Metopidiothrix taiwanensis, Mikhaljova, Elena V., Golovatch, Sergei I. & Chang, Hsueh-Wen, 2011

Mikhaljova, Elena V., Golovatch, Sergei I. & Chang, Hsueh-Wen, 2011, The millipede family Metopidiotrichidae new to the fauna of Taiwan: the description of a new species; a review of and a key to the Chordeumatida occurring in Taiwan (Diplopoda), Zootaxa 3104, pp. 59-63 : 60

Metopidiothrix taiwanensis sp. nov.

Figs 1–9

Material examined. Holotype: male ( NMNS, 6708–001), Taiwan, Pingtung County, Manzhou Township, Lan-Jen Stream, 50 m a.s.l., 23.III.2002, leg. C.N. Wu et al. Paratype: 1 female (NSYSUB), same locality, 23.III.2002, leg. C.C. Chen.

Diagnosis. Differs from other congeners mainly by the shape of the posterior gonopod coxite which shows two simple branches of different length, by the somewhat flattened, mesally curved distal part of the anterior gonopod, by the strongly enlarged male legs 3, as well as by the denticulate margins of the spermatophoral cavity of the female syncyphium.

Description. Male. Length ca 4.3 mm, width about 0.5 mm. Coloration grey-brown with a green tinge (the latter likely due to staining the gonopod block in intense blue-green). Front body portion infuscate. Head generally dark grey-brown, clypeolabral region lighter, labrum whitish. Ocellaria dark grey-brown. Antennae grey-brown, their distal parts lighter.

Body with 32 segments. Head strongly modified, characteristic of male Metopidiothrix , with an enlarged clypeolabral region set off from a strongly narrowed labrum by a distinct sulcus with a deep flexure backwards in clypeolabral region, creasing head across just below antennal sockets, forming a sharp angular projection on each side below and in front of antennae, and making it swollen and strongly sclerotized. Below crease, labrum strongly narrowed and flat. Clypeal knob acute, labral knobs tiny, with setae at base. Genae strongly convex, subquadrate. Ocellaria subtriangular, each composed of at least 12 ocelli. Antennae slightly clavate, long, extending behind until end of segment 5 when stretched laterally; antennomeres 1 and 2 each with a distodorsal knob supporting one (antennomere 1) or two (antennomere 2) thick dendroid setae ( Fig. 1 ). Collum semi-circular. Body with very small, rounded paraterga growing increasingly reduced towards telson. Each metatergum with 3+3 long macrochaetae, all subequal in length and pointed.

Walking legs each with a claw supplied with a strong filament ventrally at base. Tarsal papillae absent. Leg pair 3 very strongly enlarged, 4–5 times thicker, but not much longer than normal legs; tarsus rather short and pyriform, bearing special, strong setae; prefemur strongly swollen and setose ventrally ( Fig. 2 ). Leg pair 10 with telopodites reduced to one small button-shaped segment and evident gland sacks ( Fig. 3 ). Leg pair 11 with coxae setose both subapically and, especially, ventro-parabasally, supplied with strong mesal hooks rounded at tip ( Fig. 4 ).

Anterior gonopods ( Figs 5–7 ) with a large shelf extending well mesad, carrying short setae on tips; a rodshaped process wanting; both median coxosternal angles well-developed. Posterior gonopods ( Figs 6–8 ) with prominent branched coxites; anterior branch shorter and stout, carrying a gland channel; posterior branch longer and slender, pointed apically.

Female. Length about 5.5 mm, width about 0.5 mm. Coloration generally light brown with brown prozona. Venter beige. Front part of body infuscate, castaneous brown. Clypeolabral region light brown, other parts except labrum brown, labrum and telson whitish. Antennae brownish, distally lighter. Ocellaria black. Body with 32 segments. Ocellaria composed of at least 13 ocelli.

Fused cyphopods, or vulvae, termed a syncyphium ( Shear 2002), with two dentiform outgrowths, one on each side of a large cavity (= fossa) designed for accommodation of spermatophores; central plate also bearing two dentiform processes ( Fig. 9 ).

Name. The specific epithet refers to Taiwan, the terra typica.

Figures

FIGURE 9. Metopidiothrix taiwanensis sp. nov., female paratype. Syncyphium, ventral view. Scale in mm.

FIGURES 1 – 8. Metopidiothrix taiwanensis sp. nov., male holotype. 1, distinctive setae of antennomere 2 (not drawn to scale); 2, leg 3, caudal view; 3, leg pair 10, caudal view; 4, coxae 11, caudal view; 5, anterior gonopods, caudal view; 6, gonopods, caudal view; 7, gonopods, front view; 8, posterior gonopods, caudal view. Scales in mm.