Pleisticanthoides piccardorum Ng & Forges, 2012, n. sp.
Creators: name: Ng, Peter K. L.
name: Forges, Bertrand Richer De
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Inachidae
Pleisticanthoides
Pleisticanthoides piccardorum

description: Pleisticanthoides piccardorum n. sp.
(Figs. 1 D, 7, 8B, 9C, 10B, 11E–G)
Material examined. Holotype: Ovigerous female (18.6 × 13.6 mm) (MNHN-IU-2012-768), Big Bay, Espiritu Santo I., Vanuatu, station AT 92, 14°59.7'S 166°51.9'E, 722–780 m, coll. SANTO 2006, 13 October 2006.
Paratypes: 1 male (13.1 × 9.9 mm) (with rhizocephalan), 1 damaged male (17.4 × 12.9 mm) (MNHN-IU-2012- 769), Big Bay, Espiritu Santo I., Vanuatu, station AT 89, 14°59.7'S 166°55.3'E, 630–658 m, coll. SANTO 2006, 13 October 2006.— 1 male (20.7 × 16.8 mm) (ZRC 2012.0909), Big Bay, Espiritu Santo I., Vanuatu, station AT 98, 15°06.6'S 166°50.8'E, 347–394 m, coll. SANTO 2006, 14 October 2006. Additional material: 1 female (16.0 × 22.4 mm) (MNHN-IU-2011-1175), south of Lae, Gulf of Huon, Papua New Guinea, station CP 3630, 06°54’S 147°03’E, 305–307 m, coll. BIOPAPUA 2010, 22 August 2010.—1 ovigerous female (15.7 × 22.7 mm) (MNHN- IU-2011-1895), point southwest of Manus I., Papua New Guinea, station CP 3693, 02°10’S 147°17’E, 300 m, coll. BIOPAPUA 2010, 29 September 2010.
Description. Carapace pyriform; dorsal surface covered by numerous hooked setae, otherwise smooth, without spines, spinules or granules; carapace regions well-defined. Pseudorostral spines short, distinctly diverging; base with strong sharp tooth directed ventrally. Ocular peduncle long, slender; cornea small, round, slightly wider than diameter of peduncle; small blunt spine on upper surface of peduncle. Interantennular spine (= true rostrum) distally bifid. Basal antennal article with 3 blunt spines, one medially on outer margin, 2 distal; urinary article with strong triangular tooth adjacent to prominent green gland. Supraocular eave with 2 short triangular teeth: strong supraocular spine plus longer, curved subhepatic spine; small spine about half length of supraocular spine between subhepatic, supraocular spines. Third maxilliped with segments flattened, covered by long setae; outer border of carpus crenulated. Ambulatory legs long, slender, lined with long, stiff setae. Chelae not inflated, with longer setae on inner side of carpus. Second pereiopod longest; segments with setae arranged in 2 rows along margins. Abdomen with 6 free somites plus telson; sixth somite with distolateral margins expanded, overlapping telson. G1 curved, distinctly C-shaped, distal third dorsolaterally flattened but slightly twisted.
Etymology. The name honors the Piccard family, Auguste Piccard (1884–1962), the inventor of the bathyscaphe, and his son, Jacques Ernest-Jean Piccard (1922–2008), who, together with U.S. Navy officer Don Walsh, were the first men to dive to a record depth of 10,915 m in the Mariana Trench in the Trieste on January 23 1960.
Remarks. Pleisticanthoides piccardorum n. sp. is easily distinguished from P. c a m e ro n i n. sp. by several notable characters. The supraocular tooth of in P. cameroni n. sp. is proportionately larger and stronger (Figs. 1 C, 8A versus Figs. 1 D, 8B) and the basal antennal article relatively longer and more slender with smaller spines (Fig. 9A) than in P. piccardorum n. sp. which has the article stouter with three spines (two distal and one on the outer margin) (Fig. 9B). The secondary spine at the base of the pseudorostral spine is directed outwards in P. cameroni n. sp. (Fig. 1 C) but in P. piccardorum n. sp., it is distinctly directed ventrally (Fig. 1 D). The G1 of P. piccardorum n. sp. (Fig. 11 E) is also more strongly bent than that of P. cameroni n. sp. (Fig. 11 C). In addition, the setae on the pereiopods of P. piccardorum n. sp. are relatively shorter and less stiff (Fig. 8 B) compared to those of P. c a m e ro n i n. sp., which are longer, stiff and spine-like (Fig. 8 A).
The base of the longest setae along the ventral margin of the pereiopod meri (especially the second leg) is heavily chitinised and resembles a sharp tubercle. This sharply contrasts with the almost transparent setae. As such, the ventral margin of the merus appears to be lined with a row of short sharp spines (Fig. 7 B), which is actually not the case.
One male specimen (MNHN-IU-2012-769) was parasitized by a rhizocephalan and as a result had a reduced G1 and a feminised abdomen.
description: Published as part of Ng, Peter K. L. & Forges, Bertrand Richer De, 2012, Pleisticanthoides Yokoya, 1933, a valid genus of deep-sea inachid spider crabs (Crustacea: Decapoda: Brachyura: Majoidea), with descriptions of two new species from the Philippines, Papua New Guinea and Vanuatu, pp. 65-81 in Zootaxa 3551 on pages 75-80, DOI: 10.5281/zenodo.208425