Orangutana koropungoi Ng & Likhitrakarn, 2025

Ng, Ting Hui, Srisonchai, Ruttapon, Golovatch, Sergei I., Sutcharit, Chirasak, Panha, Somsak, Latim, Martinah & Likhitrakarn, Natdanai, 2025, A taxonomic study of millipede genera, Orangutana Golovatch, 1996 and Gigantomorpha Jeekel, 1963 (Diplopoda, Polydesmida, Paradoxosomatidae), with description of four new species from Sabah, Borneo, East Malaysia, European Journal of Taxonomy 987, pp. 221-248 : 240-244

Orangutana koropungoi Ng & Likhitrakarn sp. nov.

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Figs 11–13

Diagnosis

This new species strongly resembles Orangutana setosa , with which it appears to share most of the gonopodal characteristics. However, the new species is distinguished from O. setosa by its considerably larger body measuring 35.3 mm in length (vs smaller, 11–12 mm), the colour pattern which is black to dark brown with contrasting lighter red-brown paraterga ( Fig. 11A–H) (vs a uniformly pale yellowish brown to pale brown body), the longer antennae, in situ reaching body ring 4 ( Fig. 11A, C) (vs only past body ring 2), as well as the pleurosternal carinae being with complete crests, each with an evident, sharp, caudal denticle produced past the rear tergal margin on rings 2–4, gradually decreasing in size until rings 7 ( ♂) or 4 ( ♀) ( Fig. 11C, E, H) (vs completely absent), male sterna without modifications (vs male sterna show vestigial rounded knobs near the coxae starting with ring 8 onwards).

Etymology

“Koropungoi” is a vernacular name commonly used in the central Dusun language, which is spoken by people indigenous to the area around Gunung Alab and Mount Kinabalu, to denote a small millipede; noun in apposition.

Material examined

Holotype

MALAYSIA • ♂; Borneo, Sabah, Tambunan, Crocker Range Park , Gunung Alab Substation ; 5°49′17.6″ N, 116°20′29.4″ E; 1904 m a.s.l.; 19 Mar. 2023; T. H. Ng, T. S. Liew and F. Anthony leg.; BOR/MYR 44.

Paratypes

MALAYSIA • 1 ♀; Borneo, Sabah, Tambunan, Crocker Range Park , Gunung Alab Substation , along Minduk Sirung Trail ; 5°49′4.52″ N, 116°21′52″ E; 1918 m a.s.l.; 20 Mar. 2023; T. H. Ng, T. S. Liew and F. Anthony leg.; SP 14831 • 1 ♂; Borneo, Sabah, Ranau, Mesilau Nature Resort , Nepenthes Trail ; 6°02′45.4″ N, 116°35′49.1″ E; 1926 m a.s.l.; 26 Sep. 2023; T. H. Ng, F. Anthony, E.S.H. Quah, J. Dulipat, F.J. Chong, A. Joseph and C.L. Soo leg.; BOR/MYR 891 • 1 ♂; same data as for preceding; SP 14833 • 2 ♀♀; same data as for preceding; BOR/MYR 86, 88 • 1 ♀; same data as for preceding; SP 14834 • 2 ♀♀; Borneo, Sabah, Ranau, Mesilau Nature Resort , Tambang Gate ; 6°02′41.7″ N, 116°35′45.0″ E; 1922 m a.s.l.; 27 Sep. 2023; T. H. Ng, F. Anthony and F.J. Chong leg.; BOR/MYR 109, 110 • 1 ♀; Borneo, Sabah, Tambunan, Crocker Range Park , Gunung Alab Substation , Nepenthes Trail ; 5°49′21.4″ N, 116°20′30.5″ E; ca 1900 m a.s.l.; 26 Mar. 2024; T. H. Ng and F. Anthony leg.; BOR/ MYR 137 • 1 ♂; same data as for preceding; 27 Mar. 2024; BOR/MYR 138 • 1 ♂; Borneo, Sabah, Tambunan, Crocker Range Park , Gunung Alab Substation , along road up to substation; 5°49′14.52″ N, 116°21′52″ E; ca 1800 m a.s.l.; 27 Mar. 2024; T. H. Ng and F. Anthony leg.; BOR/MYR 144 .

Description

Length 30.6–32.5 mm ( ♂) or 26.8–34.8 mm ( ♀), width of midbody pro- and metazona 2.2–2.7 and 3.3–3.6 mm ( ♂) or 2.6–3.5 and 3.2–4.3 mm ( ♀), respectively.

Colouration of live animals blackish ( Fig. 11A); with contrasting pale red paraterga, antennae brown, venter and legs yellowish brown; colouration of alcohol material after seven months of preservation faded to castaneous brown; paraterga yellowish brown to pallid, antennae light, venter and legs light brown to light yellowish ( Fig. 11B–J).

Clypeolabral region and vertex sparsely setose, epicranial suture distinct. Antennae rather short ( Fig. 11A), reaching body ring 4 ( ♂, ♀) when stretched dorsally. In length, antennomere 2>3= 4> 5> 6>> 1=7. Interantennal isthmus ca 0.6 times diameter of antennal socket ( Fig. 12A). In width, head <collum <ring 3 <2<4 <5<6 <7–16 ( Fig. 11A–B), thereafter body gently and gradually tapering ( ♂, ♀). Collum with three transverse rows of strong setae: 3+3 anterior, 2+2 intermediate, and 4+4 posterior; caudal corner very broadly rounded, paraterga declined ventrad, not produced past rear tergal margin ( Fig. 11A, C).

Tegument rather smooth and shining, moderately rugulose only near transverse sulcus, prozona delicately shagreened, metaterga smooth and leathery, posterior halves often rugulose, surface below paraterga microgranulate ( Fig. 11A–F, H). Postcollum metaterga each with two uniform and transverse rows of setae: 2+ 2 in anterior, 3+ 3 in posterior row ( Fig. 11B–H); setae in posterior row borne on knobs, which become increasingly crestlike towards the telson, these reaching the transverse sulcus, but then gradually decreasing in size towards ring 19 ( Fig. 11B, D, F).

Tergal setae short, strong, slender, about 1/6 metatergal length. Axial line traceable both on pro- and metazona. Paraterga strongly developed ( Fig. 11A–F, H), subhorizontal, slightly upturned posteriorly, always lying high, at upper 1/3 midbody height, but remaining below dorsum; anterior edge well-developed, mostly nearly straight and narrowly bordered, fused to callus ( Fig. 11B, D); caudal corner of most paraterga very narrowly rounded, extending increasingly posterior tergal margin, slightly curved mesad on rings 14–19 ( Fig. 11F), posterior edge oblique ( Fig. 11D, F); paraterga very thin blunt blades in lateral view, a little thicker only on pore-bearing rings ( Fig. 11E). Calluses on paraterga delimited by a sulcus only dorsally. Paraterga 2 broad, anterior edge convex, lateral edge with four small acute denticles. Following poreless rings each with two small incisions at lateral edge ( Fig. 11B), one larger in anterior 1/3, the other smaller at posterior 1/3. Lateral edge of paraterga of following poreless rings with only one small incision near midway ( Fig. 11D).

Ozopores evident, lateral, each lying in an ovoid groove at about1/3 metatergal length in front of posterior edge of metaterga ( Fig. 11C, E). Transverse metatergal sulci usually distinct ( Fig. 11B, D, F), slightly incomplete on rings 4 and 18, complete and clearly visible on metaterga 5–17, rather deep, reaching the bases of paraterga, ribbed at bottom. Stricture between pro- and metazona rather wide, deep, beaded at bottom down to base of paraterga ( Fig. 11C–E). Pleurosternal carinae complete crests on rings 2–4, thereafter missing ( ♀) or broken into an anterior bulge and a caudal tooth, both increasingly reduced until ring 7, thereafter missing ( ♂) ( Fig. 11C, E, H).

Epiproct ( Fig. 11F–H) conical, flattened dorsoventrally, subtruncate, with two evident apical papillae directed caudally, both pointed at tip; pre-apical papillae small, but evident, lying close to tip. Hypoproct subtrapeziform ( Fig. 11G), small setigerous knobs at caudal edge well-separated and evident.

Sterna sparsely setose, without modifications; cross-impressions shallow; a sparsely setose, transverse lobe bearing a paramedian pair of evident, basally contiguous cones between male coxae 4 ( Fig. 11I– J). A paramedian pair of small, but evident tubercles in front of gonopod aperture. Legs long and slender, midbody legs ca 1.2–1.4 ( ♂) or 1.1–1.3 ( ♀) times as long as body height, prefemora without modifications, tarsal brushes present until legs 7.

Gonopods ( Figs 12–13) rather complex; coxa long and thick, subcylindrical, a little curved caudad, sparsely setose distoventrally ( Figs 12A–B, 14). Prefemoral part very short, densely setose about 1/5 as long as femoral part + postfemoral part ( Figs 12A–B, 14A–C). Femoral part long and slender, slightly curved distad, postfemoral– part demarcated by a very faint and oblique lateral sulcus ( Figs 12B, E–F, 13C); seminal groove running entirely mesally along the femoral part, solenomere (sl) flagelliform, fully sheathed by solenophore (sph). Solenophore hypertrophied composed of both well-developed lamina lateralis and lamina medialis. Lamina medialis (lm) well developed, thick and large, unciform, expanded apically, terminal tip clearly bifid, subterminal lobe smaller than terminal one, triangular in shape and pointed at tip; with a strong, sharp and denticulate process (d) at caudal edge ( Figs 12–13). Lamina lateralis (ll) thick and large, expanded apically, set lower than lamina medialis, both laminae supporting and sheathing most of solenomere ( Figs 12, 13A, C–D).

Remarks

This species was found at the Gunung Alab Substation ( Fig. 1C), which primarily consists of mossy, montane forest habitats and experiences limited periods of sunlight and extensive fog cover throughout the day ( Majuakim & Anthony 2016). One individual was found inside a small building which houses the office and guesthouse, adjacent to forest trails, and together with Gigantomorpha alabensis sp. nov., while the others were revealed under rotten logs along forest trails or by the roadside. The species was also found in the eastern part of the Kinabalu Park complex, at Mesilau ( Fig. 1C). Orangutana setosa , was reported from lowland areas in Sepilok, Sandakan, in eastern Sabah, approximately 180 km away from the type locality of the new species.