Petrarctus veliger, Holthuis, 2002

Holthuis, Lipke B., 2002, The Indo-Pacific scyllarine lobsters (Crustacea, Decapoda, Scyllaridae), Zoosystema 24 (3), pp. 499-683 : 541-551

Petrarctus veliger n. sp.

( Figs 15-17 )

TYPE MATERIAL. — Holotype: 19 mm, RV Anton Bruun, cruise 1, stn 38 ( USNM); paratypes: 1 18 mm, 1 ov. 17 mm ( ZRC 2001.0326 ).

TYPE LOCALITY. — Andaman Sea, off South Burma, 14°07’N, 97°05’E, 69- 73 m.

ETYMOLOGY. — The specific name veliger is Latin, meaning sail-bearer, in reference to the very high cardiac and gastric teeth towering above the body.

MATERIAL EXAMINED. — Andaman Sea. Off South Burma, IIOE, RV Anton Bruun, cruise 1, stn 38, 14°07’N, 97°05’E, trawl, 69-73 m, 30.III.1963, 1 holotype, 19 mm ( USNM).

Philippines. Bohol, Balicasaq Id, off Panglao Id, c. 200-300 m, tangle nets, XII.2000, from local fishermen, 1 18 mm, 1 ov. 17 mm ( ZRC 2001.0326). DISTRIBUTION AND HABITAT. — There are only two depth records for this species: 69-73 m (Andaman Sea) and c. 200-300 m (Philippines). So far the species is only known from the types.

DESCRIPTION

The body is very robust, heavy and rough. The tubercles are quite high and the grooves and depressions deep.

The rostrum is bluntly rounded and bears a short and blunt tubercle, which is about as large as the tubercle found on the extreme inner part of the ophthalmic somite. There is no pregastric tooth, but the gastric tooth is very high and triangular ending in a single sharp point. The posterior surface of the gastric tooth is flattened and delimited by two curved rows of three or four tubercles, between which one or two smaller tubercles may be found. The posterior part of the gastric tooth is high and separated from the anterior part of the cardiac tooth by the cervical groove, which here forms a very narrow slit and curves up over the postrostral ridge. The cardiac tooth is even much higher and larger than the gastric, but of about the same shape. On its posterior margin it bears two rows of four or five distinct tubercles; the lateral surface of the cardiac tooth bears a few tubercles. On either side of the posterostral carina the cervical groove, which is very narrow on the ridge, strongly widens laterally forming a large smooth area between the postrostral and branchial ridges. The anterior submedian ridge lies close to the anterior postrostral ridge and ends in a distinct tubercle, which reaches about as far forward as the gastric tooth; it is followed by some smaller tubercles, some of which are interconnected. The intermediate row consists of four tubercles, the anterior of which jots out into the cervical groove; one or two tubercles are present between the anterior part of the intermediate row and the posterior branchial carina. The space between the anterior postrostral and the anterior branchial ridges shows very few tubercles apart from a transverse row of very small tubercles behind the anterior margin.

The branchial carina is widely interrupted by the cervical groove, the gap showing a distinct tubercle. The anterior branchial carina ends in the usual two teeth on the inner orbital margin; both teeth are sharply angled. Behind the posterior tooth the carina shows some three low tubercles. The orbital margin is finely tuberculate and between it and the branchial carina another tuberculated ridge is present. There are two postorbital tubercles. The intercervical ridge is covered by about 10 small, rather high tubercles. The posterior branchial carina ends anteriorly in a strong blunt tooth, behind which the carina bears two slightly diverging rows of tubercles; the inner row has three tubercles, the last of which being elongate and ridge-like; the outer row consists of five or six distinct tubercles. The anterior tooth of the lateral margin of the carapace is strong and followed by one or two more or less distinct anterolateral teeth. The anterior of the mediolateral teeth is triangular, the two or three following are rounded. The posterolateral margin bears five or six strong teeth which show some grooves; it ends in a group of tubercles. The marginal groove

FIG. 16.— Petrarctus veliger n. gen.,n.sp.,Andaman Sea off Burma, holotype carapace length 19 mm ( USNM) ; A, dorsal view; B, lateral view.

along the posterior margin of the carapace is quite distinct; before and behind it is a single row of tubercles. The posterior margin of the carapace has a blunt triangular median incision.

The first abdominal somite is entirely smooth and has no transverse groove, except for an indication of one near the base of the pleura. Also the longitudinal grooves are absent or only very vaguely indicated. The posterior margin of the somite shows a distinct blunt triangular median incision. Abdominal somites II to V have a distinct median longitudinal carina. The carina of somite II is lowest and shows a central groove in all but the anteriormost part; its lateral margin is lobulated. The median carina of somite III is highest, it is bluntly triangular and somewhat produced posteriorly, it slightly overhangs the posterior margin; it has an indistinct and interrupted median groove dorsally, and tubercles and short grooves on its lateral surface. The carinae of somites IV and V are lower, they are also slightly produced posteriorly. The tergites of somites II to V show a rather wide transverse median groove with a row of large tubercles before it, and behind it a broad transverse ridge, which in somites II and III has faint tubercles and is smooth in somites IV and V. The pleura of somite I have tubercles on the outer surface and three incisions in the lateral margin.

FIG. 17. — Petrarctus veliger n. gen., n. sp., Andaman Sea off Burma, holotype carapace length 19 mm ( USNM) ; A -E, pereiopods 1 to 5.

The pleura of the other abdominal somites end in a blunt top. Those of somite II show two wide transverse grooves, separated by rows of flat tubercles. In somites III to V there is only one transverse groove and two ridges; before the anterior ridge the surface of the pleuron is smooth. The sixth somite has a continuous transverse groove with a row of tubercles before it and three tubercles on the posterior margin.

The hard part of the telson shows four low and rounded tubercles: two anterior in the median area, and two more behind and more lateral. The teeth at the end of the hard part are placed in one line, the outer being widest.

The ophthalmic somite shows four distinct blunt tubercles, one on either side of the rostrum and one laterally.

The anterior margin of the antennular somite shows a strong triangular tooth in each half.

The sixth (last) segment of the antenna ends in six teeth. The outer is wide and blunt. The following four are narrow and taper gradually towards the top. The inner tooth is short and triangular and has a small incision at its base. The fifth segment is short and ends in two small teeth, the upper of which carries a carina. The fourth segment has a distinct oblique dorsal carina, which is somewhat curved at its base and carries a tubercle there. The carina traverses the segment in its middle and the outer and inner halves of the dorsal surface are of about equal width, they are deeply concave; there is no additional carina or row of tubercles in the outer half, sometimes there are a few scattered small tubercles. The outer margin of the fourth antennal segment bears two or three distinct teeth (the apical tooth of the segment excepted), sometimes an additional minute tooth is present distally. The anterior margin of the fourth segment bears a strong teeth mediad of the articulation with the fifth segment. The margin between this articulation and the apex of the segment bears one large tooth near the articulation and four smaller acute teeth on the rest of the margin.

The anterior margin of the epistome is triangularly incised in the middle, the two halves are convex.

The first pereiopod is robust. The dactylus is almost as long as the propodus. The surface of propodus and carpus is smooth with at most a few minor depressions. The outer surface of the merus has a wide ventral groove proximally and some depressions in the rest of the surface which thereby becomes rather rough. The second leg has the dactylus somewhat longer than in the other legs; dactylus, propodus and carpus are naked; the merus has a short dorsal hairy fringe and is rather roughly pitted. In P.3 the dactylus has a short dorsal hairy fringe, while the propodus has distinct dorsal and ventral fringes. The carpus has a dorsal area of hairs and does not carry a spur. P.4 and P.5 have hairs on the dorsal surface of the dactylus and the distal part of the propodus. The merus of P.2 to P.5 has dorsal hairs which are placed more densely in the posterior than in the anterior legs. A groove in the dorsal part of the outer surface of the merus, if present, is very inconspicuous.

The anterior end of the sternum is U-shapedly concave with a median incision flanked on each side by an inconspicuous tubercle. The anterior margin is slightly swollen. On either of the anterolateral teeth there is a V-shaped carina, which narrows anteriorly and ends abruptly some distance behind the top of the anterolateral tooth. The central part of the sternum is deeply concave and somewhat pitted; at the borders of the sternites it is somewhat sunken. In the male specimen a small median tubercle is present on somites II to V; in the female only the one on the fifth somite is discernable. The elevated sides of the sternum along the bases of the legs show an intricate pattern of rounded knobs and grooves. The posterior margin of the sternum is straight.

Size

The carapace length of the examined specimens lies between 17 and 19 mm. The ovigerous female has cl. 17 mm.

Colour

In the preserved specimens almost all traces of the coloration have disappeared, except for the specimens from the Philippines, which show a very indistinct darkish rounded median spot on the smooth anterior part of the first abdominal somite.

REMARKS

The species is only known from the three specimens cited above. No details are known about colour, habitat, variation, etc.

P. veliger n. sp. is most closely related to P. brevicornis n. comb., but can be distinguished by the very high cardiac and gastric teeth, the presence of four tubercles on the ophthalmic somite, the small number of lateral teeth on the fourth antennal segment, etc.

Petrarctus demani ( Holthuis, 1946) n. comb.

( Figs 18 ; 19 )

Scyllarus demani Holthuis, 1946: 91 , pl. 7 fig. d, pl. 8 fig. b, pl. 9 fig. a. — Burukovsky 1974: 106; 1983: 149. — Ritz 1977: 229, 231, figs 1-6. — Phillips et al. 1980: 69; 1981: 418, 422. — Barnett et al. 1986: 599, fig. 2. — Sekiguchi 1986a: 1290; 1987a: 331; 1987b: 415, 417; 1989b: 457; 1990a: 113; 1992: 212. — Barnett 1989: 124, fig. 1. — Phillips & McWilliam 1989: 357, 358. — Ito & Lucas 1990: 144, figs 1- 10. — Jones 1990: 181. — Sheehy, 1990: 618. — McWilliam et al. 1995: 564. — Burton 1996: 499, 503, figs 14-16.

Scyllarus tuberculatus – Nobili 1903: 12. — De Man 1924: 53, fig. 18 [non Arctus tuberculatus Bate, 1888 = Petrarctus rugosus (H. Milne Edwards, 1837) n. comb.].

TYPE MATERIAL. — Holotype:, H. Van der Horst leg., 1912 ( ZMA).

TYPE LOCALITY. — Indonesia. Banka Id, East of Sumatra.

MATERIAL EXAMINED. — Singapore. Received 31.VII.1902, E. Deschamps leg., 1 13 mm, 1 14 mm, 4 juv. 7-8 mm ( USNM).

Sarawak. Borneo, W of Tandjong Sirik, RV Lanessan, 2°40’N, 110°39’E- 2°38’N, 110°29’E, A. Krempf No. 35, 5.IX.1926, 1 24 mm (MNHN-Pa 795).

Indonesia. Banka Id, East of Sumatra, 1912, H. Van der Horst leg., 1 holotype ( ZMA). — Jedan, Aru Ids, dredged, 10.II.1907, P. N. Van Kampen leg., 1 19 mm ( ZMA). — Off west coast of Wasir Id, Wokam, Aru Ids, Mariel King Memorial Expedition, stn AWI/HS, 5°30’S, 139°12’E, 55-59 m, mud, 15.VI.1970, 1 juv. 6 mm ( WAM 251-70).

Australia. Western Australia, Shark Bay, 1964, E. Barker leg., 2 19 and 22 mm, 1 non-ov.

21 mm, 4 ov. 22-27 mm ( WAM 93-66 ) ; 15.X.1964, 1 ov. 26 mm ( WAM 95-66 ) ; 20.X.1964, 1 ov. 24 mm ( WAM 96-66 ). — RV Lancelin, in prawn trawl, 17.IX.1957, 2 21 and 24 mm, 1 24 mm ( WAM 65-58 ). — FV Bluefin, VII.1963, W. Poole, 1 25 mm, 2 19 and 23 mm ( WAM 94-66 ). — FV Bluefin, trawled, IX.1963, W. & W. Poole, 1 25 mm ( WAM 325- 64 ). — IV.1957, G. K. Bowen leg., 1 20 mm, 1 18 mm ( WAM 327-64 ). — In prawn trawl, 7.XI.1970, D. A. Ritz, 1 24 mm, 2 ov. 25 and 26 mm ( WAM 1-71 ). — FRV Péron, haul 1, 1.III.1962, 2 ov. 25 and 27 mm ( WAM 319-64 ). — FRV Péron, haul 5, 2.III.1962, 1 20 mm ( WAM 321-66 ). — FRV Péron, haul 105, 14.VI.1962, 1 24 mm ( WAM 326-64 ) ; VI-VII.1961, Poole brothers, 2 19 and 23 mm ( WAM 330-64 ). — RV Lancelin, trawled, R. McKay, 1 19 mm ( WAM 320-64 ). — CSIRO, Danish seine, 1 25 mm, 1 juv. 13 mm (AM-P12482). — Hopeless Reach, FRV Péron, 25°40’S, 113°45’E, 1.X.1965, 3 ov. 21-25 mm ( WAM 239-700 ). — Denham Sound, Shark Bay, c. 25°35’S, 113°15’E, trawl, 2-11 m, VII. 1955, 1 20 mm, 1 non-ov. 26 mm, 2 ov. 24 and 27 mm ( WAM 333-64 and 166/7-57). — Near Homestead, Shark Bay, FV Davena, Honolulu dredge, 11 m, VI. 1960, 1 22 mm ( WAM 332-64 ). — Carnarvon, 16.V.1979, J. C. Miquel leg., 4 18- 22 mm, 1 23 mm ( RMNH D 32258 ). — 40 miles SW of Carnarvon, trawled, VI.1960, A. Snell, 1 22 mm ( WAM 328-64 ). — Exmouth Gulf or Shark Bay, FRV Péron , 1960, R. McKay, 1 17 mm ( WAM 329-64 ). — Between Shark Bay and Onslow , trawled, 1966, W. & W. Poole, 1 juv. 5 mm ( WAM 236-70 ) .

East end of Mary Ann Passage, off Onslow, FV Davena, dredged, 13 m, 15.V.1960, B. R. Wilson, 1 20 mm ( WAM 324-64). — SE of Rosemary Id, Dampier Archipelago, dredged, 5-9 m, sand and shells, 26.VIII.1961, G. W. Kendrick & B. R. Wilson, 1 16 mm ( WAM 331-64). — NE of Mallus Id, FV Davena, Honolulu dredge, 18 m, 31.V.1960, R. D. Royce, 1 12 mm ( WAM 394-64). — Off Gantheaume Point near Broome, dredged, 7 m, VIII.1929, 1 ov. 21 mm ( AM). — Near entrance of Roebuck Bay, dredged, 9-15 m, Lithothamnion reef bottom, 26.IX.1929, 1 23 mm ( AM).

NW Coast. FV Dorothea , c. 21.5 miles ENE of Troughton Id, 13°45’S, 126°09’E, 59 m, mud, 23.X.1962, R. W. George, 1 17 mm ( WAM 323- 64).

Northern Territory. Darwin, 20 miles 320°, 4.IX.1965, E. Barker, 1 24 mm ( WAM 101-66). — Darwin, trawled, IX.1975, E. Barker, 1 ov. 25 mm ( WAM 231-70). — Chambers Bay, Darwin, FV Paxia , 13 m, 7.XI.1959, V. Wells, 1 ov. 25 mm ( WAM 335-64).

Queensland. SE corner of Gulf of Carpentaria , FV Rama , stn 1527, up to 22 m, XI.1964, R. W. George, 1 21 mm ( WAM 98-66 ) ; stn 1540, up to 22 m, 3 ov. 23-26 mm ( WAM 97-66 ) ; stn 1541, up to 22 m, 1 22 mm ( WAM 99-66 ) ; stn 1542, 1 ov.

24 mm ( WAM 100-66). — Trawled, 21 m, sandy mud bottom, 20.II.1983, C. Jones, 1 24 mm ( RMNH D 39342). — Trawled, 15 m, soft muddy bottom, 16.III.1983, C. Jones, 1 26 mm ( RMNH D 49591). — Wellesley Ids, 5 m, 13.II.1983, C. Jones, 1 14 mm ( RMNH D 39341). — Off Karumba, trawled, less than 26 m, XII.1963, J. C. Yaldwyn, 2 19 and 20 mm, 1 non-ov. 23 mm, 1 ov.

21 mm ( RMNH D 49594).

NE Gulf of Carpentaria. Trawled, 14 m, soft muddy bottom, 15.III.1983, C. Jones, 1 ov. 25 mm ( RMNH D 49592).

East coast of Queensland. Off Cairns, about 16°55’S, 145°46’E, trawl, 24 m, soft muddy bottom, 16.V.1984, C. Jones, 1 24 mm, 1 22 mm ( RMNH D 49593). — Off Cairns, trawled, 26 m, soft muddy bottom, 18.V.1984, C. Jones, 1 25 mm

C

B

( RMNH D 49594). — Between Cape Gloucester (about 20°04’S, 148°27’E) and Cape Cleveland (19°11’S, 147°01’E), RV Challenge, CSIRO, trawled, 18-46 m, K. de Witte, 1 24 mm (AM P.12992). — 7 miles NNE of Bowen, RV Endeavour, stn E 3098, 20°01’S, 148°14’E, 29 m, 2 19 and 24 mm (AM P.3518). — Bowen Harbour, Port Denison, about 20°02’S, 148°15’E, F. H. Rainford, 1 juv. 11 mm (AM P.6017). — Between Hayman Id (20°03’S, 148°53’E) and Eshelby Id (20°02’S, 148°37’E), Cumberland Group, RV Challenge, trawl, 37-46 m, K. de Witte, 1 ov. 18 mm (AM P.12988). — SE of Mackay, 21°09’S, 149°12’E, dredged, 24.II.1964, W. Goode, 1 ov. 24 mm ( WAM 334-64). — Great Sandy Id (= Fraser Id), Platypus Bay, RV Endeavour, stn E 3111, 25°15’S, 153°10’E, 9-16 m, 1 23 mm, 1 24 mm ( AM). — Platypus Bay, RV Endeavour, 28.VII.1910, 2 23 and 25 mm (AM P.3525). — Off Tin Can Bay, 25°49’S, 153°01’E, 46 m, P. T. Garrard, 1 24 mm ( AM). — Tin Can Bay, S end of Great Sandy Str., prawn trawl, P. T. Garrard, 1 27 mm (AM P.12990). — Moreton Bay, II.1967, A. J. Bruce, 2 22 and 23 mm, smallest ov. ( RMNH D 23379).

DISTRIBUTION. — The species has been found in several localities in the Malay Archipelago ( Sarawak, Singapore, Banka and the Aru Ids), and is taken in considerable numbers along the coasts of Western Australia (from Shark Bay north), Northern Territory, and Queensland (from Moreton Bay north). Nobili (1903: 12) reported it from Singapore, incorrectly assigning it to Scyllarus tuberculatus ( Bate, 1888) . De Man (1924) brought a specimen from Banka to the same species; Holthuis (1946) based his new species on De Man’s (1924) material, so that Banka, E of Sumatra, is the type locality. Ritz (1977) described phyllosoma stages 1 to 6 from Shark Bay, from the Gulf of Carpentaria and Moreton Bay; he had also described adult material from Shark Bay. Jones (1990) listed many specimens from Shark Bay (Homestead, Carnarvon and SW of it, Denham Sound, Hopeless Reach, between Shark Bay and Onslow, and material originating either from Shark Bay or Exmouth Gulf), all of this material has been examined for the present paper. Barnett (1989) mentioned the species from N Queensland, and Burton (1996) studied the sperm of material from the east coast of Queensland. McWilliam et al. (1995) gave the Australian range of the species as Western Australia to S Queensland, including Torres Strait, from where the species had so far not been reported. Barnett et al. (1986) and Ito & Lucas (1990) reported larvae from off Townsville, Queensland at about 19°S, 147°E. Phillips & McWilliam (1989) reported a final (gilled) phyllosoma stage of this species from 20 km off the SW coast of Oahu, Hawaiian Ids.

HABITAT. — The species has been reported from depths between 5 and 59 m; more than two thirds of the records are from 10 to 25 m. The species was found on bottoms described as: soft mud, sandy mud, mud, sand and shells, lithothamnion reef (in this order of frequency).

DESCRIPTION

The rostrum is not very narrow, the anterior margin is convex or bilobed, it is constricted behind the top. The dorsal surface bears a distinct rostral tooth. Apart from the rostral tooth there are two more teeth in the median line of the carapace. The cardiac tooth is very high, single or twotopped and overhangs the cervical groove; behind it there is a row of four to seven double tubercles. The gastric tooth ends in a single blunt point, it is likewise strong and forwards directed; behind it is a double row of three or four tubercles, the posterior pair being separated from the anterior by a distinct incision so that it seems as if two teeth are placed here, one right behind the other. A few tubercles are seen behind the rostral tooth. The branchial carina is deeply and rather narrowly interrupted by the cervical groove; there is no tubercle in the gap, but two tubercles are placed in the groove to the inner side of the gap. Anteriorly the branchial carina ends in two blunt teeth that are placed, one behind the other, on the inner orbital margin. There are several very inconspicuous tubercles on the anterior branchial carina; one or two of these are placed behind the anterior of the two teeth and two to four behind the second. The posterior branchial carina ends anteriorly in a distinct tooth behind which there are posteriorly diverging rows of distinct and high tubercles; the inner row contains four to seven, the outer seven or eight tubercles. The posterior submedian carina is short and bears two to five tubercles; between it and the posterior postrostral carina there are one or two additional tubercles. The intermediate row consists of three tubercles, between it and the posterior submedian ridge there is a transverse row of two or three tubercles. The anterior submedian ridge bears one or two tubercles, behind it, just before the cervical groove, another tubercle is visible. A short ridge is placed laterally of and slightly more anterior of the anterior submedian ridge. A row of three tubercles extends along the inner side of the posterior branchial carina, this row sometimes ends anteriorly in a small group of small tubercles just before the cervical groove. The lateral margin of the carapace shows two to four distinct anterolateral teeth, two to four mediolateral and eight to 10 posterolateral. Between the posterolateral margin and the posterior branchial carina several large tubercles are present. The intercervical ridge is longitudinal and carries three to seven tubercles; a tubercle is present more medially. There are two or three postorbital tubercles. The marginal groove along the posterior margin of the carapace is deep and rather wide; before it is a double and behind it a single transverse row of tubercles. The posterior margin of the carapace is triangularly incised in the middle.

The first abdominal somite shows a transverse groove, which extends over the full width of the segment; before this groove the somite is smooth, behind it there are a few pits. The anterior half of the following four somites is smooth; the posterior half shows a distinct median carina, which is extremely high in the third somite, where it is wide with tubercles on either side. The carina of the second somite is about half or less than half as high and almost as broad as that of the third, it shows a median dorsal groove and bears lateral tubercles. The median carinae of somites IV and V are sharply set off, narrow, less than half as low as that of somite II, and tuberculate dorsally. The carina of somite IV ends in one or two, that of somite V in a single median point. The posterior margin of somites I to III is incised in the middle, but otherwise entire; in somites IV and V the posterior margin bears 11 to 16 distinct small teeth. A broad transverse groove extends over the posterior half of somites II to V from the median carina to the tip of the pleura; on each side of this groove there is an elevated carina, which also extends to the tip of the pleura. On these carinae there are very distinct tubercles. In the lateral part of the tergite of somites II and III, the anterior carina bears elongate and forked tubercles. The pleuron of the first somite is divided into two lobes, the distal margin of the anterior lobe being again subdivided. The tips of the abdominal pleura are blunt and directed ventrally. The anterior margin of the second pleuron has a large lobulated tooth in the basal part, its distal part is serrate. The posterior margin of the pleura of somites II and III, sometimes also of IV, is entire in the proximal half, serrate in the distal, in somite V, and sometimes also in IV, it is entirely serrate. The anterior margin of the pleura of somites III to V is entire, or obscurely serrate. The upper surface of the sixth abdominal somite shows low tubercles, its posterior margin is denticulate.

The hard part of the telson shows two pairs of tubercles. The anterior pair is placed in the submedian region, the tubercles of the posterior pair are wider apart and about as large as the anterior. The posterior margin of this calcified part has the inner of the two pairs of teeth rather narrow and blunt, they reach farther back than the outer, which are broader and about rectangular.

The anterior margin of the antennular somite is produced forward in each half to a blunt low tooth; between this tooth and the median line of the somite there usually are some incisions in the margin.

The anterior margin of the distal (sixth) segment of the antenna is almost straight and rectangularly placed on the inner margin. It bears five or six broad teeth with broadly rounded tops. The inner margin bears a single triangular tooth. The antero-internal angle of the fifth segment ends in two teeth, the inner of which bears a dorsal carina. The fourth segment reaches beyond the sixth. Its anterior margin bears six to 10 small teeth, the inner of which, or the next, is largest. The outer margin of the fourth segment bears five to nine teeth of irregular size; these teeth are usually small and look more like serrations. The dorsal surface of the segment bears a strong median oblique carina, no additional carinae or rows of tubercles are found on the outer half of the segment.

The anterior margin of the epistome is concave without a median incision.

The first pereiopod is distinctly more robust than the second; the propodus bears no dorsal hairy fringe. The dactyli of P.1 and P.2 are naked, that of P.2 is much longer than either that of P.1 or P.3, but it is less than twice as long as that of P.4. The dactyli of P.3 to P.5 have an extremely short pubescence in the basal part and some longer hairs in the proximal part of the upper surface. The propodus of P.3 is not flattened and not or hardly broader than that of P.2 or P.4, it bears a dorsal fringe of hairs, which lacks in the other legs. No ventral hairy fringe is visible in the propodus of any of the legs. A dorsal hairy fringe is furthermore present on the carpus of P.3 to P.5, and on the merus of all legs. The outer surfaces of all segments of P.3 to P.5 bear longitudinal rows of short stiff hairs. P.1 and P.2 have the distal three segments naked. There are no hairy grooves on the propodus of any of the legs; such a hairy groove is present on the merus, though it often is indistinct.

The anterior margin of the thoracic sternum is V- or U-shapedly emarginate with a narrow incision in the middle. The oblique carinae running back and slightly inwards from the anterolateral teeth do not meet. In large specimens a median tubercle is present on the anterior margins of somites II to V of the sternum; each forms the central point of a transverse row of smaller tubercles. The posterior margin of the sternum is tuberculate in the males, smooth in the females.

The first pleopods of the male (implanted on the second abdominal somite) are well-developed, the following pleopods are rudimentary, the branches being mere buds; in some cases either the endopod or the exopod are somewhat leafshaped.

Size

Of the examined specimens cl. varied from 5 to 27 mm. In the juveniles cl. was 5 to 11 mm, in the males 13 to 25 mm (with more than half between 20 and 25 mm), in the non-ovigerous females cl. was 14 to 27 mm, most between 20 and 27 mm. In the ovigerous females cl. was 18 to 27 mm in more than half between 24 and 26 mm. Sheehy (1990) reported on specimens with cl. 24.5 to 28 mm.

Colour

A specimen from Shark Bay, Western Australia ( WAM 94-66), showed remnants of the original colour pattern. The most conspicuous is a dark circular spot in the middle of the upper surface of the first abdominal somite. An irregular longitudinal dark band extends either side of abdominal somites I to III just above the base of the pleura, these bands are narrow on somite I, widen posteriorly, and join in the middle of somite III. They also extend onto the pleuron of abdominal somite II and on the posterior part of pleuron III. On the antennae a dark spot was seen in the inner distal part of segment VI and in the outer basal part of segment IV. A dark ring is seen slightly behind the middle of the propodus of P.3 to P.5.

Larvae

The larval development of this species has been studied by several authors: Ritz (1977) described the first to sixth phyllosoma stages. Ito & Lucas (1990) described and figured the complete larval development after material from off Townsville, Queensland. Barnett (1989) provided a description and figures of the last phyllosoma stage, while the nisto stage, taken from the plankton at a depth of 20-0 m off Townsville, was described and figured by Barnett et al. (1986). Larvae were also discussed by Phillips et al. (1981), Phillips & McWilliam (1989) and McWilliam et al. (1995). Burton (1996) studied spermiomorphism of the species.

Figures

FIG. 15. — Petrarctus veliger n. gen., n. sp., Andaman Sea off Burma, holotype carapace length 19 mm (USNM); A, dorsal view; B, lateral view. J.-F. Dejouannet del.

FIG. 16.— Petrarctus veliger n. gen.,n.sp.,Andaman Sea off Burma,

FIG. 17. — Petrarctus veliger n. gen., n. sp., Andaman Sea off Burma,

FIG. 18. — Petrarctus demani (Holthuis, 1946) n. comb., Carnarvon, Western Australia, 14.V.1979, J. C. Miquel; A, dorsal view; B, lateral view; C, thoracic sternum.

FIG. 19. — Petrarctus demani (Holthuis, 1946) n. comb., Carnarvon,Western Australia, 14.V.1979, J. C. Miquel; A-E,