Orthomorpha communis, Likhitrakarn, Natdanai, Golovatch, Sergei I. & Panha, Somsak, 2011

Likhitrakarn, Natdanai, Golovatch, Sergei I. & Panha, Somsak, 2011, Revision of the Southeast Asian millipede genus Orthomorpha Bollman, 1893, with the proposal of a new genus (Diplopoda, Polydesmida, Paradoxosomatidae), ZooKeys 131, pp. 1-161 : 29-31

Orthomorpha communis sp. n. Figs 2527

Holotype.

♂ (CUMZ), Thailand, Surin Prov., Mueang Surin Distr., Khao Phanom Sawai National Park, ca 200 m, 14°15'45"N, 103°22'07"E, 26.04.2009, leg. N. Likhitrakarn.

Paratypes.

1 ♂, 1 ♀ (ZMUC), 1 ♂, 1 ♀ (ZMUM), 3 ♀ (CUMZ), same data, together with holotype. 2 ♂ (CUMZ), Prachinburi Prov., Prachantakham Distr., Takror Waterfall, ca 30 m, 14°10'53"N, 101°35'32"E, 18.09.2009, leg. N. Likhitrakarn. 1 ♂ (ZMUC), 1 ♂ (ZMUM), 1 ♀(CUMZ), same Prov., Na Di Distr., Nong Tabaek Waterfall, ca 40 m, 14°07'53"N, 101°40'41"E, 18.09.2009, leg. N. Likhitrakarn. 1 ♂ (CUMZ), Ubon Ratchathani Prov., Khong Chiam Distr., Patam National Park, ca 210 m, 15°23'55"N, 105°30'27"E, 25.04.2009, leg. P. Pimvichai. 2 ♀ (ZMUC), 2 ♀ (ZMUM), 2 ♂, 6 ♀ (CUMZ), same Distr., Tadtong Waterfall, ca 170 m, 15°15'14"N, 105°28'41"E, 14.05.2011, leg. N. Likhitrakarn.

Name.

To emphasize this species being quite common in the eastern part of Thailand close to the border with Cambodia.

Diagnosis.

Differs in unequal terminal lobes of the solenophore, both of which show a minute tooth near their bases, coupled with pointed, subtriangular paraterga on the collum etc. (see also Key below).

Description.

Length 31-38 (♂) or 32-38 mm (♀), width of midbody pro- and metazona 2.6-4.0 and 4.2-4.7 mm (♂), 3.2-3.8 and 4.8-5.3 mm (♀), respectively.

Coloration of live animals (Fig. 25A) blackish-brown, paraterga and epiproct contrasting creamy yellow, antennae dark brown, legs brownish; coloration of alcohol material after preservation (Fig. 25B-J) uniformly blackish-brown with contrasting light yellowish-brown paraterga and epiproct, tip of antennae pallid, venter and basal 3-4 podomeres brown to grey-brown.

Clypeolabral region densely setose, vertex sparsely setose, epicranial suture distinct. Antennae moderately long, clavate (antennomere 6 broadest), extending behind body segment 2 (♂) (Fig. 25A & C) or collum (♀) dorsally. Head in width <collum <segments 3 and 4 <2 <5-16 (♂, ♀); thereafter body gently and gradually tapering. Collum with three transverse rows of setae: 4+4 anterior, 2+2 intermediate, and 3+3 posterior; paraterga subtriangular, lying in a slightly rugulose posterior 1/3 of collum, slightly declined ventrally and continuing collum convexity (Fig. 25B); caudal corner of paraterga pointed. Tegument smooth and shining, prozona very finely shagreened, metazona leathery, faintly rugulose, below paraterga microgranulate. Metaterga 2-18 with an anterior transverse row of 2+2, mostly abraded setae; caudal row barely traceable only as 3+3 or 4+4 insertion points better visible laterally as minute knobs or oblong wrinkles. Metatergum 19 with 3+3 anterior and 4+4 posterior setae, the latter also borne on minute knobs. Tergal setae simple, rather long, about 1/3 metatergal length. Axial line barely traceable only on some metaterga, never complete. Paraterga very strongly developed (Fig. 25A-H), especially well so in ♂, all lying below dorsum (at about 1/3 body height), subhorizontal, in lateral view modestly enlarged on pore-bearing segments, thinner on poreless ones; shoulders always present, regularly rounded and narrowly bordered, fused to callus; caudal tip of all paraterga pointed, beak-like, lying within rear tergal margin or almost so on segments 2-7, thereafter extending increasingly beyond it, best developed and slightly curved mesad on segments 17-19 (Fig. 25F). Calluses delimited by a sulcus both dorsally, and, albeit more poorly so, ventrally, in dorsal view narrower on poreless segments than on pore-bearing ones, with three small, but evident lateral incisions on callus 2, with two similar incisions on following poreless segments, with one, often setigerous incision in front of pore on pore-bearing segments. Posterior edge of paraterga evidently concave, especially strongly so on segments 16-19. Ozopores evident, lateral, lying in an ovoid groove at about 1/4 in front of caudal corner. Transverse sulcus highly incomplete and visible only mid-dorsally on segment 2, complete on metaterga 5-18, narrow, rather deep, reaching bases of paraterga, finely beaded at bottom, better developed in ♀. Stricture between pro- and metazona narrow and rather shallow, evidently beaded at bottom down to base of paraterga (Fig. 25B, D, E & H). Pleurosternal carinae complete crests with a sharp caudal tooth on segments 2 and 3, onward as increasingly poorly developed, flat ridges with small caudal teeth until segment 12, thereafter only as an increasingly small, sharp, caudal tooth on segment 16. Epiproct (Fig. 25F-H) conical, flattened dorsoventrally, with two evident apical papillae directed ventrocaudally, subtruncate at tip; pre-apical papillae large, lying close to tip. Hypoproct (Fig. 25G) subtriangular, caudal margin rounded, setiferous knobs at caudal edge very large and well-separated.

Sterna sparsely setose, without modifications; cross-impressions shallow; with a paramedian pair of very small, flat, strongly separated, setose knobs between ♂ coxae 4 (Fig. 25I & J). A paramedian pair of small tubercles in front of gonopod aperture. Legs moderately long and slender, slightly incrassate in ♂, midbody ones ca 1.1-1.3 (♂) or 0.8-0.9 times (♀) as long as body height, prefemora without modifications, ♂ tarsal brushes present only on legs 1-7.

Gonopods (Figs 26 & 27) simple. Coxa long and slender, with numerous strong setae distodorsally and distolaterally. Prefemur densely setose, nearly 3 times shorter than femorite + “postfemoral” part. Femorite slender, slightly curved and not enlarged distad, with a “postfemoral” part demarcated by an oblique lateral sulcus. Solenophore with a bidentate tip, terminal denticle a little larger than subterminal one, both being supplied with an extremely small indentation near base; solenomere long and flagelliform.

Remarks.

This new species appears to be quite widespread in the eastern part of Thailand close to the border with Cambodia (Map 2).