Plusioglyphiulus panhai, 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 : 5-9

Plusioglyphiulus panhai sp. n. Figs 1−4.

Material examined: Holotype male ( MNHN GA 072 ), Thailand, Phachuap Khiri Khan Prov. , Sam Roi Yot Distr., Cave Tham Sai near sea shore, 20 m a.s.l., 14 December 2009, leg. S. Panha and members of the Animal Systematics Research Unit . Paratypes: 1 male, 1 female ( MNHN GA 072 ) , 1 male, 1 female ( ZMUM) , 1 male, 1 female ( MZCU) , 1 female ( ZMUC) , 1 male ( SEM) , same locality, together with holotype .

Name: Honours Professor Somsak Panha, one of the collectors and the leader of a highly active group of invertebrate taxonomists (the Animal Systematics Research Unit) at Chulalongkorn University, Bangkok, Thailand.

Diagnosis: Differs from congeners in the peculiar, reduced carinotaxy of the metaterga, e.g. the presence of only two, not the usual three, transverse rows of crests on the metaterga, coupled with the small central outgrowth on male leg-pair 1, by the simple, plate-like anterior gonopods vividly resembling those in most of Glyphiulus species , and the complex posterior gonopods whose coxites are densely setose paramedially and supplied apically with a large fovea and an evident uncus, while the telopodites are evident and digitiform.

Description: Length 31–45 mm, width 1.3–1.7 mm, collum and midbody segments being equally broadest. Coloration uniformly dark grey-brown; antennae lighter, usually yellow-brown; legs red-brown.

Body with 68–77p+2a+T. Length of holotype about 41 mm, width 1.7 mm, with 76p+2a+T.

Clypeus with three teeth anteromedially. Antennae short and clavate ( Figs 1A, 4A), antennomeres 6 and 7 each with a small group of bacilliform sensilla distodorsally ( Fig. 4A). Ocellaria large, vague due to complete depigmentation, ovoid in shape, with ocelli arranged at least in five longitudinal rows. Gnathochilarium ( Figs 2A, 4B) rather polytrichous, with a separate promentum (n=2).

Postcollum constriction rather evident, due to a moderately enlarged collum ( Fig. 1D). Carinotaxy formula of collum: 1p/t+2p/t/+3p/(t)/t/+4p/(t)/(t)/t+pp/(t)/(t)/t+/(t)+mp/m/m ( Figs 1A, D). Carinotaxy of metaterga 2–4, 4/ 4+m/m+4/4 ( Figs 1A, D); formula of following metaterga, 2/2+I/i+1/1+m/m+1/1+I/i+2/2 ( Figs 1A–C, E, F, 2E); all crests and tubercles, including poriferous cones, rather low. Dorsal crests on several posteriormost segments slightly higher than others ( Fig. 1C). Midbody segments ovoid in cross-section, nearly not compressed laterally ( Fig. 2E). Pleural regions of segments 2–4 conspicuously elongated, flap-shaped, especially so on segment 3 ( Fig. 1A). An evident, transverse pleural ridge behind gonopod aperture on male segment 7, with rounded flaps bent abruptly caudad. Tegument finely alveolate-areolate, dull throughout. Limbus very finely and rather regularly microdenticulate, thin. Epiproct broadly rounded apically, with 1+1 paramedian tubercles at midway; paraprocts evidently flattened, without an elevation at midline; hypoproct emarginate at caudal margin ( Figs 1C, F, 2D).

Legs rather short, nearly as long as body diameter ( Figs 2C, E), claws with an evident and long spine near base ( Figs 2F, 3A, 4F). Tarsi and tarsal setae very delicately fringed.

Male legs 1 with an unusually short central hook and relatively moderately reduced, 3-segmented appendages ( Figs 2B, 4C). Male legs 2 rather modestly enlarged, telopodite hirsute on frontal face; penes subtriangular, fused at base, with 2+2 long setae ( Figs 2B, 4D). Male legs 3 as usual, with particularly elongate and slender coxae, and shortened telopodites ( Figs 2B, 4E).

Anterior gonopods very simple, plate-shaped, much like in Glyphiulus , with a paramedian pair of anterior coxosternal processes (cxp) densely setose distally, digitiform, contiguous and only basally fused; ventrolateral corners of coxosternum with a conspicuous, rounded, nearly even lobe (lo); telopodites (te) elongate, digitiform, attached to coxal region on caudal face, probably capable of movement, each carrying a few setae subapically ( Figs 3D, 4G). Posterior gonopods smaller, complex, coxites well separated from sternum, densely setose paramedially, each surmounted by an evident fovea and a pointed uncus apically, and flanked laterally by a digitiform, apically finely fringed telopodite (te) ( Figs 3B, C, 4H).