Orthomorpha efefai Likhitrakarn, 2025

Likhitrakarn, Natdanai, Golovatch, Sergei I., Thi, Sothearen, Sophea, Chhin, Lou, Vanny, Sinovas, Pablo, Jeratthitikul, Ekgachai, Pholyotha, Arthit, Siriwut, Warut, Srisonchai, Ruttapon, Panha, Somsak & Sutcharit, Chirasak, 2025, Review of the millipede genus Orthomorpha Bollman, 1893 (Diplopoda, Polydesmida, Paradoxosomatidae) in Cambodia, with new records and descriptions of three new species, ZooKeys 1251, pp. 251-274 : 251-274

publication ID	https://doi.org/10.3897/zookeys.1251.158776
publication LSID	lsid:zoobank.org:pub:9DEED866-2FE6-430F-BB49-42CC7EF0A4DD
DOI	https://doi.org/10.5281/zenodo.17094774
persistent identifier	https://treatment.plazi.org/id/219CCE65-6B4F-51F4-8150-7E964467422A
treatment provided by	ZooKeys by Pensoft
scientific name	Orthomorpha efefai Likhitrakarn
status	sp. nov.

Treatment

Orthomorpha efefai Likhitrakarn sp. nov.

Figs 5 A, B View Figure 5 , 6 View Figure 6 , 7 View Figure 7 , 8 View Figure 8

Material examined.

Holotype: ♂ ( CUMZ -PD 0035 ), Cambodia, Battambang Province, Banan District, Chheu Teal, outside Neang Romsay Sak Cave (locality code C 101), ca 50 m a. s. l., 12°57'34"N, 103°06'32"E, 31. 07. 2024, leg. R. Srisonchai. GoogleMaps Paratypes: 1 ♀ ( CUMZ -PD 0035 ), same data, together with holotype GoogleMaps . 1 ♂, 3 juveniles ( CUMZ -PD 0036 ), Cambodia, Battambang Province, South-West Battambang, Phnom Romsay Sak , cave, 25 m a. s. l., 12°57'28"N, 103°06'32"E, 19. 07. 2017, leg. P. Jäger and S. Münnich GoogleMaps .

Etymology.

The species name ‘ efefai’ is a phonetic spelling representation of the Fauna and Flora Cambodia (formerly known by the acronym FFI). This new species is named in honour of their passionate commitment to protecting Earth’s biodiversity and acknowledges FFI Cambodia for supporting our team to explore the rich biodiversity of the country. When pronounced, ‘ efefai’ is with the ‘ e’ and ‘ a’ being silent.

Diagnosis.

This new species seems to be particularly similar to Orthomorpha parasericata Likhitrakarn, Golovatch & Panha, 2010 , a species known only from Surat Thani and Phang Nga provinces in southern Thailand, in having likewise broad, contrastingly lighter-colored paraterga, coupled with a stout gonopod telopodite and a bifid solenophore. However, it clearly differs by its smaller body size ( 28.4–33 mm long and 4.2–4.9 mm wide in males, 32.5 mm long and 4.6 mm wide in females, vs 32–37 mm long and 4.8–5.0 mm wide in males, 34–37 mm long and 4.8–5.3 mm wide in females of O. parasericata ), as well as by the shape of the solenophore apex. Additionally, tarsal brushes are present until ♂ legs of ring 9 in the new species, whereas in O. parasericata , they are present only until ♂ legs of ring 5.

Orthomorpha efefai sp. nov. can also be distinguished from the sympatric O. tergoaurantia sp. nov., with which it shares a superficially similar gonopod structure. The key differences lie in the somatic characters. The metaterga in O. efefai sp. nov. are distinctly rugulose-tuberculate, bearing two rows of setiferous cones, especially on the anterior body rings (Fig. 6 A, B View Figure 6 ). In contrast, the metaterga of O. tergoaurantia are mostly smooth and leathery, with setiferous knobs being far less pronounced (Fig. 2 A – F View Figure 2 ). The male tarsal brushes extend until the legs of ring 9 in O. efefai sp. nov., but are far more extensive in O. tergoaurantia sp. nov., persisting until the legs of ring 17. Additionally, the caudal tooth of the pleurosternal carinae is traceable until ring 16 in O. efefai sp. nov., but only until rings 7 or 8 in O. tergoaurantia sp. nov. (Fig. 2 B, D View Figure 2 ). Although broadly similar, the solenophore tip in O. efefai sp. nov. is distinctly bifid (Figs 7 View Figure 7 , 8 View Figure 8 ), while in O. tergoaurantia sp. nov. it is trifid, with a small but clear middle prong (Figs 3 View Figure 3 , 4 A, C – F View Figure 4 ).

Description.

Length 28.4–31.8 mm ( ♂), 32.5 mm ( ♀), width of midbody pro- and metazona 2.6–2.7 and 4.2–4.3 mm ( ♂) or 3.3 and 4.6 mm ( ♀), respectively.

Coloration of live animals blackish (Fig. 5 A, B View Figure 5 ), with contrasting reddish pink or bright pink paraterga and epiproct, posterior halves of metaterga on rings 16–1 and antennae blackish, legs brown; coloration of alcohol material after 10 months of preservation faded to uniformly dark brown (Fig. 6 A – G View Figure 6 ) with contrasting bright pink or pale pinkish paraterga and epiproct, legs brown to light grey-brown.

Clypeolabral region and vertex sparsely setose, epicranial suture distinct. Antennae long (Fig. 5 B View Figure 5 ), extending past ring 3 ( ♂) or reaching to ring 3 ( ♀) when stretched dorsally. In width, head <collum <ring 3 <4 <2 <5 <6 <7–15 (Fig. 6 A View Figure 6 ), thereafter body gently and gradually tapering. Collum with three transverse rows of strong setae: 3 + 3 anterior, 2 + 2 intermediate, and 3 + 3 posterior; a very faint incision laterally in posterior 1 / 3; caudal corner of paraterga pointed, dentiform, paraterga declined ventrad, not drawn past rear margin.

Tegument of metaterga shining, rugulose-tuberculate, especially so on several front metaterga; prozona very finely shagreened, metazona below paraterga faintly rugulose (Fig. 6 A – F View Figure 6 ). Metaterga 2–5 with two rows of 2 + 2 anterior and 3 + 3 setiferous cones, usually slightly smaller cones in anterior (pre-sulcus) row and more evident ones laterally in posterior row (Fig. 6 A, B View Figure 6 ); thereafter same pattern, but traceable only as insertion points in anterior row and as minute knobs gradually increasingly obliterate to become nearly absent from ring 10 onward. Tergal setae short, simple, slender, often abraded, about 1 / 4 metatergal length. Axial line traceable, especially clear on collum and following few metaterga. Paraterga very strongly developed (Fig. 6 A – F View Figure 6 ), broad, all lying below dorsum (at about 1 / 4 body height), mostly subhorizontal, slightly upturned on rings 2–5, in lateral view moderately enlarged on pore-bearing rings, thinner on poreless ones (Fig. 6 B, D, E View Figure 6 ); anterior margin well-developed, mostly nearly straight and narrowly bordered, fused to callus; caudal corner of most of paraterga very narrowly rounded, increasingly drawn past tergal margin, slightly curved mesad on rings 15–19 (Fig. 6 B, D, E View Figure 6 ). Calluses on paraterga delimited by a sulcus only dorsally. Paraterga 2 broad, lateral edge with two small, but evident incisions, one in anterior 1 / 3, the other in posterior 1 / 3. Paraterga 3 and 4 each with an evident incision in anterior 1 / 3 at lateral margin (Fig. 6 A View Figure 6 ). Lateral margins of following paraterga with two small incisions, one at midway, the other in posterior 1 / 3, the other at midway, caudal incision being smaller on pore-bearing rings (Fig. 6 A, C, F View Figure 6 ). Posterior margin of paraterga concave, especially clearly so in rings 15–19. Ozopores evident, lateral, lying in an ovoid groove at about 1 / 3 metatergal length in front of posterior edge of metaterga (Fig. 6 B, D, E View Figure 6 ). Transverse sulcus distinct (Fig. 6 A – F View Figure 6 ), slightly incomplete on ring 2, complete and clearly visible on metaterga 3–18, shallow, reaching the bases of paraterga, arcuate, faintly beaded at bottom. Stricture between pro- and metazona rather wide, deep, beaded at bottom down to base of paraterga (Fig. 6 A, C, F View Figure 6 ). Pleurosternal carinae complete crests on rings 2–4, following rings 5–7 (8) each broken into an anterior bulge and a sharp caudal tooth, the latter gradually reduced in size to a small tooth until ring 16, thereafter missing ( ♂, ♀) (Fig. 6 B, C, E View Figure 6 ).

Epiproct (Fig. 6 E – G View Figure 6 ) conical, flattened dorsoventrally, subtruncate, with two evident apical papillae directed ventrocaudally (Fig. 6 E, G View Figure 6 ); pre-apical papillae small, but evident, lying close to tip. Hypoproct subtrapeziform (Fig. 6 G View Figure 6 ), 1 + 1 small setiferous knobs at caudal edge well-separated and evident.

Sterna sparsely setose, without modifications; cross-impressions rather deep; a paramedian pair of evident, fully separated, setose cones between ♂ coxae 4 (Fig. 6 H, I View Figure 6 ). A conspicuous ridge in front of gonopod aperture. Legs moderately long and slender, midbody ones ca 1.0–1.2 ( ♂) (Fig. 5 B View Figure 5 ) or 0.9–1.1 times ( ♀) as long as body height, prefemora without modifications, ♂ tarsal brushes present until leg 9.

Gonopods simple and suberect (Figs 7 View Figure 7 , 8 View Figure 8 ). Coxite ( cx) long and slender, slightly curved caudally, rather densely setose distodorsally (Figs 7 B, C View Figure 7 , 8 A, B View Figure 8 ). Prefemoral part ( pfe) densely setose, as usual, less than half the length of acropodite (femoral + postfemoral parts) (Fig. 7 B, C View Figure 7 ). Femoral part ( fe) slender, slightly curved and slightly enlarged distad, with a postfemoral part demarcated by an oblique lateral sulcus (Figs 7 A, B View Figure 7 , 8 B, E View Figure 8 ). Solenophore ( sph) with an evidently bifid tip, with a subterminal lobule (Figs 7 View Figure 7 , 8 A – E View Figure 8 ) and a spiniform apical lobule (Figs 7 View Figure 7 , 8 A – F View Figure 8 ); solenomere ( sl) long and flagelliform (Figs 7 A, B View Figure 7 , 8 A, C, E View Figure 8 ).