Siderochinia kagoshimensis ( Rathbun, 1932 ) Yan & Lee & Forges & Ng, 2021

Yan, Bee, Lee, Forges, Bertrand Richer De & Ng, Peter K. L., 2021, The generic affinities of the Indo-West Pacific species assigned to Rochinia A. Milne-Edwards, 1875 (Crustacea: Brachyura: Majoidea: Epialtidae), Raffles Bulletin of Zoology 69, pp. 19-44 : 34-36

Siderochinia kagoshimensis ( Rathbun, 1932) , new combination

( Figs. 7A–C , 8A–C , 9G–J )

Pugettia kagoshimensis Rathbun, 1932: 31 (type locality: Sata Misaki Light, Japan). – Yokoya, 1933: 153. – Sakai, 1938: 253 (key), 259, 260. – Sakai, 1976: 194 (key), 198, 199, textfig. 105. – Griffin & Tranter, 1986a: 92 (key). – Wicksten & Stachowicz, 2013: 359 (list). – Ohtsuchi et al., 2014: 557 (list).

Rochinia kagoshimensis – Lee et al., 2017: 19, 22, figs. 7C, 10A–C, 11E, F [new combination]. – Ng et al., 2017b: 53 (list). – Tavares & Santana, 2018: 223 (list).

Pugettia kagoshimaensis [sic] – Ng et al., 2017a: 135 (list).

Material examined. Holotype: male (11.2 × 6.8 mm) (USNM 48253), stn 4935, off Kagoshima Gulf , Eastern Sea, Japan, coll. ALBATROSS, 16 August 1906.

Description. Carapace triangular, covered with tomentum, large tuft of long setae on mesogastric region ( Fig. 7A ). Pseudorostral spines relatively long, curved, diverging. Supraorbital eave narrow, with sharp preorbital 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 truncate tip; 2 thick branchial spines long, pointing outward with rounded tips, proximal small spine on each branchial spine, pointing upwards; 1 tooth on posterior margin of carapace, with spine on anterior region of tooth ( Figs. 7A , 8A, B ); long setae along lateral margin of carapace, between hepatic and branchial spines.

Antennal flagellum shorter than pseudorostral spine. Basal antennal article longer than broad, sharp distal angle, with straight outer margin. Buccal frame squarish. Pterygostomial region with 2 or 3 small granules on outer margin ( Fig. 7B ).

Male cheliped short, propodus slightly inflated, fingers serrulate, carpus carinate, merus with granules on border, covered by short setae. Ambulatory legs slender; 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, 4 short spines on inner margin of distal third of dactylus of P5, weaker spines on inner margin of dactylus of P2–P4 ( Figs. 7A , 8C ).

Male thoracic sternum anteriorly slightly depressed; sternites 3, 4 narrow with lateral margin slightly constricted medially. Male pleon triangular with triangular telson, widest at second and third somites ( Fig. 7B ). G1 straight with wide, flattened tip; constricted in distal region near tip ( Fig. 9G, H ).

Remarks. The species was originally described as Pugettia kagoshimensis by Rathbun (1932) without figures. Sakai (1976: text-fig. 105) provided a rather schematic line drawing of the holotype specimen, but later Lee et al. (2017: fig. 10A–C) produced more detailed figures. The overall carapace morphology has long hepatic spines that are not typically seen in Pugettia ( Lee et al., 2017: figs. 7C, 10A, D; Fig. 7A ). The G1 morphology as shown by Lee et al. (2017: fig. 11E–J) ( Fig. 9G, H ) is also unlike typical Pugettia , which is scyriform with three angles at the G1 tip ( Fig. 9E, F ). This species was therefore assigned to Rochinia on the basis of the G1 morphology by Lee et al. (2017).

Distribution. Siderochinia kagoshimensis , new combination, is only known from Japan ( Rathbun, 1932).

Figures

Fig. 7. A–C, Siderochinia kagoshimensis (Rathbun, 1932) new combination, holotype male (11.2 × 6.8 mm) (USNM 48253), Japan; D–F, S. aglaos, new species, holotype male (10.7 × 6.9 mm) (ZRC 2016.0549), South China Sea (after Lee et al., 2017: fig. 10D–F). A, D, overall dorsal view; B, E, overall ventral view; C, F, lateral view of carapace.

Fig. 8. A–C, Siderochinia kagoshimensis (Rathbun, 1932) new combination, holotype male (11.2 × 6.8 mm) (USNM 48253), Japan; D–F, S. aglaos, new species, holotype male (10.7 × 6.9 mm) (ZRC 2016.0549), South China Sea. A, D, side view of cardiac spine; B, E, dorsal view of intestinal spine along lateral carapace margin; C, F, dorsal view of P5.

Fig. 9. Left G1 and G2. A, B, Laubierinia globulifera (Wood-Mason, in Wood-Mason & Alcock, 1891) new combination, male (9.2 × 6.0 mm) (AM P.34652), Indonesia; C, D, Oxypleurodon fultoni (Grant, 1905) new combination, holotype male (8.2 × 5.1 mm) (AM G.5427), Australia; E, F, Pugettia vesicularis (Rathbun, 1907) new combination, holotype male (14.6 × 10.6 mm) (USNM32860), Galapagos; G–J, Siderochinia kagoshimensis (Rathbun, 1932) new combination, holotype male (11.2 × 6.8 mm) (USNM 48253), Japan (after Lee et al., 2017: fig. 11E, F); K, L, S. aglaos, new species, holotype male (10.7 × 6.9 mm) (ZRC 2016.0549), South China Sea (after Lee et al., 2017: fig. 11G–J). A, C, E, G, K, ventral view; B, D, F, H, L, dorsal view; I, ventral view of G2; J, dorsal view of G2. Scale bar = 1 mm.