Gigantomorpha mesilauensis Ng & Likhitrakarn, 2025

Gigantomorpha mesilauensis Ng & Likhitrakarn sp. nov.

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Figs 5–7 View Fig View Fig View Fig

Diagnosis

This new species closely resembles G. sayapensis sp. nov., especially in that both species have the gonopod tip small bifid without distinct branching. However, it is distinguished by the less strongly bordered paraterga ( Fig. 5A, C, F View Fig ) (vs strongly bordered; Fig. 8B, D, F View Fig ), the sternal cones present only between male coxae 4 (vs between both male coxae 4 and 5), and the gonopodal lamina lateralis (ll) and lamina medialis (lm) subequal in length, long, and slender, slightly narrowed apically ( Figs 6A, C, E View Fig , 7A–B View Fig ) (vs lamina medialis (lm) larger and expanded apically, Figs 3A–D View Fig , 4A–B View Fig ).

Etymology

To emphasise the type locality, adjective in feminine gender.

Material examined

Holotype

MALAYSIA • ♂; 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 90 .

GoogleMaps

Paratypes

MALAYSIA • 1 ♂; same data as for holotype; SP 14837 • 1 ♂; same data as for holotype; BOR/MYR 85 GoogleMaps • 1 ♂; 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 111 GoogleMaps • 1 ♀; same data as for preceding; SP 14838 GoogleMaps • 1 ♀; same data as for preceding; BOR/MYR 108 GoogleMaps • 1 ♂; Borneo, Sabah, Ranau, Kinabalu Park , Mount Tambuyokon ; 6°12′24.5″ N, 116°40′13.9″ E; 2012 m a.s.l.; 11 May 2023; T.H. Ng, F. Anthony and T.S. Liew leg.; SP 14839 GoogleMaps • 1 ♀; Borneo, Sabah, Ranau, Kinabalu Park , Mount Tambuyokon ; 6°12′22.5″ N, 116°40′06.7″ E; 2052 m a.s.l.; 11 May 2023; T.H. Ng, F. Anthony and T.S. Liew leg.; BOR/MYR 78 GoogleMaps • 1 ♀; Borneo, Sabah, Ranau, Kinabalu Park , Mount Tambuyokon ; 6°12′45.5″ N, 116°40′51.7″ E; 1398 m a.s.l.; 11 May 2023; T.H. Ng, F. Anthony and T.S. Liew leg.; SP 14840 GoogleMaps .

GoogleMaps

Description

Length 35.4–41.3 mm (♂) or 33.5–39.5 mm (♀), width of midbody pro- and metazonae 2.4–2.8 and 3.6–4.2 mm (♂) or 2.3–3.3 and 3.9–4.4 mm (♀), respectively. Holotype 37.4 mm long, and 2.7 and 4.1 mm wide on midbody pro- and metaterga, respectively.

Colouration of alcohol material after one year of preservation dark brown or castaneous brown with a pattern of contrasting yellowish brown paraterga and epiproct ( Fig. 5A–G View Fig ); antennae brown to light brown ( Fig. 5B View Fig ); venter and legs light brown to light yellowish ( Fig. 5B, E–I View Fig ).

Clypeolabral region and vertex sparsely setose, epicranial suture distinct.Antennae rather short ( Fig. 5B View Fig ), reaching body ring 3 (♂, ♀) when stretched dorsally. In length, antennomere 3 =2> 5>4 =6>> 1=7. Interantennal isthmus ca 0.6 times diameter of antennal socket ( Fig. 8B View Fig ). In width, head <collum <ring 3<2<4<5<6<7–16 ( Fig. 5A View Fig ), 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. 5A–B View Fig ).

Tegument rather smooth and shining, prozona delicately shagreened, metaterga smooth and leathery, posterior halves faintly rugulose, surface below paraterga microgranulate ( Fig. 5A–F View Fig ).

Postcollum metaterga each with two transverse rows of setae: an anterior transverse row with 2+2, often abraded setae traceable at least as insertion points, and a posterior row with 4(5)+4(5) setae borne on low, oblong, rounded tubercles or minute knobs with insertion points of mostly abraded setae. Tergal setae rather short, strong, slender, about 1/4 metatergal length. Axial line traceable both on pro- and metazona. Paraterga very strongly developed ( Fig. 5A–G View Fig ), especially well so in males, subhorizontal to mostly slightly upturned, lying above dorsum or slightly above dorsum, thin in lateral view, like blunt blades, a little thicker only on pore-bearing rings, on postcollum rings extending increasingly beyond dorsum, especially so in rings 17–19; anterior edge broadly rounded and narrowly bordered, fused to callus; caudal corner almost completely to fully pointed, always extending past rear tergal margin, bent posteriad on rings 17–19; posterior edge oblique ( Fig. 5A, C, F View Fig ). Calluses on poreless paraterga delimited by a sulcus only dorsally, but on pore-bearing rings paraterga both dorsally and ventrally. Paraterga 2 broad, lateral edge with three small acute denticles, one at midway, the other two each at posterior 1/3 ( Fig. 5A View Fig ). Paraterga 3 and 4 each with two similar evident incisions, one at midway, the other in posterior 1/3 ( Fig. 5A View Fig ). Following poreless rings with two evident incisions, one at midway, the other in posterior 1/3, caudal incision in pore-bearing rings smaller or gradually reduced in posterior rings ( Fig. 5D, F View Fig ). Ozopores evident, lateral, each lying in an ovoid groove at about 1/3 metatergal length in front of posterior edge of metaterga ( Fig. 5C–E View Fig ).

Transverse sulcus usually distinct ( Fig. 5A, C, F View Fig ), complete and visible on metaterga 5–18, rather deep and narrow, reaching the bases of paraterga, linear, ribbed at bottom. Stricture between pro- and metazona rather wide, deep, ribbed at bottom down to base of paraterga ( Fig. 5A, C, F View Fig ). Pleurosternal carinae complete crests only on rings 2 and 3 ( Fig. 8B View Fig ), each with an evident sharp denticle caudally, thereafter increasingly reduced until ring 8 (♂) or 7 (♀).

Epiproct ( Fig. 5E–G View Fig ) conical, flattened dorsoventrally, subtruncate, with two evident apical papillae directed caudally, both pointed at tip; pre-apical papillae evident, lying close to tip. Hypoproct subtrapeziform ( Fig. 5G View Fig ), small setigerous knobs at caudal edge well-separated and evident.

Sterna separsely setose, without modifications; cross-impressions shallow; two large and long, fully separated, sparsely setose, sternal cones between male coxae 4 ( Fig. 5H–I View Fig ). A paramedian pair of small tubercles in front of gonopod aperture. Legs long and slender, midbody ones ca 1.3–1.5 (♂) or 1.1–1.3 (♀) times as long as body height; prefemora without modifications; tarsal brushes present until legs of ring 17.

Gonopods ( Figs 6–7 View Fig View Fig ) simple; coxa long and thick, subcylindrical, a little curved caudad, sparsely setose distoventrally ( Figs 6A–B View Fig , 7A–B View Fig ). Prefemoral part short, densely setose as usual, about 1/4 as long as femoral part + postfemoral part ( Fig. 7A–B View Fig ). Femoral part long and slender, slightly expanded distad, curved, postfemoral part demarcated by an oblique lateral sulcus ( Figs 6A–B, D, F View Fig , 7A–B View Fig ); seminal groove running entirely mesally along fermorite, solenomere (sl) flagelliform, fully sheathed by solenophore (sph). Both lamina lateralis (ll) and lamina medialis (lm) well developed, subequal in length, long and slender ( Figs 6A, C, E View Fig , 7B View Fig ). Lamina medialis (lm) with tip clearly bifid ( Fig. 7A View Fig ).

Remarks

This species was collected on rocks and vegetation, under rotten branches or logs, in lower montane forest habitats in the Mesilau and Mount Tambuyokon areas in the eastern part of the Kinabalu Park complex ( Fig. 1C View Fig ).