Plusioglyphiulus tham, 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 : 32-35

Plusioglyphiulus tham sp. n. Figs 28−31 .

Material examined: Holotype male ( MNHN GA 067 ), Thailand, Chaiyaphum Prov., Phaedee Chumpon Distr., Cave Tham Keo , 15°58’30”N, 101°24’40”E, 350 m a.s.l., guano, 1 November 2010, leg. N. Likhitrakarn. Paratypes: 19 males, 14 females ( MNHN GA 067 ) , 2 males, 2 females ( ZMUM) , 2 males, 2 females ( ZMUC) , 2 males, 2 females ( MZCU) , 2 males, 2 females ( NMNHS) , 1 male ( SEM) , same locality, together with holotype .

Name: To emphasize “tham”, in Thai meaning “cave”, as the type locality, a noun in apposition.

Diagnosis: Differs from congeners in the oligotrichous gnathochilarium, coupled with the presence of 2+2 dorsal tubercles on the epiproct, the absence of a transverse sulcus setting off the caudal parts of the carinae on the collum, the particular carinotaxy patterns, and the special shapes and armature of both gonopod pairs (see also Key below).

Description: Length 20–28 mm, width 1.1–1.5 mm, collum and segments in posterior third of body being equally broadest. Coloration uniformly dark grey-brown to light (yellow-) brown; antennae and collum sometimes lighter, then brown; metatergal crests and, especially, poriferous tubercles usually infuscate.

Body with 41–59p+4–1a+T. Length of holotype about 21 mm, width 1.3 mm, with 50p+2a+T.

All characters as in P. panhai sp. n. ( Figs 28E, F , 29C, D, F , 30A , 31A ), except as follows. Ocellaria large, blackish, ovoid in shape, with about 16–20 ocelli arranged in 4–6 longitudinal rows. Gnathochilarium ( Figs 29B , 31B ) rather oligotrichous, with a separate promentum (n=2).

Postcollum constriction very evident, due to especially enlarged collum and segment 2 ( Figs 28A, D , 29A ). Carinotaxy formula of collum: //(t)+/(t)/+1p/t+2+3a+4+5a+P+/ma ( Figs 28A, D ). Carinotaxy of metaterga 2–4, 7/ 7+m/m+7/7; usual formula of all following metaterga, 3/3+I/i+3/3/3+m/m/m ( Figs 28A–C , 29E ); all crests and tubercles, including poriferous cones, rather low. Epiproct dorsally with 2+2 knobs arranged in a transverse row ( Fig. 28F ). Midbody segments ovoid in cross-section, slightly compressed laterally ( Fig. 29E ).

Male legs 1 with a usual strong central hook curved forward, appendages larger, sac-shaped, with a few setae mesally near base, 1-segmented. Male legs 2 strongly enlarged.

Anterior gonopods complex, with a paramedian pair of anterior coxosternal processes (cxp1), relatively high, rather slender, largely widely separated, twisted and serrate/setose; caudal pair of coxosternal processes (cxp2) similarly high and almost straight; telopodites (te) club-shaped, enlarged, densely setose on mesal face, slightly higher than cxp2, attached to coxal region caudally, probably not capable of movement ( Figs 30B–D , 31C ). Posterior gonopods considerably shorter, simple, coxites well separated from sternum, barely fused only basally, sacshaped to coniform, membranous, each surmounted on frontal face by an evident fovea devoid of clear-cut flagella nearby; telopodites virtually missing ( Figs 31D, E ).

Figures

FIGURE 28. Plusioglyphiulus tham sp. n., male 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 and B, 0.5 mm; C–F, 0.2 mm.

FIGURE 29. Plusioglyphiulus tham sp. n., male paratype. A: anterior part of body, ventral view. B: gnathochilarium, ventral view. C: midbody segments, ventral view. D: posterior part of body, ventrocaudal view. E: cross-section of a midbody segment, caudal view; F: enlarged ozopore region. Scale bars: A, 0.5 mm; B–E, 0.2 mm; F, 0.1 mm.

FIGURE 30. Plusioglyphiulus tham sp. n., male paratype. A: enlarged claw, ventrolateral view. B: anterior gonopods, frontoventral view. C: same, caudal view. D: same, caudoventral view. Scale bars: A, 0.02 mm; B−D, 0.1 mm.

FIGURE 31. Plusioglyphiulus tham sp. n., male paratype. A: antenna, lateral view. B: gnathochilarium, ventral view. C: right anterior gonopod, caudal view. D: left posterior gonopod, caudal view. E: same, front view. te: telopodite; cxp1: anterior coxosternal process; cxp2: posterior coxosternal process. Scale bar: A and B, 0.4 mm; C and D, 0.2 mm.