Plusioglyphiulus bessoni, Golovatch & Geoffroy & Mauriès & Den Spiegel, 2009

Plusioglyphiulus bessoni View in CoL n. sp.

( Figs 11-13)

TYPE MATERIAL. — Thailand. Nan, 18.776°N, 100.783°E, Cave Th am Pha Tup ( Tham Phra ), 10-11.VIII.1992, leg. J.-P. Besson, holotype ♂ ( MNHN GA057 ) GoogleMaps ; 2 ♂♂ paratypes, 1 ♀ paratype ( MNHN GA057); 1 ♀ paratype ( ZMUM); 1 ♀ paratype ( SEM).

ETYMOLOGY. — To honour Jean-Pierre Besson, who collected this material.

DIAGNOSIS. — Differs from congeners by certain details of gonopod structure (complicated anterior gonopods versus strongly simplified posterior ones), coupled with the mixostichic carinotaxy of the collum, the isostichic carinotaxy of other body segments, the convex paraprocts, the subtrapeziform epiproct and the absence of spots dorsad of the ocellaria.

DESCRIPTION

Length 25-43 mm, width 1.7-2.0 mm, collum and midbody segments being equally broadest.

Coloration usually uniformly grey-brown, sometimes with a paramedian pair of more or less wide, grey-yellowish stripes; collum and, in part, head and segment 2 entirely pale; tips of tergal crests/ tubercles usually dark brown; ocellaria dark brown to blackish, devoid of adjacent spots dorsally.

Body with 56-75p+4-1a+T. Length of holotype about 34 mm, width 2.0 mm, with 61p+4a+T.

Antennae more elongate ( Fig. 13A), antennomeres 6 and 7 each with a small group of bacilliform sensilla distodorsally. Ocellaria transverse and ribbonshaped, with 10-13 ocelli in 5-7 longitudinal rows. Gnathochilarium oligotrichous.

Postcollar constriction evident, but collum and segment 2 relatively modestly enlarged ( Fig. 11A). Carinotaxy formula of collum: ta/t+2p/t+// (t)+3p/t/t+4p/t/t+(ta)/(t)/(t)+5p/t/t+(ta)/t+pp/ t+ma/t ( Fig. 11A). Carinotaxy of metaterga 2 and 3, 8/8+m/m+8/8, all crests being longitudinal; formula of metatergum 4, 2+6/6+m/m+6/6+2; formula of metaterga 5-7, 3/3+I/i+3/3/3+m/m+3/3/3+I/ i+3/3; formula of subsequent metaterga, 3/3+I/ i+3/3/3+m/m/m+3/3/3+I/i+3/3; that of apodous segments, 3(4)+4(3)/4(3)+M(m/m)+4(3)/4(3)+3(4) ( Fig. 11A, C-F); all crests and tubercles rather high, poriferous cones (I) only slightly higher, and median ones (m) slightly lower, than others ( Fig. 11 B-E). Dorsal crests on several posteriormost segments considerably higher than others ( Fig. 11E). Midbody segments circular in cross-section ( Fig. 11B). Pleural regions of segments 2-4 conspicuously expanded, flap-shaped, especially so on segment 3 ( Fig. 11A). Pleural ridge behind gonopod aperture on male segment 7, tegument and an extremely finely and more or less regularly denticulate limbus ( Fig. 12C) as in other congeners. Epiproct relatively long, produced caudally and broadly subtrapeziform apically, with 1+1 paramedian tubercles at midway; paraprocts regularly convex, not flattened; hypoproct emarginate at caudal margin ( Figs 11E; 12A).

Legs short, on midbody segments about half as long as segment diameter ( Fig. 13E). Claw at base with a strong accessory spine almost half as long as claw itself ( Figs 12B, D; 13E). Tarsi, tarsal setae and male legs 1-3 ( Fig. 13 B-D) as in P. grandicollis .

Anterior gonopods ( Fig. 13F) much like in P. ampullifer n. sp., but processes cxp1 spiniform and non-contiguous; processes cxp2 slightly curved, broad, each with a flange on frontal face; telopodites (te) simple, lateral in position, movable, subcylindrical, setose laterally in distal half. Posterior gonopods ( Fig. 13G) relatively simple, without traces of telopodites; each coxite with a short sacciform structure (d) instead of arms, fovea-shaped apically and supplied with a sublateral spinicle.

REMARKS

Any obvious troglomorphic traits in this species seem to be absent.