Rochinia kagoshimensis ( Rathbun, 1932 ) Lee & Forges, 2017

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), European Journal of Taxonomy 358, pp. 1-37 : 19-22

publication ID	https://doi.org/ 10.5852/ejt.2017.358
DOI	https://doi.org/10.5281/zenodo.3852108
persistent identifier	https://treatment.plazi.org/id/A3559C5D-FF92-FFE4-FE1B-EECEFAF3F9C6
treatment provided by	Carolina
scientific name	Rochinia kagoshimensis ( Rathbun, 1932 )
status	comb. nov.

Treatment

Rochinia kagoshimensis ( Rathbun, 1932) comb. nov.

Figs 7C View Fig , 10 View Fig A–F, 11E–J

Pugettia kagoshimensis Rathbun, 1932: 31 View in CoL (type locality: Sata Misaki Light, Japan).

Pugettia kagoshimensis View in CoL – Yokoya 1933: 153. — Sakai 1938: 253 (key), 259 –260; 1976: 194 (key), 198 –199, text-fig. 105. — Griffin & Tranter 1986a: 92 (key). — Wicksten & Stachowicz 2013: 359 (list). — Ohtsuchi et al. 2014: 557 (list).

Material examined

JAPAN: holotype, ♂ (11.2 × 6.8 mm) ( USNM 48253 ), stn 4935, eastern sea, off Kagoshima gulf, coll. Albatross , 16 Aug. 1906.

SOUTH CHINA SEA: 1 ♂ (10.7 × 6.9 mm) ( ZRC 2016.0549), Dongsha, northwest of Dongsha, stn CP4159, 20°45.92′ N, 116°41.11′ E to 20°47.62′ N, 116°42.35′ E, 221– 190 m, coll. ZHONGSHA 2015 Expedition, 30 Jul. 2015.

Comparative material

JAPAN: holotype of Rochinia debilis Rathbun, 1932 , ♀ (10.8 × 7.0 mm) ( USNM 49572), stn 5091, Joga Shima Light, 35°04.10′ N, 139°38.12′ E, 360 m, coll. Albatross, 26 Oct. 1906; 1 ♂ (23.1 × 15.8 mm), 1 ♀ (21.6 × 14.7 mm) ( SMF 49904), Tsurugasaki, Miura City, Kanagawa Prefecture, coll. K. Sakai, 8 Mar. 1998; 2 ♂♂ (28.9 × 21.0 mm, 27.1 × 19.8 mm), 1 ovigerous ♀ (27.4 × 18.0 mm) ( SMF 49905), Tsurugasaki, Miura city, Kanagawa Prefecture, coll. K. Sakai, 19 Jun. 1998.

Description

Small species. Carapace triangular, covered with tomentum, large tuft of long setae on mesogastric region ( Figs 7C View Fig , 10A, D View Fig ). Pseudorostral spines relatively long, curved, diverging. Small round eyes. Supraorbital eave narrow, forming sharp distal angle. Small postorbital angle forming cavity protecting eye. Carapace with distinct spines: 2 long hepatic spines, pointed obliquely outwards; 1 short gastric spine surrounded by hooked setae; 1 strong thick cardiac spine with blunt squarish tip; 2 thick branchial spines long, pointing outward with blunt tips, proximal small spine on each branchial spine and pointing upwards; 1 tooth on posterior margin of carapace, with spine on anterior region of tooth. Long setae along lateral edge of carapace, between hepatic and branchial spines.

Antennae shorter than pseudorostral spine. Antennules totally retractable inside deep fossae. Basal antennal article wide, fused on carapace, rectangular with straight distal edge, sharp external distal angle ( Fig. 10B, E View Fig ). Distinct tubercle at base of basal antennal article. Epistome small. Pterygostomial region with 2 or 3 small granules on edge. Buccal frame squarish.

Male cheliped short, propodus slightly inflated, fingers serrulate, carpus carinate, merus bearing swellings on border, covered by short setae. Ambulatory legs: P2 longest; on each leg, distal border of carpus and merus with stout setae; merus with several small bulbous setae; distal end of merus with

blunt spine; dactylus slightly curved with sharp tip, proximal region covered with row of setae, short spines on distal third of dactylus.

Male thoracic sternum anteriorly slightly depressed. Male abdomen with triangular telson and 6 somites, widest at second and third ( Fig. 10B, E View Fig ). G1 with wide, flattened tip; constricted in distal region near tip ( Fig. 11 View Fig E–J).

Colouration

In the fresh SCS specimen of R. kagoshimensis , the carapace is white, with the pseudorostral spines orange-pink, and the ambulatory legs orange with the dactylus and distal part of propodus white ( Fig. 7C View Fig ).

Remarks

Little is known of this species. The species was originally described as Pugettia kagoshimensis by Rathbun (1932) from Japan, with no figures illustrated. Sakai (1976) provided a rather schematic line drawing of the holotype specimen ( Sakai 1976: text-fig. 105). The holotype is shown in Fig. 10 View Fig A–C. The overall carapace morphology shows long hepatic spines that are not typically seen in Pugettia Dana, 1851 ( Figs 7C View Fig , 10A, D View Fig ). The G1 morphology ( Fig. 11 View Fig ) is also unlike typical Pugettia , which is scyriform shape with three angles at the G1 tip. This species is therefore transferred to Rochinia sensu lato on the basis of the G1 morphology. This species was previously known only from Japan from the holotype specimen.

The specimen collected from the SCS is very similar to the type of R. kagoshimensis ( Rathbun, 1932) comb. nov., although there are some differences. For the holotype of R. kagoshimensis , the pseudorostral spines are straight and diverging ( Fig. 10A View Fig ), whereas for the SCS specimen, the pseudorostral spines are distinctly curved outwards ( Fig. 10D View Fig ). On the carapace of the specimens, the hepatic and branchial spines of the holotype are pointed in a more upward direction ( Fig. 10A, C View Fig ) while in the SCS specimen, it is pointed more outwards ( Fig. 10D, F View Fig ). The strong and blunt cardiac spine on the carapace is relatively thicker on the SCS specimen ( Fig. 10F View Fig ) compared to the holotype ( Fig. 10C View Fig ). On the pterygostomial region, the holotype of R. kagoshimensis has two small granules on the edge ( Fig. 10B View Fig ) whereas on the SCS specimen, there are three small granules instead ( Fig. 10E View Fig ). As there is only one male specimen collected from SCS, it is uncertain if both are conspecific or these differences are only the result of variation. Both specimens are treated as the same species for the time being.

Rochinia kagoshimensis has a similar general carapace shape ( Fig. 10A, E View Fig ) to R. debilis Rathbun, 1932 ( Fig. 12 View Fig ) due to both having similar pseudorostral spines, large and diverge branchial spines; and dorsal surface of the carapace is covered by a tomentum of short setae. The main differences are on the cardiac spine: wide and blunt in R. kagoshimensis ( Fig. 10C, F View Fig ), while in R. debilis , it is reduced to a small swelling ( Fig. 12 View Fig ). In R. kagoshimensis , the hepatic spines are proportionately longer compared to R. debilis , which is reduced to a short spine on a convexity ( Fig. 8A View Fig ). Rochinia debilis is currently known only from Japan ( Sakai 1976).

Distribution

This species was recorded from Japan ( Rathbun 1932). This is a new record for the South China Sea.

ZRC	Zoological Reference Collection, National University of Singapore
USNM	Smithsonian Institution, National Museum of Natural History
SMF	Forschungsinstitut und Natur-Museum Senckenberg

Copyright notice

No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.

Taxonomy

Kingdom	Animalia
Phylum	Arthropoda
Class	Malacostraca
Order	Decapoda
Family	Epialtidae
Genus	Rochinia