Selwynia punctata Ng & Rahayu, 2016, n. sp.
Creators: name: Ng, Peter K. L.
name: Rahayu, Dwi Listyo
Publisher: name: Zenodo
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Pilumnidae
Selwynia
Selwynia punctata

description: Selwynia punctata n. sp.
(Figs. 13–16)
Material examined. Holotype: ovigerous female (7.0 × 4.0 mm) (UF), BMOO 15737, east side of Opunohu Bay, about 1 km north of Criobe, near white tower in water, Moorea, northwest of Tahiti, 17.51012ºS 149.85129ºE, French Polynesia, 3–11 m, coll. D. Uyeno & A. Anker, 19 November 2010. Paratype: 1 male (4.3 × 3.3 mm) (ZRC 2015.280), BMOO 15730, same data as holotype.
Description (female holotype). Carapace (Figs. 13 B, 14A) oval, about 1.6 broader than long; dorsal surface smooth, region poorly demarcated, flattened to gently concave on mesogastric region, pit on each hepatic region. Front (Figs. 13 C, 14B) strongly deflexed, medially concave in dorsal view. Orbital margin (Figs. 13 C, 14B) entire, slightly narrower distally, narrow gap between cornea, external orbital angle. Anterolateral margin entire, convex laterally, not cristate, continuous with posterolateral margin. Epistome (Fig. 14 B) short, medially sunken. Antennule (Fig. 14 B) folding transversely in fossa. Antenna (Fig. 14 B) with stout basal antennal article, not reaching distolateral angle of carapace; antenna enters orbit. Ocular peduncles (Fig. 14 B) movable, short, stout, subconical, cornea small, well pigmented.
Third maxillipeds (Fig. 13 C) covering four-fifths of buccal cavern when closed; ischium 1.4 times length of merus; exopod slender, reaching midlength of merus; flagellum long.
Thoracic sternites 1, 2 fused, sternites 2/3 separated by deep furrow, sternites 3/4 demarcated by shallow ridge; sternites 4–8 laterally demarcated by shallow sutures; sutures between sternites 4/5, 6/7 longer than others, vulva rounded, on distal three-fourths of sternite 6.
Chelipeds (Fig. 13 C) equal. Merus triangular in cross section, dorsal margin rugose, dorsal margin, outer surface setose. Carpus smooth, inner angle absent. Chela with smooth surfaces, palm about 1.2 times longer than dactylus; immovable finger with weakly sinuous cutting edge, cutting edge convex medially, lined with small teeth; movable finger with cutting edge concave on distal half.
Ambulatory legs (P2–P5) (Figs. 13 B, C, 16H, I) relatively short, P3 longest, P5 shortest; upper surface glabrous, setae on margins, lower surfaces of carpus, propodus. Merus as long as or slightly longer than combined length of respective propodus, dactylus, extensor margin unarmed, flexor margin armature of P2–P5 as follows: P2 1+0/1+0, P3 1+0/1+0, P4 1+0/1+0, P5 0+0/1+1. Flexor margin of basis-ischium of P5 unarmed. Dactylus very short, claw-like.
Abdomen (Figs. 14 C, 16G) with all somites, telson distinct, mobile.
Description (male paratype). Carapace (Figs. 13 A, 15A) subquadrate, about 1.3 broader than long; dorsal surface smooth, regions poorly demarcated, shallow depression on each hepatic region. Front (Fig. 15 B) strongly deflexed, medially concave in dorsal view. Orbital margins (Fig. 15 B) entire, oval, no gap between cornea, external orbital angle. Epistome longer than that of female, posterior margin slightly concave. Antennule, antenna as in female. Eyes (Fig. 15 B) short, stout, with distinct cornea.
Third maxillipeds (Figs. 15 C, 16A) covering four-fifths of buccal cavern when closed; similar to female third maxillipeds except for more rounded distomesial angle.
Thoracic sternites 1, 2 fused, sternites 2/3 demarcated by distinct suture, 3/4 demarcated by low ridge, sternites 4–8 demarcated by shallow, narrow sutures, press button of abdominal locking mechanism present on distal quarter of sternite 5; penis emerging from near anterior border of sternite 8.
Chelipeds (Fig. 15 C) relatively strong, slightly unequal in size. Merus triangular in cross section, ventro-outer margin granulated, dorsal margin rugose, dorsal margin, outer surface setose. Carpus smooth, inner angle rounded. Chelae, ambulatory legs (Figs. 13 A, 16C, D) as in female.
Flexor margin armature of P2–P5 as follows: P2 0+2/0+1, P3 1+5/1+3, P4 1+7/1+3, P5 1+1/1+1. Flexor margin of basis-ischium of P5 unarmed. Dactylus very short, claw-like.
Abdomen (Fig. 16 B) with all somites, telson distinct, mobile, relatively narrow, somite 2 broadest, somite 3 to telson forming straight lateral margins. G1 (Fig. 16 E, F) simple, stout, proximal five-sixths straight, distal onesixth bent inwards towards median part of sternum.
Colour. In life, the overall carapace, chelipeds, and legs are dirty white; the dorsal surface of the carapace with several orange spots (Fig. 13). The setae lining the sides of the carapace and legs are light brown, and the cornea was bright yellow (Fig. 13).
Etymology. The name is derived from the presence of orange dots on the dorsal surface of the carapace in life, a distinctive feature of this species.
Remarks. Selwynia punctata n. sp., differs from congeners in having proportionately the stoutest G1 (Fig. 16 E, F), longest ischium of the third maxilliped (1.4 times length of merus) (Fig. 16 A), the possession of only a single tooth on flexor margin of the male P2–P5 merus (Fig. 16 C, D), and presence of dense long setae on the chelipeds and ambulatory legs (Figs. 14 C, 15C).
Biology. The present specimens were collected by yabby-pumps and the hosts are not known.
Distribution. Known only from Moorea, French Polynesia.
description: Published as part of Ng, Peter K. L. & Rahayu, Dwi Listyo, 2016, On the genera Selwynia Borradaile, 1903, and Gandoa Kammerer, 2006, with descriptions of two new species from Papua New Guinea and French Polynesia (Crustacea: Decapoda: Brachyura: Aphanodactylidae), pp. 339-370 in Zootaxa 4092 (3) on pages 358-363, DOI: 10.11646/zootaxa.4092.3.2, http://zenodo.org/record/254902