Orthomorpha tuberculifera, 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 : 19-23

Orthomorpha tuberculifera sp. n. Figs 1315

Holotype.

♂ (CUMZ), Thailand, Nakhon Ratchasima Prov., Pakchong Distr., Khao Rup Chang, ca 420 m, 14°31'33"N, 101°21'36"E, 26.04.2009, leg. S. Panha, R. Chanabun & N. Likhitrakarn.

Paratypes.

2 ♂, 2 ♀ (ZMUC), 2 ♂, 2 ♀ (ZMUM), 14 ♂, 21 ♀ (CUMZ), same data as holotype. 1 ♂ (CUMZ), same Distr., Klang Dong Restaurant, ca 360 m, 14°09'10"N, 101°18'35"E, 01.04.2011, leg. R. Chanabun.

Name.

To emphasize the evident metatergal tuberculation.

Diagnosis.

The new species differs in evidently tuberculated metaterga, coupled with only a small anterolateral incision on paraterga and a bifid gonopod tip (see also Key below).

Description.

Length 24-32 mm (♂), 27-34 mm (♀), width of midbody pro- and metazona 2.6-3.3 and 4.5-5.2 mm (♂), 2.9-4.0 and 4.5-5.5 mm (♀), respectively Coloration of live animals blackish, paraterga and epiproct contrasting creamy orange, legs and venter brownish to pale brown (Fig. 13A); coloration of alcohol material after preservation faded to dark castaneous brown, paraterga (marbled at base), metatergal tubercles, middle region of prozona, venter, epiproct, and several basal podomeres more flavous, pale pinkish, brownish or pale yellow (Fig. 13B-J).

Clypeolabral region densely setose, vertex bare, epicranial suture distinct. Antennae short, poorly clavate (Fig. 13A), extending behind segment 2 (♂) or until midway of segment 2 (♀) dorsally.

Head in width << collum <segments 3-4 <2 = 5-16 (♂), or head <collum <segments 3-4 <2 <5-16 (♀); thereafter body gently and gradually tapering. Collum with three transverse rows of medium-sized setae, 4+4 anterior, 2+2 intermediate, and 2+2 posterior, all borne on very evident tubercle, these being especially high in caudal row; paraterga slightly declivous, broadly rounded and narrowly bordered, caudal corner a minute knob, not extending behind tergal margin (Fig. 13B & C). Tegument rather poorly shining, prozona very finely shagreened, metaterga coriaceous, roughly rugose and granulate, below paraterga rugulose. Postcollum metaterga with two transverse rows of short, mostly abraded setae borne on evident tubercles: 2+2 in front (pre-sulcus) row on smaller tubercles and 3+3 in caudal (postsulcus) row on higher, sharper and dorsocaudally inclined tubercles (Fig. 13B-F). Metatergal tubercles especially high on collum and several following segments, growing increasingly lower towards segment 19. Axial line clear, especially so on metaterga. Paraterga very strongly developed (Fig. 13A-H), especially well so in ♂, mostly subhorizontal to faintly declivous, always lying below dorsum, set at about 1/3-1/4 midbody height; shoulders well-developed, mostly straight; caudal tips of paraterga nearly pointed to pointed, always extending behind tergal margin, increasingly well pointed and often bent mesad on paraterga (14-)19. Calluses delimited by a sulcus both dorsally and ventrally, especially deeply so dorsally, rather broad, with three more or less evident lateral incisions on callus 2 and two strong indentations on following segments (Fig. 13B, D & F). Posterior edge of paraterga always evidently concave, more strongly so on segments 16-19 (Fig. 13F). 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 2-18, incomplete on metaterga 2-4, complete and reaching bases of paraterga on following segments, beaded at bottom, deep (Fig. 13B, D & F). Stricture between pro- and metazona deep, evidently ribbed at bottom down to base of paraterga. Pleurosternal carinae large, roughly granulate crests with a distinct tooth both frontally and caudally, complete on segments 2-9 (♂) or 2-8 (♀), thereafter split into both front and caudal teeth, the former turning into bulges until segment 13(14), the latter tooth gradually reduced until segment 18 (♂) or 17 (♀), much more strongly developed in ♂ than in ♀ (Fig. 13C, E & H). Epiproct (Fig. 13F & G) conical, rather short, flattened dorsoventrally, with two very evident (♂) or rather small, sharp, apical teeth (♀) directed ventrocaudally; pre-apical papillae evident, located close to tip. Hypoproct (Fig. 13G) roundly subtriangular, setiferous knobs at caudal edge clear and well-separated.

Sterna delicately and rather densely setose; a paramedian pair of evident, fully separated, setose cones between ♂ coxae 4 (Fig. 13I & J). A paramedian pair of small tubercles in front of gonopod aperture. Legs moderately long and slender, almost not incrassate in ♂, midbody ones ca 1.2-1.3 (♂) or 0.8-0.9 times (♀) as long as body height, prefemora without modifications, ♂ tarsal brushes present only on ♂ legs 1-3, thereafter gradually thinning out.

Gonopods (Figs 14 & 15) simple. Coxa long and slender, with several strong setae distodorsally. Prefemoral part densely setose, about 3 times shorter than femorite + “postfemoral” part. Femorite slender, suberect to slightly curved, nearly not enlarged distad, with a “postfemoral” part demarcated by an oblique lateral sulcus. Solenophore tip either very faintly bidentate, with both denticles being subequal, or a nearly smooth lobe; solenomere long and flagelliform.

Remarks.

There are two further populations which we regard as representing the same new species. One of the populations (15 ♂, 3 ♀ (CUZM), non-types) comes from Thailand, Lop Buri Prov., Khok Samrong Distr., Khao Wong Phrachan Temple, 14°58'0"N, 100°41'49"E, 07.06.2008, leg. C. Sutcharit. The other one (1 ♂, 2 ♀ (CUZM), non-types) comes from Thailand, Saraburi Prov., Kaeng Khoi Distr., Kaeng Khoi, 14°58'N, 100°59'E, 08.09.2007, leg. S. Panha. All three localities are situated about 100-200 km from one another, west, north and northwest of the Sankamphaeng Mountain Range, Khao Yai National Park within the same hilly area (Map 2).