Plusioglyphiulus antiquior, Golovatch & Geoffroy & Mauriès & Vandenspiegel, 2011

Golovatch, Sergei I., Geoffroy, Jean-Jacques, Mauriès, Jean-Paul & Vandenspiegel, Didier, 2011, The millipede genus Plusioglyphiulus Silvestri, 1923 in Thailand (Diplopoda, Spirostreptida, Cambalopsidae) 2940, Zootaxa 2940 (1), pp. 1-63 : 9-12

Plusioglyphiulus antiquior sp. n. Figs 5−7 .

Material examined: Holotype male ( MNHN GA 075 ), Thailand, Kanchanaburi Prov., Sai Yok Distr., Cave Tham Sai Yok Noi , hand collection, 18 June 1986, leg. P. Leclerc (THA-KAN-042).

Paratypes: 1 female ( MNHN GA 075 ), same locality, together with holotype ; 1 male, 1 female, 1 female fragment ( MNHN GA 075 ), same locality, 15 June 1986, leg. P. Leclerc (THA-KAN-037) .

Name: To emphasize an even more basal position of this species in Plusioglyphiulus compared to the previous one.

Diagnosis: Differs from congeners in the especially strongly reduced carinotaxy of the collum and metaterga resembling that of typical Glyphiulus , e.g. the absence of a transverse sulcus to set the caudal row of crests, coupled, like in the apparently most similar P. panhai sp. n., with two, not the usual three, transverse rows of crests on the metaterga, as well as the relatively small central uncus on male leg-pair 1, the simple, plate-like anterior gonopods, and the complex posterior gonopods retaining evident telopodites.

Description: Length 18–22 mm, width 1.0 mm, midbody segments being broadest. Coloration uniformly pallid to light yellow.

Body with 41–50p+3–1a+T. Length of holotype about 21 mm, width 1.0 mm, with 49p+1a+T.

All characters as in P. panhai sp. n. ( Figs 5B, C, E, F , 6B–D, F, G , 7A, E ), except as follows. Ocellaria invisible due to complete depigmentation. Gnathochilarium ( Fig. 7B ) not so strongly polytrichous, with a separate promentum (n=2).

Postcollum constriction rather evident, due to a moderately enlarged collum ( Figs 5D , 6A ). Carinotaxy formula of collum: 1+2+3p/(t)+4p/+pp/(t)+//ma ( Figs 5A, D ). Midbody segments ovoid in cross-section, almost not compressed laterally ( Fig. 6E ). Rounded pleural flaps behind gonopod aperture on male segment 7 smaller.

Male legs 1 with an unusually short central hook and relatively strongly reduced, 2-segmented telopodites ( Fig. 7C ). Male legs 2 modestly enlarged, telopodite hirsute on frontal face; penes subconical, fused at base, with 2+2 long setae ( Fig. 7D ).

Anterior gonopods very simple, plate-shaped, much like in typical Glyphiulus species , virtually identical to those of P. panhai sp. n., including high and densely setose anterior coxosternal processes (cxp) and digitiform telopodites (te), but ventrolateral corners of coxosternum with far less conspicuous and more papillar lobes ( Fig. 7F ). Posterior gonopods also virtually identical to those of P. panhai sp. n., each with an evident fovea apically, but devoid of a flagellum; telopodite (te) micropapillar on mesal face ( Fig. 7G ).

Figures

FIGURE 5. Plusioglyphiulus antiquior sp. n., female paratype. A: anterior part of body, lateral view. B: midbody segments, lateral view. C: posterior part of body, lateral view. D: anterior part of body, dorsal view. E: midbody segments, dorsal view. F: posterior part of body, dorsal view. Scale bars: A–F, 0.2 mm.

FIGURE 6. Plusioglyphiulus antiquior sp. n., female paratype. A: anterior part of body, ventral view. B: midbody segments, ventral view. C: posterior part of body, ventral view. D: same, caudal view. E: cross-section of a midbody segment, caudal view. F: enlarged ozopore region, lateral view. G: enlarged claw, lateral view. Scale bars: A–E, 0.2 mm; F, 0.05 mm; G, 0.01 mm.

FIGURE 7. Plusioglyphiulus antiquior sp. n., male holotype. A: antenna, lateral view. B: gnathochilarium, ventral view. C: leg 1, subcaudal view. D: leg 2, caudal view. E: midbody leg. F: anterior gonopods, caudal view. H: posterior gonopods, front view. te: telopodite; cxp: coxosternal process. Scale bar: 0.2 mm.