Pseudotibiozus Demange, 1970

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 : 542-543

Pseudotibiozus Demange, 1970

Type species. Mardonius cerasopus Attems, 1914 , by original designation.

Other included species. Pseudotibiozus zophoribates sp. nov.

Diagnosis. A genus of Spirostreptidae characterized by the following combination of gonopodal characters: Apical lateral process of metaplica short, rounded. Antetorsal process of telopodite very short, branching off from main telopodite stem before the telopodite curves laterad and exits the coxa. Telopodite becoming thicker shortly after exiting coxa and flattening to an almost ribbonlike structure, telopodite bending mesad at mid-length and dividing into a spinelike branch and a thinner solenomere, solenomere twisting up and around the spinelike branch in an overall mesad direction. Tip of solenomere wrinkled, spongelike.

General description of Pseudotibiozus .

Males. SIZE. Body length 52–73 mm; diameter 4.4–6.6 mm. 41–43 podous rings, no apodous rings in front of telson.

COLOUR. Live colour contrastful (black body, red legs) in P. cerasopus ( Fig. 1 ), not known in P. zophoribates sp. nov. Metazona of preserved specimens with a light band posteriorly. Dark colouration anteriorly of the band extended as tiny dark 'spike' (ds) into light posterior band at level of ozopore (oz) (even on ozopore-less rings), one or two additional 'spikes' may also be present; 'spikes' difficult to see from the outside ( Fig. 2 C ), especially on fresh specimens, but conspicuous when the body ring is seen from the inside ( Figs 2 A, B ).

HEAD ( Figs 3 , 4 A, B ). Four supralabral setae. Eyes extending mesad just beyond antennal sockets. Ca. 11 vertical rows of ommatidia, ca. 48 ommatidia. Mandibular stipes with apicoventral lobelike extension. (Details of mandibular gnathal lobe are described under P. cerasopus ). Gnathochilarium ( Fig. 3 ): Mentum with median depressed area (mda); lamellae linguales (ll) each with two strong apical setae, one similar-sized seta behind the two and two to three basal setae of varying size; stipites (st) with several setae along latero-apical edge, with or without a field of setae (sbs) basally, with a single stout setae placed in a soft area (ss) near tip.

COLLUM ( Figs 4 A, B ). Lateral lobes rectangular, with 4–5 striae.

BODY RINGS ( Figs 2 , 4 ). Prozonal ring furrows very weak. Metazona vaulted and with longitudinal striae from below ozopores and downward, striae in lover part of striate area more ridgelike and ending in denticles at metazontal hind edge. Ozopore situated ca. 1/3 metazona length behind suture, a weak horizontal suture from ozopore to metazonal hind margin. Sigilla ( Fig. 2 ) obvious, in one or several rows.

TELSON ( Fig. 4 C ). Preanal ring with slightly curved dorsal margin, posteriorly with a more or less straight edge, i.e., no proper epiproct; hypoproct a narrow band; anal valves with a submarginal depression, margins forming blunt ‘lips’.

LEGS. As long as body diameter or slightly shorter. Tibia with small apical ventral pad extending under basis of tarsus; no pads on other podomeres. First pair ( Fig. 5 ) with short, triangular basal prefemoral lobes (pfl), with or without a field of coxosternal setae (cxs).

GONOPODS ( Figs 5 C, D , 7 , 8 ). Sternum (st) blunt triangular to subsemicircular, not reaching as far distal as paracoxites (px). Proplica (pp) straight, ending in a simple apical lobe (apl) with a small patch of short setae at its base. Metaplica (mp) longer than proplica, apically with a triangular-rounded or ovoid lobe (aml). Telopodite (tlp) ( Figs 5 C, D ) with a very small antetorsal process (atp) originating before the telopodite bends laterad and exits from the coxa, atp hence either completely hidden between pro- and metaplica or barely projecting ( Figs 8 C, D ). Telopodite ribbonlike from emergence from coxa, ca. at midlength bending mesad and dividing into a mesad spinelike branch (sb) and a thinner solenomere (slm); solenomere twisting around sb in an overall mesad direction. Tip of telopodite strongly wrinkled, spongelike ( Fig. 7 E ).

Females (known only for P. cerasopus ). Thicker than males, with relatively shorter legs, lacking modifications of mandibular stipes and legs. 40–44 podous body rings, no apodous rings in front of telson.

Figures

FIGURE 1. Pseudotibiozus cerasopus (Attems, 1914), specimen from the Udzungwa Mts. Photo by N. Scharff.

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 7. Pseudotibiozus cerasopus (Attems, 1914), specimen from Udzungwa Mts, gonopods. A: anterior view. B: posterior view. C: left telopodite. D: proplical setae (circled area in A). E: tip of solenomere. Scales 0.2 mm (A, B), 0.1 mm (C), 0.02 mm (D), 0.01 mm (E). Abbreviations: aml = apical metaplical lobe, apl = apical proplical lobe, map = mesapical process of proplica, mp = metaplica, pp= proplica, px = paracoxite, sb = spinelike branch, slm = solenomere, st = sternum, tlp = telopodite.

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.