Oxypleurodon leonis Lee & Forges 2017, sp. nov.
Creators: name: Lee, Bee Yan
name: Forges, Bertrand Richer De
name: Ng, Peter K. L.
Publisher: name: Zenodo
Year: 2017
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Epialtidae
Oxypleurodon
Oxypleurodon leonis

description: Oxypleurodon leonis sp. nov.
urn:lsid:zoobank.org:act: AB7D2D15-4E55-4F8C-AD73-76157AD6ECF3
Figs 4B, 5 A–C, 6A–D
Diagnosis
Small species, carapace pyriform, bearing plates and obtuse spines, covered by continuous short tomentum. Short diverging pseudorostral spines, long setae on inner border. Postocular plate small, flattened, forming cavity protecting eye. Hepatic plate elongate dorso-ventrally, with concave surface. Carapace border with long, narrow sub-branchial plate. Dorsal carapace bearing several swellings with blunt spines covered by short round setae: 1 mediogastric, 2 epigastrics, 1 prominent cardiac swelling rounded on top, 2 sharp, curved branchial plates, 2 epibranchial swellings, 1 prominent posterior blunt tooth. Basal antennal article fused to carapace, curved, with smooth flattened surface. Male cheliped inflated, smooth surface, propodus enlarged, borders carinate; carpus short, with 2 carinae; merus trigonal in cross-section, carinate; ventral side of merus with 2 granules; distal part of basis-ischium forming blunt tooth along merus.
Etymology
The species name is dedicated to our colleague and friend Professor Leo Tan, who is actively encouraging a multitude of biodiversity studies in Singapore. The name is used as a noun in apposition.
Material examined
Holotype
SOUTH CHINA SEA: ♂ (13.5 × 9.0 mm), north of Zhongsha, stn DW4145, 16°06.69′ N, 114°20.26′ E to 16°07.50′ N, 114°18.98′ E, 180–226 m, coll. ZHONGSHA 2015 Expedition, 26 Jul. 2015 (NTOU).
Paratypes
SOUTH CHINA SEA: 1 ♂ (15.1 × 9.6 mm) [photographed] (ZRC 2016.0541), 3 ♂♂ (15.6 × 10.5 mm, 11.7 × 7.2 mm), 1 ♂ with Sacculina (13.5 × 8.5 mm), 1 ♀ (11.3 × 7.0 mm), 2 ovigerous ♀♀ (11.3 × 7.5 mm, 10.9 × 7.2 mm) (ZRC 2016.0542), 1 ♂ (14.8 × 10.0 mm), 1 ovigerous ♀ (11.2 × 7.1 mm) (NTOU), same locality and collection data as holotype; 1 ♂ (14.2 × 8.9 mm) [photographed] (ZRC 2016.0543), north of Zhongsha, stn CP4153, 16°13.94′ N, 114°27.21′ E to 16°14.247′ N, 114°29.55′ E, 318 m, coll. ZHONGSHA 2015 Expedition, 27 Jul. 2015; 2 ♂♂ (13.6 × 9.0 mm, 11.5 × 7.2 mm), 1 ovigerous ♀ (11.6 × 7.2 mm) (MNHN-IU-2016-178), north of Zhongsha, stn CP4147, 16°09.83′ N, 114°15.25′ E to 16°08.15′ N, 114°17.97′ E, 343– 259 m, coll. ZHONGSHA 2015 Expedition, 26 Jul. 2015.
Comparative material
PHILIPPINES: Oxypleurodon bipartitum (Guinot & Richer de Forges, 1986): 1 ♀ (10.4 × 6.6 mm), 1 ovigerous ♀ (10.4 × 6.2 mm) (ZRC 2012.1163), stn CP2340, off Balicasag Island, off Aliguay Island, Bohol Sea, 9°29.4′ N, 123°44.4′ E, 271–318 m, coll. Panglao 2005 Expedition, 23 May 2005; 2 ♂♂ (13.1 × 8.5 mm, 8.4 × 5.6 mm) (ZRC 2016.0082), stn PN1, Balicasag Island, off Panglao Island, Bohol Sea, tangle nets, coll. Dec. 2003; 3 ♂♂ (only the measurement of the largest specimen is given: 13.8 × 8.5 mm), 1 ♀ (10.0 × 6.6 mm), 1 ovigerous ♀ (10.8 × 6.8 mm) (ZRC 2001.0612), Balicasag Island, off Panglao Island, Bohol Sea, 50–500 m, tangle nets, coll. local fishermen, 28 Nov. 2001.
Description
Small species, pyriform carapace with plates, obtuse spines, covered by layer of short tomentum (Figs 4B, 5A). Short diverging pseudorostral spines, long setae on inner border. Supraocular eave narrow, forming sharp anterior angle (Figs 4B, 5A). Postocular plate small, flattened, forming a cup protecting eye. Hepatic plate elongate dorso-ventrally, with concave surface (Figs 4B, 5A). Carapace border with long, narrow sub-branchial plate (Figs 4B, 5A). Dorsal carapace bearing several swellings with blunt spines covered by short round setae: 1 mesogastric, 2 epigastrics, 1 prominent cardiac swelling rounded on top, 2 sharp, curved branchial plates, 2 epibranchial swellings, 1 prominent posterior blunt tooth (Figs 4B, 5A).
Antennae at same level of pseudorostral spines. Antennules completely retractable in deep fossae. Basal antennal article fused to carapace, slightly curved, with smooth flattened surface, slightly rounded external distal angle; distinct tubercle at base of basal antennal article (Fig. 5B). Squarish epistome. Pterygostomial region enlarged into plate with rounded edge (Fig. 5B). Buccal frame totally covered by third maxillipeds when closed.
Male cheliped inflated, smooth surface, propodus enlarged, each border carinate, cutting edges of fingers serrulate; carpus short with 2 carinae; merus trigonal in cross-section, carinate; ventral side of merus with 2 granules; distal part of basis-ischium forming blunt tooth. Ambulatory legs relatively short, P2 longest; merus, carpus, and propodus with strong stout setae; dactylus strong, claw-like, with sharp, curved tip.
Male thoracic sternum anteriorly depressed, sternites 1–3 fused (Fig. 5B). Male abdomen with triangular telson and 6 free somites (Fig. 5B). G1 straight with flattened tip (Fig. 6).
Colouration
In the fresh specimens of O. leonis sp. nov., the carapace is slightly pink and covered by a layer of white tomentum; chelipeds bright white, ambulatory legs pinkish (Fig. 4B).
Remarks
The material from the ZHONGSHA cruise is superficially close to O. bipartitum (Fig. 4A), which was originally described from material collected off the western coast of Luzon, the Philippines. Oxypleurodon bipartitum s. str. was collected in large numbers by fishermen using tangle nets in Balicasag Island, central Philippines (Richer de Forges & Ng 2009b), which makes it possible for us to directly compare the two species. In typical O. bipartitum (Fig. 4A), the pseudorostrum is proportionately longer and the carapace not as wide as the SCS material. In O. leonis sp. nov., the supraocular eave is narrow and forms a thin “overhang” (Figs 4B, 5A) as compared to O. bipartitum in which the same structure is thick (Fig. 4A). The shape of the branchial plate is also different, being distinctly more flattened in O. bipartitum rather than more convex and slightly curved in O. leonis sp. nov. (Figs 4B, 5A). In O. bipartitum, the lateral plates (postocular, hepatic, and lateral branchial) are relatively larger and more foliose (Fig. 4A) compared to those in O. leonis sp. nov. (Figs 4B, 5A). The pattern of setal arrangement on both species is very different as well; in O. leonis sp. nov., there is a distinct, even tomentum of short setae on the cardiac, gastric, and epibranchial regions (Figs 4B, 5A) whereas in O. bipartitum, the same regions have groups of long and stout setae instead. In O. leonis sp. nov., the posterior border of the carapace is slightly carinate (Figs 4B, 5A) while in O. bipartitum, it forms a large curved carina (Fig. 4A).
Distribution
Only known from South China Sea.
description: Published as part of Lee, Bee Yan, Forges, Bertrand Richer De & Ng, Peter K. L., 2017, Deep-sea spider crabs of the families Epialtidae MacLeay, 1838 and Inachidae MacLeay, 1838, from the South China Sea, with descriptions of two new species (Decapoda, Brachyura, Majoidea), pp. 1-37 in European Journal of Taxonomy 358 on pages 10-13, DOI: 10.5852/ejt.2017.358, http://zenodo.org/record/3836444