi District, Kigige [probably wrong for Kigogo ] Forest Reserve , 8.35°S, 35.20°E, ca. 6000 ft asl, K.M. Howell & B. Zuidberg leg., C. Congdon ded. ( VMNH) .— 1 ♂ TANZANIA, Iringa Region, Mufindi District, Kigogo Forest Reserve, near Mufindi Brook Bond Tanzania tea est., in forest, under log, 1830 m asl, 19.v.1984, K.M. Howell & E. Boswell leg. ( VMNH) .

Type locality: TANZANIA, Udzungwa Mts., Iringa Region, Udzungwa Scarp Forest Reserve, above Chita village , 1600–1650 m asl, montane rain forest

Description. SIZE ( Fig. 2 ). Length 6½ – 7 cm; vertical body diameter 5.4–6.3 mm (males), up to 6.8 mm (females); 44–49 podous rings.

COLOUR. After 32 years in alcohol head, antennae, collum and telson yellow; legs light brown; body rings yellow, posterior ca. 1/8 amber.

GONOPODS ( Figs 7 E, 8E). Sternum triangular, not reaching as far as paracoxites, bell-shaped. Proplica ending in triangular to semicircular lobe (mpl) separated by sinus from large apico-lateral, sub-semicircular lobe (lpl). Apical lobe (mpl) reaching further distad than apico-lateral one (lpl). Metaplica apically rounded, with a blunt latero-basad process (corresponding to the birdhead-shaped process of most other congeners). Telopodite shortly after emergence from coxa with very long, slender, pointed, antetorsal process (atp); initial overall direction of process basad, then laterad, then apicad. Telopodite distal to antetorsal process without outgrowths.

Distribution. Known from two forest reserves in the SW part of the Udzungwa Mts: Udzungwa Scarp and Kigogo, altitude 1300–1830 m asl.

Coexisting congeners. None.

Infection with Rickia gigas . A male from Udzungwa Scarp Forest Reserve was infected with long-celled Rickia gigas on the inside of leg-pairs 3–7.

Figures

FIGURE 2. Size of Tropostreptus males, expressed as number of podous rings and midbody vertical diameter. Females reach higher diameters than males. See Figs. 11 and 13 for details on T. hamatus and T. sigmatospinus sp. nov.

FIGURE 4. Tropostreptus spp., mouthparts. A: T. droides sp. nov., left mandibular gnathal lobe, dorsal / anterior view, B: T. kipunji sp. nov., right mandibular gnathal lobe, mesal view. C: T. hamatus, male, gnathochilarium and right mandible, oblique ventral view. — Scales 0.1 mm. me = mentum, mf = molar furrow, msl = mandibular stipital lobe, od = odontomere, pl = pectinate lamellae, pm = prementum, ps = psectromere, se = sectile edge.

FIGURE 7. Tropostretus spp., gonopods, anterior view. A: T. hamatus, East Usambara Mts, B: T. hamatus, Udzungwa Mts., left telopodite missing, C: T. sigmatospinus sp. nov., D: T. microcephalus sp. nov., E: T. droides sp. nov., F: T. kipunji sp. nov. Scales 0.5 mm. atp = antetorsal process, bh = birdhead-shaped metaplical process, lpl = apicolateral proplical lobe, map = mesapical metaplical process, mp = metaplica, mpl = mesapical proplical lobe, pp = proplica, px = paracoxite, st = sternum, tlp = telopodite.