Pseudotibiozus zophoribates, Enghoff & Larsson, 2018

Enghoff, Henrik & Larsson, Tobias Berglund, 2018, Pseudotibiozus Demange, 1970 - millipedes of the Eastern Arc Mountains, Tanzania (Diplopoda, Spirostreptida, Spirostreptidae), Zootaxa 4425 (3), pp. 541-554 : 545-552

Pseudotibiozus zophoribates sp. nov.

Figs 2 B , 3 E , 4 B, C , 5 B, D , 8

Diagnosis. Differs from the only known congener, P. cerasopus , by being larger (diameter of males 6.0– 6.6 mm, vs. 4.4–4.8 mm), by having the apical proplical lobe almost semi-circular with a parallel-sided, broadly or rounded mesapical process, and by having the apical lobe of metaplica almost egg-shaped.

Etymology. The name is a composite Greek noun in apposition, from zophos (darkness, dusk, also referring to the West) and oribates (mountaineer); it refers to the type locality, the West Usambara Mountains.

Material studied (total: 2 ♂♂)

Holotype: 1 ♂ TANZANIA, Tanga, W Usambara Mts, Mazumbai forest , 4°49’S, 38°30’E, 1400–1800 m asl, 10–20.xi.1995, C.E. Griswold, N. Scharff & D. Ubick leg. ( ZMUC)

Paratype: 1 ♂ same data ( ZMUC).

Description. Males.

SIZE. Body length 71–73 mm. Diameter 6.0– 6.6 mm. 43 body rings.

COLOUR (preserved specimens). Antennae and legs red, although less intensely so than in preserved specimens of P. cerasopus . Prozona and anterior part of metazona yellowish brown, posterior part of metazona dark brown, semi-transparent edge of metazona reddish.

MANDIBLES. Stipes with apicoventral lobe, no soft pad apically on the lobe. Gnathal lobe not studied with SEM, but apparently no group of small pointed pegs between pectinate lamellae and molar plate on dorsal surface, and no meso-dorsal lobe present between odontomere and sectile edge of psectromere.

GNATHOCHILARIUM ( Fig. 3 E ). Basal edge of median depression of mentum blunt, not overlying main part of mentum, not delimiting a proper cavity. Stipites without setae in basal half.

BODY RINGS ( Fig. 2 B ). Several rows of sigilla; rows sometimes irregular, especially below ozopore level.

LEGS. Length 0.9 × body diameter. First pair with only a few setae on coxosternum, not a large patch as in P. cerasopus . ( Fig. 5 B ).

GONOPODS ( Figs 5 D , 8 ). Proplica club-shaped: base relatively narrow, largest width subapically. Apical lateral lobe (apl) with regularly rounded margin continuing in broadly rounded mesapical lobe. Metaplica with mesal margin turning laterad at ca. 70° just before end of proplica, forming a blunt “corner”; apical lobe (aml) tongue- or egg-shaped, hardly projecting laterad. Antetorsal process (atp) of telopodite ( Fig. 5 D ) projecting obliquely mesodistad, tip just visible between pro- and metaplica ( Figs 8 C, D ).

Females. Unknown.

Distribution. Only known from the type locality, Mazumbai forest in the West Usambara Mountains ( Fig. 9 ).

Figures

FIGURE 2. Pseudotibiozus spp. A–B: midbody rings seen from the inside, showing sigilla (light spots) and dark ‘spikes’ projecting into light posterior part of metazona. A: P. cerasopus, specimen from East Usambara Mts, Amani, B: P. zophoribates sp. nov., paratype. C: P. cerasopus, specimen from East Usambara Mts, Amani, parts of three consecutive body rings, seen from the outside, showing dark ‘spikes’. Scales 1 mm. Abbreviations: ds = dark ‘spike’, oz = ozopore.

FIGURE 3. Pseudotibiozus spp., gnathochilarium. A–D: P. cerasopus, specimen from Udzungwa Mts. B: close-up of circled area (ss) in A. C: close-up of circled area in B. D: close-up of squared area in B. E: P. zophoribates sp. nov., paratype. Scales 1 mm (E), 0.2 mm (A), 0.05 mm (B), 0.005 mm (C, D). Abbreviations: ll = lamella lingualis, mda = median depressed area of mentum, sbs = basal field of stipital setae, ss = soft area with stout seta, st = stipes.

FIGURE 4. Pseudotibiozus spp. A: P. cerasopus (Attems, 1914), specimen from Udzungwa Mts, anterior end. B, C: P. zophoribates sp. nov., holotype. B: anterior end, C: telson. Scales 1 mm.

FIGURE 5. Pseudotibiozus spp., A, B: first pair of male legs. C, D: left gonopod telopodite. A, C: P. cerasopus (Attems, 1914) specimen from Udzungwa Mts. B, D: P. zophoribates sp. nov., paratype. Scales 0.2 mm (A), 0.5 mm (B—D). Abbreviations: atp = antetorsal process, cxs = field of coxosternal setae, pfl = prefemoral lobe.

FIGURE 8. Pseudotibiozus zophoribates sp. nov., holotype, gonopods (sternum missing). A: anterior view. B: posterior view. C: Tip of left pro- and metaplica. D: close-up of squared area in C, outline of antetorsal process traced in black. Scales 0.5 mm (A, B), 0.2 mm (C, D). Abbreviations: aml = apical metaplical lobe, apl = apical proplical lobe, atp = antetorsal process.

FIGURE 9. Pseudotibiozus spp., known distribution. Base map by permission of the Eastern Arc Mountains Conservation Endowment Fund.