Fennera chacei Holthuis 1951
Creators: name: Marin, Ivan
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Palaemonidae
Fennera
Fennera chacei

description: Fennera chacei Holthuis, 1951
(Figs. 1–4, 8 d–f)
Fennera chacei Holthuis, 1951: 171, pl. 54 (type locality: Secas Island, Pacific coast of Panama).
Type material. Holotype: ovigerous female (pcl. 3.1 mm, tl. 7.5 mm) (USNM 88888), Pacific coast of Panama, Secas Island, Bay of South Island, Allan Hancock Expedition 252-34, from Porites, 22 February 1934.
Paratypes: 4 ovig. females, 3 males and 3 or 4 damaged specimens (dissected) (USNM 90279), Pacific coast of Panama, Bahia Honda, shallow waters, about 2 fm, coral, 10 March 1933, Allan Hancock Expedition 114-33; 1 ovigerous female and 3 males (USNM 90282), Pacific coast of Colombia, Gorgona Island, from Pocillopora sp., coll. W. Schmitt, 22 January 1935.
Other material examined. 58 females and 34 males (UM 32.9592), Pacific coast of Panama, Uva Island, 07˚49’N, 81˚46W, 3–7 m, “live 26“, coll. G. Hockensmith, March 2005; 1 male (RMNH D 51389), Pacific coast of Colombia, Gorgona Island, on Pocillopora damicornis, coll. H. Prahl, 20 August 1983.
Diagnosis. Small-sized pontoniine shrimp species with subcylindrical body. Carapace swollen, smooth, with armed lower orbital margin (Figs. 1 a–c, 4). Rostrum short, pointing distally, compressed, turned forward; dorsal rostral carina well developed extending onto carapace, with 3–5 small dorsal teeth, with 1 or 2 teeth situated posterior to level of orbit (Fig. 2 c); ventral rostral carina and proximal lateral rostral lamina feebly developed (Fig. 2 a, c). Orbit well developed, deep, lower orbital margin armed with several, usually 3 or 4, sharp turned forward small teeth; inferior orbital angle bluntly produced forward. Abdominal somites smooth; pleura of abdominal somites I– V rounded (Fig. 1). Telson (Fig. 2 d) about 2.5 times as long as proximal width, narrowing distally, with 2 pairs of small dorsal submarginal spines at 0.25 and 0.65 of telson length; distal margin of telson armed with 3 pairs of spines, with intermediate spines large, hook-shaped (Fig. 2 e). Eyes well developed, large, with swollen eyestalk and with ovate cornea (Fig. 2 a). Antennula (Fig. 2 f) well developed; basal segment about twice longer than wide, with distolateral angle bearing large acute tooth, without medial convex projection (lobe); without ventral tooth. Antenna (Fig. 2 g) well developed, basicerite large, about twice as long as wide, without distolateral tooth; scaphocerite wide, about 1.5 times longer than maximal width, with well developed acute distolateral tooth not reaching to level of distal margin of blade. Pereiopod I with relatively stout segments; carpus about 3.5 times as long as wide, equal to length of chela and slightly shorter than merus; propodus (palm) about 3 times longer than wide, about 2.5 times longer than fingers, slightly tapering distally; fingers slender, with straight, smooth cutting margins. Pereiopods II dissimilar in shape and unequal size (Figs. 1, 3 a, g, 8d, e); major pereiopod II (Figs. 3 a–d, 8e) with relatively robust and smooth segments; carpus triangular, flaring distally, overlapping carpo-propodal articulation, with smooth distal margin (Fig. 3 b–d); palm cylindrical, about 2.5 times as long as wide, slightly swollen in medial part, expanded ventrally in its distoventral part; fingers robust, about 1/3 of the length of palm; fixed finger (pollex) slender, pointed distally, about twice longer than wide, with smooth entire cutting margin and simple sharp curved tip; movable finger (dactylus) relatively stout, flattened, with feebly developed dorsal carina, with entire smooth cutting margin and simple curved tip (Fig. 3 e, f); minor pereiopod II (Figs. 3 g, 8d) with relatively slender proximal segments; carpus about 2.5 times longer than wide, equal to length of merus, shorter than propodus, smooth, unarmed; propodus slightly flattened, about 3 times as long as wide, with straight and smooth lateral margins, distodorsal margin with rounded depression covered with numerous minute teeth and simple setae; pollex well developed, flattened, bluntly rounded distally (Fig. 3 k); dactylus well developed, robust, flattened, about as long as wide, bluntly rounded distally, with dorsal margin covered with minute teeth and simple setae (Fig. 3 h, i). Pereiopod III (Fig. 8 f) with smooth unarmed segments (Fig. 2 j); carpus about 2.5 times longer than wide, about half of length of propodus and slightly shorter than merus; propodus slender, pointed distally, about 5.5 times as long as proximal its width, with smooth unarmed margins; dactylus simple, with proximal rounded ventral protuberance and simple slender and curved unguis. Pereiopods III–V similar.
Uropods slender, slightly exceeding telson; distolateral margin of uropodal exopod rectangular with well developed slender distolateral spine (Fig. 2 j).
Males are morphologically similar to female, but smaller in size. No significant sexual dimorphism in pereiopod II was observed (Fig. 1).
Remarks. The described specimens agree well with the original description of Fennera chacei given by Holthuis (1951). For morphological differences from the second species of the genus, see below.
Distribution. This work confirms the presence of the species along the Pacific coasts of Panama and Columbia. Previously published records of Fennera chacei from the Indo-West Pacific including Kenya, Seychelles Islands, Réunion, Maldive Islands, Sri Lanka, Japan, Papua New Guinea, Queensland, Marshall Islands, Hawaiian Islands, Clipperton Island and Galapagos Islands) need to be verified because they could belong to the newly described species.
description: Published as part of Marin, Ivan, 2011, Fennera holthuisi sp. nov., a new coral-associated pontoniine shrimp (Decapoda: Palaemonidae: Pontoniinae) from Moorea, French Polynesia, pp. 29-39 in Zootaxa 2890 on pages 29-33, DOI: 10.5281/zenodo.201482