Orthomorpha suberectoides, Likhitrakarn, Natdanai, Golovatch, Sergei I. & Panha, Somsak, 2014

Likhitrakarn, Natdanai, Golovatch, Sergei I. & Panha, Somsak, 2014, The millipede genus Orthomorpha Bollman, 1893 in Laos (Diplopoda, Polydesmida, Paradoxosomatidae), with descriptions of new species, ZooKeys 374, pp. 1-22 : 9-12

Orthomorpha suberectoides sp. n. Figs 7-9

Holotype

♂ (CUMZ), Laos, Attapu Province, Xaysetha District, Ban Lak No. 52, 224 m a.s.l., 15°09'24"N, 106°44'01"E, 16.10.2013, leg. C. Sutcharit.

Name.

To emphasize the apparent similarity to Orthomorpha suberecta Likhitrakarn, Golovatch & Panha, 2011; adjective.

Diagnosis.

This new species strongly resembles Orthomorpha suberecta , especially as regards the shape of the paraterga, but differs by a larger body, in the paraterga being broader, the metatergal tegument clearly rugose, and the pleurosternal carinae more strongly developed.

Description.

Length 35 mm (♂), width of midbody pro- and metazona 3.5 and 5.0 mm, respectively.

Coloration in alcohol, after one month of preservation, dark brown (Fig. 7 A–F), paraterga and epiproct pale pinkish or pallid, head and antennae brownish, venter and legs pale whitish to pale brown (Fig. 7 B–I).

All other characters as in Orthomorpha paviei , except as follows.

Antennae (Fig. 7A) reaching posterior end of body segment 3 when stretched dorsally. In width, head <collum <segment 2 <3 <4 <5-16, gently and gradually tapering thereafter. Collum with three transverse rows of setae: 4+4 in anterior, 2+2 in intermediate, and 4 +4 in caudal row; paraterga slightly declivous, broadly rounded and narrowly bordered, caudal corner pointed, dentiform, but not drawn behind rear margin (Fig. 7A, B).

Tegument shining and rugulose (Fig. 7 A–F), metaterga rather obviously rugose, leathery, with traces of tubercles/wrinkles; surface below paraterga microgranulate and rugulose. Postcollum metaterga with two transverse rows of setae: 2+2, mostly abraded setae in anterior (pre-sulcus) row, 3+3 in posterior (post-sulcus) one, these setae or their traces being borne on evident cones growing stronger laterally, until segment 6 visible only as insertion points, tuberculations gradually growing smaller thereafter. Tergal setae simple, rather long, about 1/3 of metatergal length, mostly abraded. Axial line traceable, especially clear on collum and following metaterga. Paraterga very strongly developed (Fig. 7 A–G), mostly slightly upturned, all lying faintly below dorsum, set at about half of midbody height, subhorizontal, in lateral view modestly enlarged in pore-bearing segments, thinner in poreless ones; shoulders broadly rounded, narrowly bordered, fused to callus; caudal corner almost or fully pointed, lying within rear tergal margin, after segment 16 drawn increasingly well beyond it, slightly curved mesad on segments 17-19 (Fig. 7 E–G). Calluses delimited by a sulcus only dorsally. Paraterga 2 broad, anterior edge convex, lateral edge with three small and acute denticles, the one near caudal corner being particularly small (Fig. 7A, B). Each following poreless segment with two incisions, each pore-bearing one with one, often evident incision in front of ozopore. Posterior edge of paraterga slightly concave, especially clearly so in segments 16-19. Ozopores evident, lateral, lying in an ovoid groove at about 1/4 of metatergite’s length in front of caudal corner. Transverse sulcus usually distinct (Fig. 7 A–F), complete on metaterga 5-19, incomplete on segment 4, narrow, not reaching bases of paraterga, ribbed at bottom. Stricture between pro- and metazona narrow, clearly ribbed at bottom down to base of paraterga (Fig. 7 A–F). Pleurosternal carinae complete crests with a sharp caudal tooth in segments 2-7, a very sharp, caudal tooth in segments 8-17, a small, rather sharp tooth in segment 18 (Fig. 7B, D, E). Epiproct (Fig. 7F, G) conical, flattened dorsoventrally, with two evident apical papillae, both latter directed ventrocaudally and acute at tip; pre-apical papillae small denticles lying close to tip. Hypoproct (Fig. 7G) roundly subtriangular, setiferous knobs at caudal edge evident and well-separated.

Sterna sparsely setose, without modifications; cross-impressions shallow; a paramedian pair of evident, fully separated, small, sternal cones between ♂ coxae 4 (Fig. 7H, I). A paramedian pair of evident tubercles in front of gonopod aperture. Legs moderately long and slender, midbody ones ca 1.0-1.1 times as long as body height, prefemora without modifications, ♂ tarsal brushes absent.

Gonopods (Figs 8, 9) with slender and long coxae, the latter with several setae distoventrally. Femorite about 3 times as long as prefemoral portion. Femorite slender, slightly curved, postfemoral portion demarcated by an oblique lateral sulcus. Solenophore with lamina lateralis clearly smaller than lamina medialis, tip distinctly bilobed, dorsal lobule larger; solenomere long and flagelliform.

Remarks.

According to the key in Likhitrakarn et al. (2011), this new species seems to be especially similar to Orthomorpha suberecta . The latter taxon has originally been found near Cave Suwannnakhuha, Suwannnakhuha District, Nong Bua Lamphu Province, northeastern Thailand ( Likhitrakarn et al. 2011), thus very far away (550 km) from the type locality of Orthomorpha suberectoides sp. n. Both these species are thus distinct not only morphologically (see Diagnosis), but also geographically.