Sargassocarcinus sublimis ( Rathbun, 1916 )

Ng, Peter K. L., Lin, Chia-Wei & Naruse, Tohru, 2016, Revision of the spider crab genus Sargassocarcinus Ward, 1936 (Crustacea: Brachyura: Epialtidae), Zootaxa 4162 (2), pp. 313-330 : 320

Sargassocarcinus sublimis ( Rathbun, 1916)

( Figs 2 D; 3D; 5A–E, H; 6A–H; 7G, I; 8B; 9F–I)

Peltinia sublimis Rathbun, 1916: 536 .

Sargassocarcinus sublimis Sakai 1965 , text-fig. 11c: 75; Serène 1968: 53; Griffin 1976: 211; Griffin & Tranter 1986: 97 (part); Ng et al. 2008: 101 (part).

Material examined. Holotype: male (13.3 × 10.8 mm) ( USNM 48247 ), station 5136, vicinity of Jolo Island, 9 fathoms (= 16.4 m) , Philippines, coll. R.V. Albatross, 9 February 1908 .

Diagnosis. Carapace with relatively lower median tubercles on protogastric region; sub-branchial regions not raised ( Figs 2 D; 3D; 5E); pararostral teeth more deflexed, visible from dorsal view as short structure ( Figs 3 D; 7I); postorbital lobe not discernible, confluent with lateral expansion ( Fig. 3 D); eye relatively long ( Fig. 5D ); wing-like lateral expansion relatively thicker, with relatively deep asymmetrical concavity separating 2 unequal lateral lobes, anterior lobe much larger, posterior margin of posterior lobe meeting posterolateral margin of carapace as short ridge; ambulatory legs (notably merus) relatively shorter ( Fig. 6 A–H); G1 proportionately longer, more slender, with bent distal part longer, relatively slender, curving downwards ( Fig. 9 F–H).

Colour. Unknown.

Remarks. Rathbun (1916) briefly described Peltinia sublimis from one male from the Philippines, and she differentiated it from allied species mainly by its prominently expanded lateral part of the carapace. Although she observed that the eyes were dorsoventrally flattened and immobile ( Rathbun 1916: 536), she did not elaborate on this unusual feature. She did not provide any figures and this has made its identity uncertain until Sakai (1965: 76, text-fig. 11c) published a schematic figure of the USNM type and argued that it was a distinct species but belonging to Sargassocarcinus Ward, 1936 , instead. Peltinia Dana, 1851 (type species Peltinia scutiformis Dana, 1851 ) is now regarded as a junior subjective synonym of Acanthonyx Latreille, 1828 (see Manning & Holthuis 1981). Sakai’s (1965: text-fig. 11c) figure, however, is inaccurate and does not reflect the actual appearance of the species ( Figs 2 D; 3D).

Griffin & Tranter (1986: 97) synonymised Peltinia sublimis Rathbun, 1916 , with Mimulus cristatus Balss, 1924 , and Sargassocarcinus foliatus Ward, 1936 , being the oldest name, arguing that he could see no major differences between them. His figure of the G1 ( Griffin & Tranter 1986: fig. 18e, f) is of the Japanese specimen and is here referred to S. cristatus ; although this gonopod is not normal in form (see later).

Distribution. Known only from the type locality, vicinity of Jolo Island, Philippines.

Figures

FIGURE 2. Overall habitus. A, Sargassocarcinus foliatus, holotype female (7.8 × 6.8 mm) (QM W 739), Queensland, Australia; B, S. foliatus, male (6.4 × 6.0 mm) (QM W 14482), Queensland, Australia; C, S. foliatus, male (5.7 × 5.4 mm) (QM W 14482), Queensland, Australia; D, S. sublimis, holotype male (13.3 × 10.8 mm) (USNM 48247), Philippines; E, S. cristatus, male (14.4 × 11.7 mm) (ZRC 2015.288), Taiwan; F, S. cristatus, male (12.5 × 10.1 mm) (NMMBCD 4065), Taiwan.

FIGURE 3. Dorsal view of carapace. A, Sargassocarcinus foliatus, holotype female (7.8 × 6.8 mm) (QM W 739), Queensland, Australia; B, S. foliatus, male (6.4 × 6.0 mm) (QM W 14482), Queensland, Australia; C, S. foliatus, male (5.7 × 5.4 mm) (QM W 14482), Queensland, Australia; D, S. sublimis, holotype male (13.3 × 10.8 mm) (USNM 48247), Philippines; E, S. cristatus, male (8.2 × 7.4 mm) (USNM 48248), Japan; F, S. cristatus, male (14.4 × 11.7 mm) (ZRC 2015.288), Taiwan.

FIGURE 6. Ambulatory legs and cheliped. A – H, Sargassocarcinus sublimis, holotype male (13.3 × 10.8 mm) (USNM 48247), Philippines [all same scale]; I – N, S. cristatus, male (8.2 × 7.4 mm) (USNM 48248), Japan [all same scale]. A, left first ambulatory leg; B, right first ambulatory leg (denuded); C, J, left second ambulatory leg; D, right second ambulatory leg; E, K, left third ambulatory leg; F, L, right third ambulatory leg; G, left fourth ambulatory leg; H, M, right fourth ambulatory leg; I, right first ambulatory leg; N, left cheliped. Scales = 1.0 mm.

FIGURE 9. Gonopods. A – E, Sargassocarcinus foliatus, male (6.4 × 6.0 mm) (QM W 14482), Queensland, Australia; F – I, S. sublimis, holotype male (13.3 × 10.8 mm) (USNM 48247), Philippines; J – N, S. cristatus, male (8.2 × 7.4 mm) (USNM 48248), Japan; O – R, S. cristatus, male (14.4 × 11.7 mm) (ZRC 2015.288), Taiwan. A, F, J, O, left G 1 (ventral view); B, G, K, P, left G 1 (dorsal view); C, H, L, Q, distal view of left G 1 (ventral view); D, distal part of left G 1 (dorsal view); E, I, N, R, left G 2; M, distal half of right G 1 (ventral view). Scales: A, B, F, G, I, J, K, M, N, O, P, R = 0.5 mm; C – E, H, L, Q = 0.1 mm.

FIGURE 5. A – E, H, Sargassocarcinus sublimis, holotype male (13.3 × 10.8 mm) (USNM 48247), Philippines; F, S. cristatus, male (14.4 × 11.7 mm) (ZRC 2015.288), Taiwan; G, S. cristatus, male (8.2 × 7.4 mm) (USNM 48248), Japan. A, anterior male thoracic sternum and abdomen; B, male thoracic sternum and abdomen; C, left cheliped; D, orbits, antennules, antennae and epistome; E, F, frontal views of cephalothorax; H, posterior view of cephalothorax. Scales = 1.0 mm.