Ovitamon baloy Manuel-Santos & Ng, 2013, sp. nov.
Creators: name: Manuel-Santos, Marivene R.
name: Ng, Peter K. L.
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Potamidae
Ovitamon
Ovitamon baloy

description: Ovitamon baloy sp. nov.
(Figs. 1, 3 A, B)
Material examined. NMCR 15007, holotype male (19.5 × 14.7 mm), Philippines, Panay island, Antique, Valderrama, Mount Baloy, 1340 m asl, coll. M. R. Manuel, October 1989. Paratypes: ZRC (ex NMCR 25034), 1 male (18.0 × 13.6 mm), NMCR 25034, 1 female (18.1 × 14.3 mm), same data as holotype.
Diagnosis. Carapace with dorsal surface smooth or finely pitted; branchial regions prominently swollen; anterolateral margin strongly convex, with very low, weak cristae; epibranchial tooth low, blunt, not distinctly separated from external orbital angle by notch or fissure; external orbital angle broadly triangular, blunt, outer margin smooth, gently concave, cristate (Fig. 1 A, B); suborbital, pterygostomial regions smooth; posterior margin of epistome with triangular median lobe about one-third width of margin (Fig. 1 B); chelipeds with outer surfaces almost smooth, fingers prominently gaping in adult male (Fig. 1 A, D); ambulatory legs smooth, dorsal margin of merus almost smooth (Fig. 1 A, C); male sterno-abdomimal cavity reaching to imaginary line joining anterior edges of coxae of chelipeds; male abdomen broadly triangular (Fig. 1 C); G1 relatively stout; terminal segment ca. 0.3 times length of subterminal segment, cylindrical, gently twisted longitudinally, gently curved, tip rounded (Fig. 3 A, B).
Description of holotype male. Carapace transversely ovoid, dorsal surface smooth or finely pitted, evenly convex; branchial regions prominently swollen; cervical groove distinct, shallow, broad; median grooves Hshaped, distinct (Fig. 1 A). Frontal margin gently sinuous, cristate, bent downwards, forming low transverse ridge (Fig. 1 B). Anterolateral margin strongly convex, with very low, weak cristae; epibranchial tooth very low, blunt, almost confluent with epigastric margin, not distinctly separated from external orbital angle (Fig. 1 A, B). Orbital margins gently sinuous, cristate. Epigastric cristae not well defined, low, separated by shallow Y-shaped groove (Fig. 1 A). Postorbital cristae uneven, low, confluent with epibranchial tooth (Fig. 1 A). External orbital angle broadly triangular, blunt, outer margin smooth, gently concave, cristate (Fig. 1 A). Posterolateral margins sinuous, converging to convex posterior carapace margin, no oblique lateral ridges discernible (Fig. 1 A). Suborbital, pterygostomial regions smooth (Fig. 1 B).
Buccal cavern quadrate; third maxilliped with distinct flagellum, slightly shorter than width of merus; sulcus on ischium very shallow (Fig. 1 B). Epistome relatively wide, covered with short thick setae, margins cristate; posterior margin of epistome with triangular median lobe with concave margins, about one-third width of margin; lateral lobes low (Fig. 1 B).
Chelipeds unequal; outer surfaces mostly smooth; merus relatively short, dorsal margin crenulated but otherwise unarmed; carpus rounded with strong inner distal tooth; major palm swollen, fingers prominently gaping; pollex with subventral longitudinal groove; dactylus with 3 shallow longitudinal grooves lined with pits; cutting margin with small denticles to almost smooth (Fig. 1 A, D).
Ambulatory legs slender, long, smooth; with some stiff setae on margins; dorsal margin of merus almost smooth; dactylus relatively long (Fig. 1 A).
Thoracic sternites smooth, with setae only on margins; suture present between sternites 2, 3 gently convex towards buccal cavity; sternites 1, 2 completely fused, broadly triangular with apex long, sharp (Fig. 1 C). Sternoabdomimal cavity reaching to imaginary line joining anterior edges of coxae of chelipeds (Fig. 1 C). Abdomen broadly triangular; all somites free; telson longer than other somites, lateral margins vaguely sinuous, tip rounded; lateral margins of somite 3–6 straight to gently convex (Fig. 1 C).
G1 relatively stout; terminal segment ca. 0.3 times length of subterminal segment, cylindrical, gently twisted longitudinally, gently curved towards median part of thoracic sternum, densely covered with spinules, hooked spines, hooked stiff setae, tip rounded; collar separating terminal, subterminal segments narrow, not swollen; subterminal segment with margins setose (Fig. 3 A, B). G2 long, sinuous; flagellum about half length of basal segment, proximal part broadly dilated.
Female. The female abdomen completely covers the thoracic sternum. The vulvae are relatively large, without a visible operculum.
Etymology. The name comes from Baloy, the mountain where this species was collected. The name is used as a noun in apposition.
Colour in life. Branchial regions reddish-violet, margins orange; gastric region brownish purple; chelipeds purple; spines on legs orange.
Remarks. Two other species of Ovitamon, O. tomaculum and O. cumingii, are known from the island of Panay in central Philippines. The most significant difference between O. tomaculum and O. baloy sp. nov. is the structure of the G1. In O. baloy sp. nov., the G1 is proportionately much stouter (especially the subterminal segment), with the terminal segment relatively shorter, and the tip is broadly rounded (Fig. 3 A, B) (G1 relatively more slender overall with the terminal segment distinctly tapering in O. tomaculum, cf. Ng & Takeda 1992: fig. 3E-H). These differences are substantial and cannot be accounted for by size-associated changes or individual variation. The holotype male of O. cumingii is dried and the important G1 structure is not available for examination (Ng & Takeda 1993).
The carapaces of the two species, however, are very different, with that of O. baloy sp. nov., relatively rounder and smoother, with the anterolateral margin rounded and almost smooth with the cristae very low (Fig. 1 A, B) (versus carapace proportionately broader, with lateral regions rugose and prominent anterolateral cristae, cf. Ng & Takeda 1993: fig. 1A, B). In any case, the type locality of O. baloy sp. nov. (Mount Baloy, 11°8'56"N 122°15'9"E) is 100 km northwest of Guimaras Island (ca. 10°35ʹN 12°236ʹE), the type locality of O. cumingii.
description: Published as part of Manuel-Santos, Marivene R. & Ng, Peter K. L., 2013, Two new species of Ovitamon Ng & Takeda, 1992 (Crustacea: Brachyura: Potamidae) from the Philippines, pp. 394-400 in Zootaxa 3619 (3) on pages 395-397, DOI: 10.11646/zootaxa.3619.3.8, http://zenodo.org/record/222698