Ovitamon lubang 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 lubang

description: Ovitamon lubang sp. nov.
(Figs. 2, 3 C, D)
Material examined. NMCR 25009, holotype male (29.7 × 22.7 mm), Philippines, Mindoro Occidental Province, Lubang Island, Barangay Sorville, Mount Ambolong, mid-mountain creek near Philippine Air Force Radar Station, coll R. V. Sison; 27 April 2001. Paratype: ZRC (ex NMCR 25033), 1 female (34.4 × 26.4 mm), same data as the holotype.
Diagnosis. Carapace with dorsal surface finely pitted or with rugosities; branchial regions gently convex; anterolateral margin strongly convex, with distinct cristae, adjacent areas with granules; epibranchial tooth small, blunt, distinctly separated from external orbital angle by small cleft; external orbital angle triangular, outer margin gently serrrated to granulated, cristate (Fig. 2 A, B); suborbital, pterygostomial regions gently rugose; posterior margin of epistome with prominent triangular median lobe with gently concave margins, about half width of margin (Fig. 2 B); chelipeds with outer surfaces distinctly rugose; fingers gaping slightly (Fig. 2 A, D); ambulatory legs rugose, dorsal margins of merus uneven, with scattered granules (Fig. 2 A, C); male sterno-abdomimal cavity reaching to imaginary line joining median part of bases of coxae of chelipeds (Fig. 2 C); male abdomen narrowly triangular (Fig. 2 C); G1 terminal segment subcylindrical, slightly longitudinally twisted, ca. 0.5 times length of subterminal segment; almost straight, tip relatively sharp; subterminal segment subquadrate, stout (Fig. 3 C, D).
Description of holotype male. Carapace transversely ovoid, dorsal surface finely pitted or with short rugosities, evenly convex; branchial regions gently convex; cervical groove shallow, broad; H-shaped median grooves distinct (Fig. 2 A). Frontal margin almost straight or slightly sinuous, cristate, bent downwards, forming low tranverse ridge (Fig. 2 B). Anterolateral margin strongly convex, cristate, adjacent areas with granules; epibranchial tooth small, blunt, distinctly separated from external orbital angle by small cleft (Fig. 2 A). Orbital margins gently sinuous, cristate, adjacent surface rugose (Fig. 2 B). Epigastric crista well defined, blunt, medially separated by short groove (Fig. 2 A). Postorbital ridge uneven, rounded, confluent with epibranchial tooth (Fig. 2 A). External orbital angle triangular, outer margin gently serrrated to granulated, gently concave, cristate (Fig. 2 A). Posterolateral margins sinuous, converging to gently convex posterior carapace margin, with some low oblique lateral ridges (Fig. 2 A). Suborbital, pterygostomial regions gently rugose (Fig. 2 B).
Buccal cavern squarish; third maxilliped with distinct flagellum, shorter than width of merus; sulcus on ischium shallow (Fig. 2 B). Epistome relatively wide, surface rugose, margins cristate; posterior margin of epistome with prominent triangular median lobe with gently concave margins, about half width of margin; lateral lobes low (Fig. 2 B).
Chelipeds unequal; outer surfaces rugose; merus relatively short, dorsal margin crenulated, rugose, but otherwise unarmed; carpus rounded with strong inner distal tooth, surface strongly rugose; major palm swollen, fingers gaping slightly; pollex with 2 subventral longitudinal grooves; dactylus with 3 shallow longitudinal grooves lined with pits; cutting margin with numerous denticles, low teeth (Fig. 2 A, D).
Ambulatory legs slender, long, surface rugose; with scattered stiff setae on margins; dorsal margins of merus uneven, with scattered granules; dactylus relatively long (Fig. 2 A).
Thoracic sternites smooth, with short setae only on margins; suture present between sternites 2, 3 gently convex towards buccal cavity; sternites 1, 2 completely fused, broadly triangular with sharp apex (Fig. 2 C). Sternoabdomimal cavity reaching to imaginary line joining median part of bases of coxae of chelipeds. Abdomen narrowly triangular; all somites free; telson longer than other somites, lateral margins almost straight, tip rounded; lateral margins of somite 3-6 gently convex to slightly concave (Fig. 2 C).
G1 subcylindrical, twisted; terminal segment ca. 0.5 times length of subterminal segment; terminal segment covered with spinules, stiff setae, almost straight, tip relatively sharp; distinctly demarcated from subterminal segment by wide cleft resembling collar, covered with very short stiff setae; subterminal segment subquadrate, stout, lateral margins lined with setae (Fig. 3 C, D). 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. Named after Lubang Island, the type locality. The name is used as a noun in apposition.
Remarks. The G1 structure of O. lubang sp. nov. is characteristic, with the G1 terminal segment long and straight, with the tip sharp and bent backwards (Fig. 3 C, D). In this regard, it is perhaps most similar to the condition seen in O. arcanum from Marinduque Island much farther east. The type locality of O. lubang sp. nov. is on Lubang Island (13°48’N 120°8'E) to the north of the island of Mindoro. The subterminal segment of O. lubang sp. nov. is nevertheless relatively straighter and the terminal segment is proportionately longer (Fig. 3 C, D) (versus gently subterminal segment sinuous in O. arcanum, Ng & Takeda 1992: fig. 1D-G). In addition, the anterolateral margin of O. lubang sp. nov. is distinctly cristate (Fig. 2 A, B), whereas it is almost smooth and rounded in O. arcanum (Ng & Takeda 1992: fig. 1A).
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 397-399, DOI: 10.11646/zootaxa.3619.3.8, http://zenodo.org/record/222698