Orthomorpha spiniformis, 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 : 97-101

Orthomorpha spiniformis sp. n. Figs 109111

Holotype.

♂ (CUMZ), Malaysia, Pahang State, Panang National Park, ca 80 m, 3°52'22"N, 102°19'20"E, 23.05.2011, leg. S. Panha.

Paratypes.

1 ♂, 1 ♀ (CUMZ), same State, Lake Kenyir, ca 170 m, 4°50'44"N, 102° 43'15"E, 25.05.2011, leg. S. Panha.

Name.

To emphasize the spiniform paraterga.

Diagnosis.

Differs in strongly spiniform paraterga, coupled with virtually smooth metaterga etc. (see also Key below).

Description.

Length 25-28 mm (♂), 29 mm (♀), width of midbody pro- and metazona 2.0-2.2 and 3.1-3.5 mm (♂), 2.4 and 3.5 mm (♀), respectively.

Coloration of live animals blackish-brown, calluses of paraterga (especially caudal parts) and distal half of epiproct contrasting red-brown; legs and venter yellow to light brown (Fig. 109A); coloration of alcohol material after long-term preservation faded to dark castaneous brown, paraterga contrasting pallid to very light brownish, antennomeres 1-4 very light brown, distal antennomeres brown (Fig. 109B-H).

Clypeolabral region densely setose, vertex bare, epicranial suture distinct. Antennae short, poorly clavate (Fig. 109A), extending behind (♂) or not reaching end of segment 2 (♀) dorsally. Head in width << collum <segment 3 = 4 <2 <5-17 (♂, ♀); thereafter body gently and gradually tapering. Collum semi-lunar, with an untraceable pattern of setation, surface rugulose, middle slightly flattened; paraterga narrowly subtriangular, subspiniform, devoid of lateral incisions; caudal corner nearly pointed, not extending behind tergal margin (Fig. 109B & C). Tegument rather poorly shining, prozona very finely shagreened, metaterga rugose to rugulose (especially well so near bases of paraterga), finely granulate, below paraterga microgranulate. Postcollum metaterga with two transverse rows of short, mostly abraded setae traceable only as insertion points or short wrinkles: 2+2 in front (pre-sulcus) row without wrinkles and 2+2 (or 3+3?) in caudal (postsulcus) row on wrinkles (Fig. 109B-F). Axial line rather clear, especially so on postsulcus halves of metaterga. Paraterga very strongly developed (Fig. 109A-H), especially well so in ♂, always spiniform and pointed, mostly subhorizontal to faintly upturned, level to or slightly above dorsum, only on segments 1-4 and 19 evidently below dorsum, set at about 1/4 midbody height; shoulders strongly and regularly rounded, well-developed, caudal corners of postcollum paraterga always extending beyond tergal margin. Calluses delimited by a sulcus both dorsally and ventrally, especially deeply so dorsally, rather na rrow, with 3-4 small lateral incisions on callus 2 and one similarly unclear indentation on each following segment, these indentations lying at about front 1/3 on poreless segments and at about 1/2 on pore-bearing ones (Fig. 109B, D & F). Posterior edge of paraterga always very evidently concave, more strongly so on segments 16-19 (Fig. 109F). Ozopores evident, lateral, lying in a deep ovoid groove at about 1/3-1/4 paratergal length in front of caudal corner. Transverse sulcus present on metaterga 5-17, complete and reaching bases of paraterga, incomplete and faint on metatergum 18 (♂, ♀), beaded at bottom, rather deep (Fig. 109B, D & F). Stricture between pro- and metazona deep, narrow, evidently ribbed at bottom down to base of paraterga. Pleurosternal carinae poorly developed, especially so in ♀, as small, complete and roughly granulate crests with a distinct tooth both frontally and caudally only on segments 2-4, traceable as a small caudal denticle on segments 5-7 (♂) or 5 and 6 (♀) (Fig. 109C, E & H). Epiproct (Fig. 109F-H) conical, rather short, flattened dorsoventrally, with two very strong pre-apical papillae strongly removed from a deeply emarginate tip. Hypoproct (Fig. 109G) roundly subtrapeziform, setiferous knobs at caudal edge very small and well-separated.

Sterna shining, sparsely setose; a paramedian pair of evident, fully separated, anteroventrally directed, setose cones between ♂ coxae 4 (Fig. 109I & J), these being similar in size to those in front of gonopod aperture. Legs long and slender, almost not incrassate in ♂, midbody ones ca 1.6-1.7 (♂) or 1.1-1.2 times (♀) as long as body height, prefemora without modifications, ♂ tarsal brushes present only on ♂ legs 1-2, thereafter gradually thinning out.

Gonopods (Figs 110 & 111) simple. Coxa long and slender, with several strong setae distodorsally. Prefemoral portion densely setose, about 3 times shorter than femorite + “postfemoral” part. Femorite slender, slightly curved, nearly not enlarged distad, with a “postfemoral” part demarcated by an oblique lateral sulcus. Solenophore tip clearly trifid, with a pronounced middle denticle; solenomere long and flagelliform.

Remarks.

This new species seems to be restricted to Pahang State, southern Malay Peninsula within Malaysia (Map 2).

Species with a shortened gonopod femorite