Crenarctus bicuspidatus Holthuis 2002, n. comb.
Creators: name: Holthuis, Lipke B.
Publisher: name: Zenodo
Year: 2002
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Decapoda
Scyllaridae
Crenarctus
Crenarctus bicuspidatus

description: Crenarctus bicuspidatus (De Man, 1905) n. comb.   
(Figs 64; 65; 69F)  
 Arctus bicuspidatus De Man, 1905: 589.   
 Scyllarus bicuspidatus – De Man 1916: 80, pl. 2 fig. 12. — Parisi 1917: 9. — Holthuis 1946: 95, pl. 7 fig. e. — Harada 1962: 111, text-figs 1, 2, pl. 10, pl. 12 fig. 15, pl. 13 fig. 19, pl. 14 fig. 21; 1965: 36, fig. 1 e-g. — Shojima 1963: 350. — Saisho 1964: 1, fig. 1; 1966: 177, 194, 196, figs 4, 5. — Utinomi 1967: 117. — Robertson 1968: 333. — Holthuis & Sakai 1970: 92. — Nishimura & Suzuki 1971: 89. — Bardach et al. 1972: 647. — Burukovsky 1974: 107; 1983: 150. — Tampi 1976: 561. — Phillips et al. 1980: 69; 1981: 418, 422, 427, figs 4, 11, 13, 14. — Phillips & Sastry 1980: 34. — Van Olst et al. 1980: 336. — Miyake 1982: 85. — Polz 1984: 35. — Sekiguchi 1986a: 1289-1291; 1986b: 15, 17; 1986c: 289, 293-295, figs 4-6; 1987a: 331; 1987b: 415-418, fig. 49; 1988: 3; 1992: 212. — Pearce et al. 1992: 1, 9, fig. 7c. — Yamaguchi 1993: 588. — Yamaguchi & Baba 1993: 254, fig. 61. — Fransen et al. 1998: 66.   
 Non Scyllarus bicuspidatus – Jones & Morgan 1993: 148. — McWilliam et al. 1995: 564 (= Crenarctus crenatus n. comb.).   
 Scyllarus Arctus var. – De Haan 1841: 154.   
 Scyllarus Arctus var. a – Herklots 1861: 142.   
 ? Scyllarus sp. A – M. W. Johnson 1971b: 262, fig. 47- 56.   
 Scyllarus sp. – Lovett 1981: 95, fig. 195.   
 TYPE MATERIAL. — Holotype: 7.5 mm, Siboga Expedition, stn 310 (ZMA).   
TYPE LOCALITY. — Indonesia. Flores Sea, 8°30’S, 119°7.5’E, 73 m.  
 MATERIAL EXAMINED. — South Africa. Natal, off Port Durnford, 28°55’S, 31°50’E, 20 m, in stomach of catfish Tachysurus feliceps (Valenciennes, 1840), 23.VI.1970, P. F. Berry leg. et don., 1 12 mm, 1 20 mm, in poor condition (RMNH D 49562).   
 Madagascar. 1 ov. 20 mm (MNHN-Pa 302). — Near Fort Dauphin, SE Madagascar, 25°04.8’S, 46°55.7’E, trawled, 28 m, 4.III.1973, RV Vauban, stn CH 74, 1 juv. 6 mm (MNHN-Pa 582).   
 Japan. Wakayama Prefecture, off Taiji, F. Yanagisawa leg., 1 specimen 20 mm (SUF). — Moriura Bay, Taiji, 20.XII.1981, F. Yanagisawa leg., 1 juv. 12 mm (SUF). — Nachikazaki, Kii Peninsula, scuba diving, 2 m depth, 14.VI.1973, K.-I. Hayashi leg. et don., 1 16 mm (RMNH D 38517).   
 Okino Shima S 79°W, 75 miles, 34°16’N, 130°16’E, RV Albatross, stn D 4880, 108 m, fine grey sand and broken shells, 2.VIII.1906, 1 16 mm (USNM).   
Off Sone, Munakata-oshima, Fukuoka Prefecture, 3.VII.1957, Y. Motomatsu leg., 1 13 mm, 1 11 mm (ZLK).  
Japan (possibly near Nagasaki), 1823-1834, P. F. von Siebold & H. Bürger leg., 1 25 mm, dry (RMNH D 5513).  
 Indonesia. Flores Sea, 8°30’S, 119°7.5’E, Siboga Expedition, stn 310, 73 m, bottom sand with few pieces of dead coral, 12.II.1900, 1 juv. holotype 7.5 mm (ZMA).   
 New Caledonia. Nouméa, IX.1890, navy chaplain, Abbé Culliéret leg., 1 17 mm (MNHN-Pa 1897).   
North of New Caledonia. MUSORSTOM 4, stn 187, 19°08.3’S, 163°29.3’E, 65-120 m, 19.IX.1985, 1 ov. 13 mm (MNHN-Pa 1154).  
LAGON. Lagon Est, stn 641, 21°53.0’S, 166°43.0’E, 50-52 m, 7-8.VIII.1986, 1 juv. 5 mm (MNHN-Pa 1190). — Stn 836, 20°46.4’S, 165°15.75’E, 57 m, 11.I.1987, 2 14 and 15 mm (MNHN-Pa 1280).  
Lagon Sud-Ouest, stn 112, 22°23’S, 166°48’E, 42 m, 22.VIII.1986, 1 11 mm (RMNH D 48755). — Stn 114, 22°24’S, 166°50’E, 37 m, 22.VIII.1984, 1 10 mm (MNHN-Pa 1024). — Stn 127, 22°31’S, 166°46’E, 55 m, 23.VIII.1984, 1 ov. 17 mm, 2 9 and 11 mm (MNHN-Pa 1028). — Stn 277, 22°17’S, 166°16’E, 30 m, 8.XI.1984, 1 juv. 5 mm (MNHN-Pa 1899). — Stn 336, 22°41’S, 166°51’E, 26 m, 28.XI.1984, 1 juv., 1 11 mm (MNHN-Pa 1207). — Stn 347, 22°43’S, 166°53’E, 46 m, 29.XI.1984, 1 juv. 5 mm (MNHN-Pa 1231). — Stn 385, 22°36’S, 167°10’E, 75 m, 22.I.1985, 1 11 mm (RMNH D 48754). — Stn 401, 22°32’S, 167°15’E, 49 m, 23.I.1985, 1 12 mm (MNHN-Pa 1214). — Stn 404, 22°37’S, 167°18’E, 35 m, 23.I.1985, 1 12 mm (MNHN-Pa 1271). — Stn 416, 22°38’S, 167°14’E, 40-50 m, 24.I.1985, 1  
9 mm, 1 juv. 6 mm (MNHN-Pa 1210). — Stn 424, 22°45’S, 167°24’E, 55 m, 25.I.1985, 1  
10 mm (MNHN-Pa 1217). — Stn 572, 22°52’S, 167°00’E, 65 m, 17.VII.1985, 1 juv. 6 mm (MNHN- Pa 1896).  
Île des Pins, stn 586, 22°48’S, 167°30’E, 57 m, 18.VII.1985, 1 ov. 12 mm (MNHN-Pa 1898).  
Canal Woodin. 22°24’S, 166°48’E, 30 m, 29.VII.1987, 2 10 and 14 mm (MNHN-Pa 1327).  
HABITAT. — The species has been obtained from depths between 2 and 108 m, most (75%) between 26 and 65 m. Only two descriptions of the bottom on which the species was found are known: fine grey sand with broken shells, and sand with few pieces of dead coral. Utinomi (1967) reported the species from low tide in a coral reef area.  
 DISTRIBUTION. — The species has a wide distribution which ranges from South Africa and Madagascar to Japan, Indonesia and New Caledonia. The type locality is in the Flores Sea, Indonesia, 8°30’S, 119°7.5’E (De Man 1905, 1916). The other records in the literature are all from Japan: Japan (De Haan 1841; Herklots 1861; Holthuis 1946; Holthuis & Sakai 1970; Nishimura & Suzuki 1971; Miyake 1982; Yamaguchi & Baba 1993; Yamaguchi 1993), Sagami Bay, Honshu (Parisi 1917), Tanabe Bay, Wakayamaken (c. 33°42’N, 135°22’E) (Harada 1962), Japan Sea near Mihonoseki, Honshu (c. 35°34’N, 133°19’E) (Harada 1962), Kanae Bay, Oita-ken, NE Kyushu (c. 38°54’N, 141°35’E) (Utinomi 1967), Nisi-no-umi, Amakusa, Kyushu (Harada 1962), Kaimon-cho, Kagoshima-ken, Kyushu (Saisho 1964). Larvae assigned with greater or lesser certainty to this species have been reported from an area off the Pacific coast of Japan between 32°20’- 34°45’44”N and 135°44’75”- 138°45’50”E (Sekiguchi 1986a), Kaimon-cho, Kagoshima-ken, Kyushu (Saisho 1964), from the entrance of Nagasaki Harbour, Kyushu, Japan (Shojima 1963) and from the area of the Marianas, 23°14.7’N, 150°16.0’E (Sekiguchi 1990a). Furthermore Sekiguchi (1990a: 245) considered the larvae described and figured by M. W. Johnson (1971b) as Scyllarus spec. A, collected in the South China Sea off the coast of Vietnam and in the mouth of the Gulf of Siam, to belong to the present species.   
DESCRIPTION  
The rostrum is rather broad and is hardly constricted behind the anterior margin. Dorsally it bears a distinct and sharp anteriorly directed rostral tooth. Sometimes a tubercle can be seen on the back of this tooth. Apart from the rostral tooth there are two more teeth in the median line of the carapace. The cardiac tooth is twotopped and divided in two by a longitudinal groove; it is followed by a double row of three or four tubercles. The pregastric tooth is welldeveloped, single and pointed; it bears posteriorly a double row of five tubercles, the third pair of which are higher than the rest, often conspicuously so; they may represent the gastric tooth, which otherwise is absent. At each side of the double row of tubercles there is another single row. The branchial carina is rather widely interrupted by the cervical groove; the gap shows no tubercle. Anteriorly the carina bears the usual two teeth that are distinct and acute, and placed on the inner margin of the orbit; behind the posterior of these teeth there are three diverging rows of obscure tubercles. The posterior branchial carina ends anteriorly in a blunt tooth, behind which there is a double row of eight or nine flattened tubercles. The posterior submedian carina bears two or three longitudinal rows of one to three blunt tubercles. The intermediate row bears four tubercles. A large tubercle is placed between the intermediate row and the lateral carina. The anterior submedian carina bears a group of four to seven low indistinct tubercles of different size none of which is elevated and pointed. The anterolateral angle of the carapace is acute, behind it are four or five anterolateral tubercles, three mediolateral and a double row of eight or nine posterolateral tubercles. In the space between the posterior branchial and the posterior lateral carinae two tubercles are visible. The intercervical carina bears a group of one large and two to four small tubercles. The marginal groove along the posterior margin of the carapace is narrow and deep, there are two transverse rows of tubercles both before and behind it; the latter are not very distinct. The posterior margin of the carapace is shallowly incised in the middle. The dorsal surface of the carapace has a cover of short hairs between the tubercles; slightly behind the anterior margin of the carapace there is a narrow naked strip, which gives the impression of a groove, extending behind the rostrum over a large part of the carapace.  
 The first abdominal somite has a complete transverse groove extending over its full width. Before the groove the somite is smooth, behind it are about 24 distinct longitudinal grooves, most are single, a few are forked. The anterior half of the following somites is smooth but for a transverse crenulated or irregular groove carrying a row of short hairs. The posterior half of the somites shows no median carina, but only the usual arborescent pattern of narrow and deep grooves, that in the median area forms an elongate lobulated figure. This median lobulated area of the second somite is not elevated anteriorly, but is flush with the rest of the surface; this in contrast to the situation in C. crenatus n. comb. The posterior margin of somites I to IV are deeply incised in the middle; the median part of the posterior margin of somites V and VI is broadly and bluntly produced. The pleura of the first abdominal somite are short and bilobed. Those of the second somite are broad and end in a small sharp point, which, however, is not tooth-like produc- ed; the anterior margin shows an indistinct lobe, but the rest of the margins is entire or slightly serrate. In the pleura of the third and fourth somites the tip is directed slightly posteriorly, in the fifth it is about rectangular. The sixth abdominal somite and the hard part of the telson show squamiform tubercles of various sizes. The two pairs of teeth on the posterior margin of the hard part of the telson are acutely pointed; the inner pair is widest and reaches farther backward than the outer.   
The anterior margin of the antennular somite bears four distinct rounded teeth.  
The last (sixth) segment of the antenna is rather narrow. The anterior margin is convex and bears six teeth, the inner five of which gradually taper to a rounded tip; the inner margin bears one tooth. The antero-internal tooth of the fifth segment bears a dorsal carina. The anterior margin of the fourth segment shows three to six teeth, the innermost of these is longest and unequally two-topped, the inner being the smaller. The rest of the teeth are of irregular size, but much smaller than the first. The outer margin of the fourth segment bears two teeth (the apical tooth not includ- ed). The median carina of this segment is strong and there are no additional carinae or rows of tubercles on the upper surface. The anterior margin of the basal segment of the antennal peduncle ends in a narrow point.  
The anterior margin of the epistome is incised in the middle.  
P.1 is distinctly more robust than P.2. The dactyli and propodi of P.1 and P.2 are naked; in the other legs the dactyli show an extremely short pubescence in the basal part. The dactylus of the second leg is longer than that of any of the other legs, and is somewhat less than twice as long as that of the fourth. The propodus and carpus of P.3 have a dorsal fringe of hairs. The carpus of P.4 has a row of hairs in the extreme distal part of the upper margin. The other legs show no hairy fringes on the dorsal margin of either propodus or carpus, while in none of the legs there is a hairy fringe on the ventral margin of the propodus. The propodus of P.3 is somewhat compressed, but it is not conspicuously broadened, being about as wide as the merus; it has two hairy grooves on the outer surface. On the propodus of P.4 there is one hairy groove; such a groove is also present on the carpus of P.3 to P.5. The meri of all legs have a dorsal fringe of hairs, while the outer surface of the merus carries two hairy grooves (in P.2 and P.3), or one (in P.4 and P.5). The anterior margin of the thoracic sternum is emarginate, U-shaped, the antero-lateral teeth reach far beyond the central part, and sometimes have a corneous tip. The central part of the margin shows a deep median incision, at either side of which there is a low tubercle. The median incision continues posteriorly as a groove which is flanked by two ridges; these ridges end behind the anterolateral teeth in a blunt tooth. A median tubercle is placed on the fifth thoracic sternite. The posterior margin of the sternum, both in males and females, is unarmed, but makes a sharply triangular curve just behind the base of P.5.  
The first pleopods of the male are normal in shape. In the following pleopods the endopods are rudimentary, while the exopods are rather small and leaf-shaped.  
 Size   
The examined males had cl. 10 to 17 mm, the non-ovigerous females had cl. 7.5 to 25 mm, the ovigerous females had cl. 12-20 mm, while the specimens of less than 7 mm were considered juvenile. Parisi’s (1917: 9) female had cl. 24 mm. Harada (1962: 111) mentioned a male with cl. 11.8 mm, and 4 ovigerous females with cl. 17.3 to 22.4 mm. The specimen (of unknown sex) examined by Utinomi (1967) had cl. 18 mm.  
 Colour   
 The type specimen was described by De Man (1916: 84) as follows: “This specimen presents a uniform yellowish colour; the smooth, underlying part of the 1st abdominal tergum is marked with a dark fleck in the middle, nearly as in Scyll. sordidus, but less distinctly defined and a dark fleck exists also near the inner border of the distal antennal squame”. Parisi (1917: 9) observed in his material a dark spot in the anterior part of the first abdominal somite, and spots of a similar colour on the side of the carapace in the anterior branchial region; the latter, however, had almost disappeared through the action of the alcohol.   
A colour photograph made of the female from LAGON stn 836 (Lagon Est, New Caledonia, 11.I.1987) shows a rather uniform pale orange brown animal. A large dark reddish brown broadly oval spot is visible on the anterior half of the first abdominal somite. This spot is surrounded by a wide pale ring. A striking short dark stripe is present on the fourth antennal segment. The antennulae and the inner margin of the antennae are spotted with dark dots. On the carapace a few paler areas show, but this may be due to light effects during the photography. The tailfan and the sixth abdominal somite are whitish. Of the pereiopods that are visible in the photograph, the propodus and merus have the usual dark ring in the middle.  
 Larvae   
 Although in the literature many references are found to larvae of this species, there are only few original records. Saisho (1964: 1; 1966: 177, 194, 196, figs 4, 5) in 1964 described the first phyllosoma stage of the species, raised from the egg of an ovigerous female from Kaimon-cho, Kagoshima prefecture, Japan. In his 1966 paper Saisho discussed rearing of the species to the 9th instar, which was figured by him. Sekiguchi (1990a) described and figured the two last phyllosoma stages, and referred to M. W. Johnson’s (1971b) account of the larval Scyllarus spec. A, which he considered to probably belong also the present species. Phyllosoma stages I-IV and VII- IX supposedly of this species were reported by Pearce et al. (1992) from the Leeuwin Current off Geraldton, Western Australia; the younger stages were found closer to the coast than the older. The larvae from Australian waters consider- ed by them and by McWilliam et al. (1995) as belonging to the present species might well be actually C. crenatus n. comb.   
 Commensalism   
 Utinomi (1967) found a new species of pedunculate cirriped (Paralepas scyllarusi Utinomi, 1967) attached to the base of the uropod of a specimen of the present species.
description: Published as part of Holthuis, Lipke B., 2002, The Indo-Pacific scyllarine lobsters (Crustacea, Decapoda, Scyllaridae), pp. 499-683 in Zoosystema 24 (3) on pages 664-669, DOI: 10.5281/zenodo.4689240