Orthomorpha isarankurai, 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 : 85-89

Orthomorpha isarankurai sp. n. Figs 9799

Holotype.

♂ (CUMZ), Thailand, Srakaeo Prov., Khao Chakan Distr., Khao Sam Sip, 13°40'36"N, 102°09'11"E, 03.09.2006, leg. S. Panha.

Paratypes.

2 ♂, 2 ♀ (ZMUC), 2 ♂, 2 ♀ (ZMUM), 4 ♂, 13 ♀, 2 juv. (CUMZ), same locality, together with holotype. 3 ♂, 1 ♀ (CUMZ), Chonburi Prov., Mueang Chon Buri Distr., Ang Hin Station, 13°20'21"N, 100°55'29"E, 01.11.1962, leg. K. Isarankura. 2 ♂, 1 ♀, 1 juv. (CUMZ), Chachengsao Prov., Phanom Sarakham Distr., Khao Hin Sorn, 04.09.2006, leg. C. Sutcharit. 1 ♂ (CUMZ), same Prov., Kaeng Hang Maeo Distr., Khao Sip Ha Chan National Park, 30.09.2009, leg. C. Sutcharit. 1 ♂ (CUMZ), Chanthaburi Prov., Mueang Chanthaburi Distr., Krathing Waterfall, ca 30 m, 16.09.2009, leg. N. Likhitrakarn.

Name.

Honours to Dr. Kumpol Isarankura, Professor of the Department of Biology of Chulalongkorn University, who collected some of the type specimens.

Diagnosis.

Differs in a peculiar colour pattern, coupled with narrow calluses of paraterga, and very broadly separated cones between ♂ coxae 4 (see also Key below).

Description.

Length mostly 29-34 (♂) or 33-36.5 mm (♀), width of midbody pro- and metazona 2.45-2.75 and 3.8-4.35 mm (♂), 2.9-3.35 and 4.35-4.85 mm (♀), respectively. One ♂ paratype (from Krathing Waterfall), 39.5 mm long, 3.6 and 5.5 mm wide on midbody pro- and metazona, respectively.

Coloration of alcohol material after long-term preservation castaneous brown with a pattern of contrasting whitish to yellow paraterga and epiproct, and mostly greyish-white posterior halves of postcollum metaterga; head and antennomeres 6 and 7 brown to dark brown; venter and a few basal podomeres light brown to yellow-brown, legs growing infuscate (brown) distally; tip of antenna pallid (Fig. 97A-G).

Clypeolabral region densely setose, vertex sparsely so, epicranial suture distinct. Antennae moderately long (Fig. 97B), surpassing end of body segment 3 (♂) or 2 (♀) dorsally. Head in width <collum <segment 4 <2 = 3 <5-16 (♂, ♀); thereafter body gently and gradually tapering. Collum with three transverse rows of setae: 3+3 anterior, 2+2 intermediate, and 2+2 posterior; a very faint incision laterally in posterior 1/3; caudal corner of paraterga pointed, beak-shaped, slightly declined ventrad, extended posteriad, but not surpassing rear tergal margin (Fig. 97A & B). Tegument smooth and shining, prozona very finely shagreened, metaterga smooth and delicately rugulose, leathery; surface below paraterga finely microgranulate. Postcollum metaterga with an anterior transverse row of 2+2, often abraded setae traceable at least as insertion points, a posterior row of 4+4 setae visible only on segment 19. Tergal setae long, slender, about 1/3 metatergal length. Axial line faint, barely traceable on metaterga (♂). Paraterga very strongly developed (Fig. 97A-G), especially well so in ♂, usually slightly upturned to subhorizontal, all lying high (at about 1/3 midbody height), albeit below dorsum; caudal corner almost completely to fully pointed, bent posteriad, especially strongly so on segments 16-18, either clearly (♂) or only very slightly extending beyond rear tergal margin (♀); paraterga very thin in lateral view, like blunt blades, a little thicker only on pore-bearing segments. Calluses delimited by a sulcus only dorsally, thin, especially so on poreless segments. Paraterga 2 broad, anterior edge straight, lateral edge with 2-3 small, but evident incisions in anterior 1/3; posterior edge slightly concave (Fig. 97B & C). Anterior edges of paraterga 3 and 4 evidently convex, of paraterga 5-18 nearly straight and slightly bordered. Lateral edge of paraterga 5-18 with a slight, but more evident incision/tooth in anterior 1/3 and a slightly smaller incision in posterior 1/3 only on pore-bearing segments. Posterior edge of paraterga evidently concave, usually bare, surface without traces of a lobule, on poreless paraterga more concave (Fig. 97A-D). Ozopores evident, lateral, lying in an ovoid groove at about 1/4 in front of caudal corner. Transverse sulcus usually very distinct (Fig. 97A, C & F), slightly incomplete on segments 4, 18 and 19 (not reaching bases of paraterga), complete on metaterga 5-17, deep, usually reaching bases of paraterga, at most faintly beaded at bottom, a little better developed in ♀. Stricture between pro- and metazona narrow, evidently beaded at bottom down to base of paraterga (Fig. 97A-F). Pleurosternal carinae com plete crests with a sharp caudal tooth on segments 2-4, a small, caudal, mostly sharp tooth on segments 5-7 (Fig. 97B, D & E), a very faint tubercle on segments 8-12 (♂) or 5-9 (♀). Epiproct (Fig. 97E-G) conical, flattened dorsoventrally, with two evident apical papillae, less being especially clear in ♂; tip subtruncate; pre-apical papillae evident, lying close to tip. Hypoproct (Fig. 97G) roundly subtriangular, setiferous knobs at caudal edge well-separated and evident.

Sterna delicately and sparsely setose, without modifications, but with a pair of very small, blunt, fully separated cones between ♂ coxae 4 (Fig. 97I & J). A pair of conspicuous rounded tubercles flanking anterior edge of gonopod aperture. Legs moderately long and slender, slightly incrassate in ♂, midbody ones ca 1.4-1.5 (♂) or 1.2-1.3 times (♀) as long as body height, prefemora without modifications, ♂ tarsal brushes present until legs of segment 10.

Gonopods (Figs 98 & 99) simple. Coxa long and slender, with several strong setae distodorsally. Prefemur densely setose, about half the length of femorite + “postfemoral” part. Femorite slender, curved and not enlarged distad, with a “postfemoral” part demarcated by an oblique lateral sulcus. Solenophore with a tridentate tip, middle denticle being especially small; solenomere long, flagelliform, a short tip exposed.

Remark.

This new species is rather widespread in eastern Thailand (Map 2).