Rochinia kagoshimensis Lee & Forges 2017, comb. 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
Rochinia
Rochinia kagoshimensis

description: Rochinia kagoshimensis (Rathbun, 1932) comb. nov.
Figs 7C, 10 A–F, 11E–J
Pugettia kagoshimensis Rathbun, 1932: 31 (type locality: Sata Misaki Light, Japan).
Pugettia kagoshimensis – 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, 10A, D). 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). 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). G1 with wide, flattened tip; constricted in distal region near tip (Fig. 11 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).
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 A–C. The overall carapace morphology shows long hepatic spines that are not typically seen in Pugettia Dana, 1851 (Figs 7C, 10A, D). The G1 morphology (Fig. 11) 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), whereas for the SCS specimen, the pseudorostral spines are distinctly curved outwards (Fig. 10D). On the carapace of the specimens, the hepatic and branchial spines of the holotype are pointed in a more upward direction (Fig. 10A, C) while in the SCS specimen, it is pointed more outwards (Fig. 10D, F). The strong and blunt cardiac spine on the carapace is relatively thicker on the SCS specimen (Fig. 10F) compared to the holotype (Fig. 10C). On the pterygostomial region, the holotype of R. kagoshimensis has two small granules on the edge (Fig. 10B) whereas on the SCS specimen, there are three small granules instead (Fig. 10E). 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) to R. debilis Rathbun, 1932 (Fig. 12) 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), while in R. debilis, it is reduced to a small swelling (Fig. 12). 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). 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.
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 19-22, DOI: 10.5852/ejt.2017.358, http://zenodo.org/record/3836444