Lupocycloporus innominatus ( Rathbun, 1909 )

Arzivian, Arteen, Alrubaie, Ahmad, Yang, Jessica, Lin, Huiyu, Zhang, Eva & Leong, Rupert, 2022, Crabs (Crustacea, Decapoda) from the Seas of East and Southeast Asia Collected by the RV Hakuhō Maru (KH- 72 - 1 Cruise) 4. South China Sea, Bulletin of the National Museum of Nature and Science. Series A, Zoology 48 (4), pp. 147-191 : 168

Lupocycloporus innominatus ( Rathbun, 1909)

( Fig. 9A–B )

Material examined. RV Hakuhō Maru KH-72-1 cruise, sta. 45, 1 Ə (CB 15.1 mm including lateral teeth, CL 10.5 mm including frontal teeth), NSMT-Cr 30923.

Remarks. All the chelipeds and ambulatory legs of the male are missing, but the specimen is identifiable as either Lupocycloporus innominatus ( Rathbun, 1909) or L. minutus ( Shen, 1937) , which are often considered as synonymous with, or specifically distinct from, each other. Stephenson (1967) first made a detailed description of Portunus minutus based on a female from the Gulf of Thailand to compensate for the brief original description by Shen (1937), but did not make a comparison with L. innominatus . Recently, Spiridonov (1999) recorded two females from Ambon as P. innominatus and stressed that the determination of the taxonomic status of both species will be possible after reexamination and re-description of the type series. Takeda and Komatsu (2020) recorded a male and an ovigerous female from the Okinawa-jima Island, the Ryukyu Islands, as P. (L.) innominatus , and also three males, a female and an ovigerous female from Taiwan were recorded as L. minutus by Huang and Shih (2021) who mentioned the differences in the shallow front lobes of L. minutus and the G1 morphology. The shape of the front lobes seems to be similar in both species, and may be subject to individual variation; also, differences in the G1 are not clear. The dis- tributions of both species are almost sympatric as noted by Takeda and Komatsu (2020). The present report follows them in considering both species to be synonymous.

The following account of the carapace is based on the present male examined ( Fig. 9A ). The carapace dorsal surface is wholly covered with a thick coat of short setae; each protogastric region is provided with two transverse rows of minute granules along the anterior and median parts, which are united at the lateral end; the protogastric regions of both sides are isolated by a longitudinal median row of minute granules that reaches to the mesogastric region; a patch of minute granules on each side of the metagastric region and the cardiac region is indicated by a pair of low, granulated mounds arranged side by side. The frontal margin is cut into four shallow lobes, the inner pair being about half as wide as the outer pair. The carapace anterolateral margin is gently curved, with nine serrated teeth that are subequal or becoming slightly larger posteriorly; the last (epibranchial tooth) is about two times longer than the eighth tooth, directed laterally and weakly curved anteriorly, with the sharp tip. The basal half of the G1 is stout, and distal half tapers and strongly curved outwards ( Fig. 9B ).

Distribution. Lupocycloporus innominatus ranges from east coast of India to Indonesia, New Caledonia and the Ryukyu Islands, and L. minutus is recorded from almost the same area as L. innominatus , at depths of 6– 33 m. The present male was obtained at 60 m depth.

Figures

Fig. 9. A–B: Lupocycloporus innominatus (Rathbun), Ə (NSMT-Cr 30923; CB 15.1mm including lateral teeth, CL 10.5mm) from sta. 45. C–D: Charybdis (Archias) vadorum Alcock, Ə (NSMT-Cr 30920; CB 10.7×CL 7.6mm) from sta. 50. E–F: Thalamita sexlobata Miers, ovig.8 (NSMT-Cr 30926; CB 7.0×CL 6.0mm) from sta. 45.