Crenarctus bicuspidatus ( De Man , 1905 )

Yang, Chien-Hui, Lin, Chia-Wei & Chan, Tin-Yam, 2014, Additional slipper lobsters of the subfamily Scyllarinae Latreille, 1825 (Crustacea, Achelata, Scyllaridae) from Taiwan, Zootaxa 3852 (3), pp. 336-346 : 341-343

Crenarctus bicuspidatus ( De Man, 1905)

( Figs. 4 , 6 C)

Arctus bicuspidatus De Man 1905: 589 (type locality: Indonesia).

Crenarctus bicuspidatus .— Holthuis 2002: 664 , figs. 64–65, 69 F.—Chan 2010: 161, fig. F.— Kim et al. 2013: 117, figs. 3, 4, 11B–C.

Material examined. Kaohsiung City, Zuoying, R.V. “Ocean Researcher III”, 9 Jan 2003, 1 male 13.9 mm cl ( NTOU M01295 ). Penghu County, SCUBA diving, 21 Aug 2011, 1 male 11.8 mm cl (NMMBCD4007).

Diagnosis. Rostral and pregastric teeth present. Gastric tooth replaced by 2 tubercles. Cardiac tooth low and as 2 blunt tubercles. Orbital carina generally smooth and with 2 large teeth anteriorly. Medial incision on posterior margin of carapace deep. Abdomen with arborescent sculpture, without median dorsal carina. Posterior margin of abdominal tergites I–IV distinctly incised medially. Abdominal pleura II–IV each terminated in sharp point. Anterior margin of antenna segment VI bearing 6 or 7 large teeth. Antennal segment IV without additional carina, bearing 3–6 small teeth on anterior margin and 2 large teeth on outer margin. Dactylus of pereiopod II longest in all pereiopods. Propodus of pereiopod III bearing 2 parallel setose grooves. Anterior part of thoracic sternum with a large “U”-shaped notch, followed by a deep median suture, lateral angles strongly protruding forwards. Only last thoracic sternite bearing large median tubercle.

Coloration. Body generally dark greenish brown. Middle of abdominal tergite I bearing a large black spot with thick whitish brown rim. Eyes dark brown. Pereiopods pale yellowish with dark blue bands.

Distribution. Widely distributed in the Indo-West Pacific from South Africa to Japan and New Caledonia; at depths of 2– 108 m.

Remarks. The genus Crenarctus , containing only two species, is reported for the first time from Taiwan. Crenarctus bicuspidatus is a very widely distributed species and its general body color appears to have large variations. Photographs of New Caledonian ( Holthuis 2002) and Korean ( Kim et al. 2013: fig. 11B) specimens as well as an underwater photographs from an unspecified locality ( Humann & DeLoach 2010) show an orangish body. Another photograph of a Madagascan specimen (Chan 2010) shows a body color of half orange and half dull green. The coloration of the two Taiwanese specimens and a Korean specimen ( Kim et al. 2013: fig. 11C) are very similar and generally dark greenish brown. Nevertheless, all show a large median spot on the abdominal tergite I (though this spot is sometimes orange with a dark transverse band) and banded pereiopods.

Figures

FIGURE 4. Crenarctus bicuspidatus (De Man, 1905), male 13.9 mm cl (NTOU M 01295): A, carapace, dorsal view, with right anternnal segment IV deformed; B, abdominal tergties I-III, dorsal view; C, thoracic sternum; D, pereiopod I; E, pereiopod II; F, pereiopod III; G, pereiopod IV; H, pereiopod V. All right pereiopods. Scales = 5 mm.

FIGURE 6. A, Bathyarctus rubens (Alcock and Anderson, 1894), male 14.9 mm cl (NTOU M 01283); B, Chelarctus aureus (Holthuis, 1963), female 14.3 mm cl (NTOU M 01288); C, Crenarctus bicuspidatus (De Man, 1905), male 11.8 mm cl (NMMBCD 4007); D, Petrarctus veliger Hothuis, 2002, female 19.4 mm cl (NMMBCD 4008).