Portunus armatus (A. Milne-Edwards, 1861 )

Lai, Joelle C. Y., Ng, Peter K. L. & Davie, Peter J. F., 2010, A Revision Of The Portunus Pelagicus (Linnaeus, 1758) Species Complex (Crustacea: Brachyura: Portunidae), With The Recognition Of Four Species, Raffles Bulletin of Zoology 58 (2), pp. 199-237 : 219-222

publication ID

https://doi.org/10.5281/zenodo.5342701

persistent identifier

https://treatment.plazi.org/id/AC71483F-E179-FFC5-B7B6-FC29FA8AA076

treatment provided by

Diego

scientific name

Portunus armatus (A. Milne-Edwards, 1861 )
status

 

Portunus armatus (A. Milne-Edwards, 1861)

( Figs. 6D View Fig , 7D View Fig , 17 View Fig , 18 View Fig , 19 View Fig , 20D View Fig , 21D View Fig , 22D View Fig , 23D, 23H View Fig , 24D View Fig )

Neptunus armatus A. Milne-Edwards, 1861: 322 , Pl. 33, Fig. 2 View Fig .

Neptunus pelagicus – A. Milne-Edwards, 1873: 156.

Portunus pelagicus – Hale, 1927: 149-150, Fig. 150; Stephenson & Campbell, 1959: 96–98, Figs. 2A View Fig , 3A View Fig , Pl. 1 Fig. 1 View Fig ; McNeill, 1968: 54; Stephenson & Rees, 1967b: 34, 35 (part); 1968: 21; Stephenson, 1968b: 84, Fig. 1A–D View Fig , Pl. 11; Stephenson, 1972a: 15 (key); Stephenson, 1972b: 137 (part); Stephenson, 1976: 18; Healy & Yaldwyn, 1970: 86, Fig. 46; Türkay, 1971: 123 (part); Heath, 1973: 2 (key), 13, Fig. 4b View Fig ; Poupin, 1996: 32; Davie, 1998: 100 (col. Fig.); 2002: 467; Davie, 2005: 157; Rice, 1999: 222 (figure); Jones & Morgan, 2002: 157, 158 (top), 159 (top); Laboute & Richer de Forge, 2004: 401(top).

Portunus (Portunus) armatus – Ng et al., 2008: 152.

Type locality. – Shark Bay , Western Australia .

Material examined. – Lectotype of Neptunus armatus A. Milne- Edwards, 1861, male (36.0 × 15.0 mm) ( NHM 1858.172.115) (photograph examined), Shark Bay , Western Australia . Paralectotype – 1 male (34.0 × 16.0 mm) ( NHM 1858.172 .114) (photograph examined), Shark Bay , Western Australia. Others – AUSTRALIA : 1 female (133.3 × 61.4 mm) ( WAM C38994 View Materials ), Rottnest Island , Western Australia, otter trawl at 29 m, 32°02.43'S 115°31.67'E to 32°02.60'S 115°31'E, coll. A. Sampey, 27 Apr.2007 GoogleMaps ; 1 female (carapace length 72.5 mm, sides broken) ( WAM C38996 View Materials ), Southwest Cape , Western Australia, trawled at 37 m, 33°33.24'S 115°00.00'E to 33°37.98'S 114°59.99'E, coll. A. Sampey, 30 May 2007 GoogleMaps ; 1 male (85.4 × 41.0 mm) ( WAM C38995 View Materials ), Southwest Cape , Western Australia, trawled at 37 m, 33°37.59'S 115°00.13'E to 33°37.72'S 115°00.14’E, coll. A. Sampey, 30 May 2007 GoogleMaps ; 1 male (93.5 × 43.8 mm) ( WAM C38997 View Materials ), Southwest Cape , Western Australia, trawled at 37 m, 33°38.24'S 115°00.00'E to 33°37.98'S 114°59.99'E, coll. A. Sampey, 30 May 2007 GoogleMaps ; 2 juv. males (larger 34.0 × 14.5 mm) ( WAM C39101 View Materials ), Denham, Shark Bay , Western Australia, coll. B. R. Wilson, 29 Dec.1959 ; 2 juv. males (larger 26.8 × 10.9 mm) ( WAM C39179 View Materials ), Denham, Shark Bay, Western Australia, sand flats at low tide just north of Denham jetty, coll. B. R. Wilson, 29 Dec.1959 ; 1 juv. male (38.6 × 16.4 mm) ( WAM C39180 View Materials ), Monkey Mia, Shark Bay , Western Australia, coll. B. R. Wilson, 2 Jan.1960 ; 1 female (56.9 × 24.0 mm), 1 juv. male, (damaged) ( WAM C20194 View Materials ), Goulet Bluff, south of Denham , Shark Bay, W.A., coll. BTH, 7 Mar.1986 ; 1 juv. male (30.7 × 13.89 mm) ( WAM C20682 View Materials ), Kuri Bay, Kimberleys , Western Australia, UIRB G1 33, intertidal, coll. G. Morgan, 23 Aug.1991 ; 1 juv. female (48.2 × 27.4 mm) ( NHM), Cape Boileau , NW Australia, coll. B. Grey, 13 Mar.1930 ; 1 male (27.7 × 11.1 mm) ( QM-W20210 ), western side of Mermaid Is, Kimberley coast, Western Australia, 16°19'S 123°21'E, muddy reef flat, coll. J. W. Short, 18 Nov.1994 GoogleMaps ; 1 male (40.0 × 17.7 mm), 1 female (83.4 × 40.9 mm, one lateral tooth chipped) ( QM-W21064 ), Reveley Island, Cambridge Gulf, Kimberley Coast , Western Australia, 14°22'S 127°50'E, sand flat, in pools, coll. J. W. Short, 21 Nov.1995 GoogleMaps ; 1 male (49.8 × 19.9 mm) ( QM-W21203 ), Mackenzie Anchorage, Napier Broome Bay , south of Anjo Peninsula, W. A., 14°20'06"S, 126°30'03"E, rocky cove, pools, muddy sand, backed by Rhizophora mangroves, coll. J. W. Short, 24 Nov.1995 GoogleMaps ; 1 male (46.6 × 19.9) ( QM-W21247 ), West Governor Island, NW side, Napier Broome Bay, Kimberley Coast , Western Australia, 13°55'07"S 126°38'00"E, netted, coll. J. W. Short, 26 Nov.1995 GoogleMaps ; 1 male moult (75.5 × 31.1 mm) ( QM-W21267 ), Sandy Island, Cape Talbot, Kimberley Coast , Western Australia, 13°45'03"S 126°48'05"E, coll. J. W. Short, 27 Nov.1995 GoogleMaps ; Sandy Island, Cape Talbot, Kimberley Coast , Western Australia, 13°45'03"S 126°48'05"E, coll. J. W. Short, 28 Nov.1995 GoogleMaps ; 1 male (124.6 × 54.2 mm) ( SAM C15787 View Materials ) , 1 male (136.5 × 65.4 mm) ( SAM C15788 View Materials ) , 1 male (105.6 × 48.1 mm) ( SAM C15789 View Materials ) , 1 male (119.1 × 52.0 mm) ( SAM C15786 View Materials ), Darwin area , Northern Territory ; 1 male (81.1 × 36.6 mm) ( QM-W2205 ), trawled, SE of Wellesby Island, Gulf of Carpentaria , NW Queensland, 16°26'S 139°22'E GoogleMaps ; 1 male (54.4 × 25.5 mm) ( QM-W2865 ), trawl, Gulf of Carpentaria, off Karumba , NW Queensland, 17°29'S 140°50'E, coll. B. Campbell, 1966 GoogleMaps ; 1 female (138.8 × 66.7 mm, one lateral tooth chipped), 1 male (134.4 × 65.6 mm, one lateral tooth chipped) ( QM-W20688 ), 0.5 m, netted over mud and rubble, Karumba Point , NW Queensland, 17°28'05"S 140°49'04"E, coll. J. W. Short, 23 Jun.1995 GoogleMaps ; 1 male (27.7 × 13.3 mm) ( QM-W27092 ), SW coast Sweers Island , Gulf of Carpentaria, Queensland, 17°06'S 139°37'E, coll. P. Davie, 22 Nov.2002 GoogleMaps ; 1 female (74.4 × 35.5 mm, one lateral tooth chipped) ( QM-W8903 ), Norman River, Gulf of Carpentaria , Australia, coll. CSIRO ; 1 female (57.7 × 28.8 mm, one lateral tooth broken off) ( QM-W8904 ), Bynoe River , NW Queensland, 17°32'S 140°43'E, coll. CSIRO GoogleMaps ; 1 male (90.3 × 38.0 mm) ( QM-W12470 ), Torres Strait , northern Queensland, 10°02'S 142°31'E, coll. Queensland Fisheries Service, 13 m, 21 Apr.1974 GoogleMaps ; 1 male (55.4 × 25.6 mm) ( QM-W12434 ), Darnley Island , northern Queensland, 9°35'S 143°46'E, coll. Tosh GoogleMaps ; 1 male (55.4 × 25.6 mm) ( QM-W12434 ) , 4 females (66.6 × 28.8 mm, 61.1 × 26.6 mm, 54.4 × 23.3 mm, 57.7 × 25.5 mm), 2 males (58.9 × 25.5 mm, 49.9 × 22.2 mm) ( QM-W12430 ), Cape York ; 1 male (62.2 × 26.6 mm) ( QM-W6428 ), Quintell Beach, Iron Ra. , northern Queensland, 12°50'00"S 143°20'00"E, mangroves, coll. M. J. Bishop, Jul.1976 GoogleMaps ; 1 male (51.1 × 23.4 mm) ( QM-W9920 ), 70 km East Coen, northern Queensland, Australia , 13°55'04"S 143°48'06"E, 21.9 m, coll. Queensland Fisheries Service, Sep.1979 GoogleMaps ; 1 male (108.8 × 50.0 mm) ( QM-W9915 ), 40 km west Cape Melville , northern Queensland, 14°10'04"S 144°9'04"E, coll. Queensland Fisheries Service, 22 m, Sep.1979 GoogleMaps ; 1 female (122.2 × 51.1 mm) ( QM-W18142 ), Starcke R, northern Queensland, 14°47'08"S 144°59'09"E, netted, mid-estuary, sandy mud bottom, salinity 35 ppt, 0.3 m, coll. P. Davie & J. W. Short, 10 Nov.1992 GoogleMaps ; 1 male (95.6 × 39.8 mm) ( QM-W18215 ), beach S of Starcke R mouth, northern Queensland, 14°47'09"S 145°01'03"E, netted, 1m, gravel/mud, seagrass salinity 35 ppt, coll. P. Davie & J. W. Short, 13 Nov.1992 GoogleMaps ; 1 male (52.2 × 23.3 mm) ( QM-W6085 ), 13 miles due east of Oyster Reef , 17 miles NE Green Island, Queensland, 16°39'S 146°11'E, 73.2 m, coll. L. R. G. Cannon, 21 Feb.1979 GoogleMaps ; 2 females (73.3 × 32.2 mm, 45.5 × 21.1 mm, one anterolateral tooth chipped), 1 male (37.8 × 19.8 mm, one anterolateral tooth missing) ( QM-W2675 ), Machan’s Beach , NE Queensland, 16°51'S 145°45'E, 26 Dec.1960 GoogleMaps ; 3 males (67.5 × 28.8 mm, 57.7 × 25.5 mm, 63.3 × 27.7 mm) ( QM-W12776 ), SE end of Hinchinbrook Is., NE Queensland, 18°27'5"S 146°22'7"E, trawled, coll. C. Jones, Queensland Fisheries Service, 17 Mar.1985 GoogleMaps ; 2 males (68.8 × 29.7 mm, 41.3 × 20.01 mm) ( QM-W15209 ), Gladstone , Queensland, 23°51'S 151°16'E, coll. P. Saenger, Queensland Electricity Commision Survey, 1974–1983 GoogleMaps ; 1 male (15.5 × 6.7 mm) ( QM-W2705 ), Burnett R. Heads , SE Queensland, 24°26'S 152°25'E, coll. N. Milward, 20 Apr.1966 GoogleMaps ; 1 male (20.0 × 9.9 mm) ( QM-W2674 ), Burnett River Heads , SE Queensland, 24°46'S 152°25'E, coll. N. Milward, 26 Aug.1965 GoogleMaps ; 1 female (44.4 × 20.0 mm) ( QM-W5344 ), south of Urangan Boat Harbour, Hervey Bay , SE Queensland, 25°18'S 152°55'E, estuarine, coll. P. Davie & R. Timmins, 23 Jul.1975 GoogleMaps ; 1 female (47.6 × 21.1 mm), 3 males (41.1 × 18.8 mm, 40.0 x 18.8 mm, 39.9 × 18.8 mm) ( QM-W5398 ), mud flats S. of Urangan Boat Harbour, Hervey Bay , SE Queensland, 25°18'S 152°55'E, coll. P. Davie, 23 Jul.1975 GoogleMaps ; 1 female (71.1 × 20.0 mm) ( QM-W9461 ), Susan River , SE Queensland, 25°26'S 152°56'E, coll. A. Ellis, 31 Oct.1970 GoogleMaps ; 2 males (22.2 × 10.0 mm, 21.1 × 10.0 mm), 2 females (36.5 × 15.6 mm, 30.0 × 12.3 mm) ( QM-W9470 ), Susan River , SE Queensland, 25°26'S 152°56'E, coll. A. Ellis, 25 Dec.1970 GoogleMaps ; 1 female (108.8 × 43.4 mm), 1 male (63.6 × 41.1 mm, lateral teeth missing, measurement taken from the 8th anterolateral tooth) ( QM-W3393 ), 5–6 miles E. Pt. Cartwright Light , SE Queensland, 26°41'S 153°15'E, 35 m ,, coll. F. Wallace, 6 Mar.1970 GoogleMaps ; 1 juv. male (52.2 × 24.4) ( QM-W1060 ), east flat, Green Island , SE Queensland, 27°26'00"S 153°14'00"E GoogleMaps ; 2 females (129.9 × 55.5 mm, 117.6 × 53.3 mm), 3 males (117.6 × 53.3 mm, 111.1 × 50.0 mm, 122.1 × 58.8 mm) ( QM-W2492 ), off St. Helena Island , SE Queensland, 27°24'S 153°14'E, coll. L. Wale, University of Queensland, 28 Jul.1966 GoogleMaps , trawled; 2 females (82.3 × 37.7 mm, 63.4 × 31.0 mm), 4 males (32.2 × 15.5 mm, 29.9 × 14.5 mm, 35.5 × 17.7 mm, 35.5 × 17.7 mm) ( QM-W26681 ), Scarborough Spit, Moreton Bay , SE Queensland, 27°11'05"S 153°7'00"E, 0.5 m, netted over sand and shell substrate, coll. J. Johnson, 21 Jan.2003 GoogleMaps ; 2 males (52.3 × 22.2 mm, 42.2 × 19.9 mm) ( QM-W797 ), Moreton Bay , SE Queensland, 27°25'S 153°20'E GoogleMaps ; 1 male (17.7 × 8.8 mm) ( QM- W2474 ), beach at Sandgate, Moreton Bay , SE Queensland, 27°20'S 153°04'E, 9 Oct.1962 GoogleMaps ; 1 male (42.2 × 18.8 mm) ( QM-W5232 ), Serpentine Creek , SE Queensland, 27°23'S 153°5'E, coll. B. Campbell et al., 12 Oct 1972 GoogleMaps ; 5 males (25.6 × 11.1 mm, 12.3 × 6.6 mm, 16.6 × 8.8 mm, 21.2 × 10.0 mm, 28.8 x 12.4 mm) ( QM- W12005 View Materials ), Serpentine Creek, Cribb Island, Nudgee Beach , SE Queensland, 27°21'S 153°7'E, coll. I. Stejskal, 1984 GoogleMaps ; 1 male (19.9 × 10.0 mm) ( QM-W8726 ), mouth of Brisbane R., SE Queensland, 27°24'S 153°10'E, 1 m, coll. Zoology Department, University of Queensland, 19 Sep.1975 GoogleMaps ; 1 male (18.8 × 9.9 mm) ( QM-W1203 ), mud flat, Myora , SE Queensland, 27°29'S 153°25'E, coll. University Science Students Association GoogleMaps ; 1 male (55.4 × 24.4 mm), 1 female (60.0 × 26.7 mm) ( QM-W12432 ), Sandgate , SE Queensland, 27°20'S 153°4'E, coll. R. Hamlyn-Harris GoogleMaps ; 1 juv. female (22.2 × 10.0 mm) ( QM-W836 ), Goat I., SE Queensland, 27°31'S 153°23'E, 1 Jan.1938 GoogleMaps ; 1 female (107.7 × 48.8) ( QM-W19588 ), Moreton Bay , SE Queensland, 27°17'S 153°15'E, trawled, coll. S. Cook, 3 Jun.1993 GoogleMaps ; 2 males (15.6 × 8.7; 15.5 × 7.7), 1 female (17.7 × 8.8) ( QM-W7231 ), Deception Bay, Moreton Bay , SE Queensland, 27°10'S 153°5'E, coll. CSIRO, 6 Nov.1972 GoogleMaps ; 3 males (15.5 × 7.7; 21.1 × 9.9; 15.5 × 7.7), 1 female (18.8 × 8.8 mm) ( QM-W7217 ), Deception Bay, Moreton Bay , SE Queensland, 27°10'05"S 153°30'00"E, coll. CSIRO, 6 Nov.1972 GoogleMaps ; 1 male (152.1 × 74.4 mm) ( QM-W2515 ), Moreton Bay, near Mud Island , SE Queensland, 27°20'S 153°15'E, trawled, 20 Oct.1966 GoogleMaps ; 1 male (22.2 × 10.0 mm) ( QM-W2356 ), South Dunwich , SE Queensland, 27°30'S 153°24'E, coll. F. C. Vohra GoogleMaps ; 1 male (144.4 × 68.7 mm) ( QM-W1931 ), Lake Macquarie , New South Wales, 32°59'S 151°38'E, 26 Sep.1953 GoogleMaps ; 1 male (143.2 × 65.5 mm) ( QM-W1933 ), Lake Macquarie , New South Wales, 32°59'S 151°38'E, 26 Sep.1953 GoogleMaps ; 1 female (136.5 × 62.2 mm) ( QM- W1932 ), Lake Macquarie , New South Wales, 32°59'S 151°38'E, 26 Sep.1953 GoogleMaps ; 3 males (largest 150.9 × 73.4 mm), 2 females (larger 135.6 × 67.5 mm) ( ZRC 2007.0232 View Materials ), Nelson Bay, Port Stephen , New South Wales ; 6 juv. males (largest 14.6 × 31.4 mm) ( ZRC 2007.0236 View Materials ), Sandringham, Botany Bay, on Zostera flats, Sydney , New South Wales, netted at 0.5 m, coll. S. Ahyong, 4 Jul.2003 ; 3 males (largest 134.7 × 65.1 mm), 3 females (largest 132.4 × 65.2 mm) ( ZRC 2007.0212 View Materials ), Spencer Gulf , South Australia, coll. S. Ahyong ; 3 male, 1 female (183.7 × 86.4 mm) ( ZRC 2007.0227 View Materials ), Brighton Beach, Gulf St. Vincent, South Australia, coll. S. Ahyong & M. Middleton, Dec.2003 ; 1 female (159.1 × 76.2 mm) ( ZRC 2007.0228 View Materials ), Whyalla, Spencer Gulf , South Australia, trapped 1-2m, coll. M & L. Middleton, Dec.2003 ; 1 male (133.0 × 66.0 mm) ( ZRC 2007.0229 View Materials ), Spencer Gulf vicinity, South Australia, coll. S. Ahyong. NEW CALEDONIA : 2 males (larger 133.0 × 75.6 mm), 1 female (97.1 × 54.6 mm) ( MNHN), Navlie Vauban Croisiere St. Vincent St 4, 14 m (22°05'06"S 166°04'05"E), 24 Apr.1985 GoogleMaps ; 1 male (124.0 × 70.7 mm), 1 female (110.5 × 62.7 mm) ( MNHN), ORSTOM Vauban, Chalutage 12, 4– 6 m 21°56'06"S 166°02'02"E, 30 Apr.1985 GoogleMaps ; Banc Gail, Prof 30m , 1 female (106.4 × 60.8 mm) ( MNHN), coll. Tivard, 30 Jul.1986 ; 1 female (101.0 × 58.0 mm) ( MNHN), Baie de St Vincent, Chalutage 1, coll. M. Kulbichi, 20 Aug.1985 ; 1 female (132.5 × 88.0 mm) ( MNHN), Lagoon Nord- Ouest St. CP 1060, 12– 14m (20°14'03"S 164°15'04"E), coll. B. Richer de Forges, 5 May 1988 GoogleMaps ; 2 juv. males (larger 83.6 × 47.2 mm) ( MNHN), Bourake , St CP 2 from the “Alis”, coll. M. Kulbichi, 30 Jan.1989 ; 2 males (28.8 × 12.3 mm, 25.6 × 11.2 mm) ( QM- W19909 View Materials ), Dumbéa , coll. P. Davie, 7 Dec.1993 , mangroves.

Diagnosis. – Carapace width 2.0–2.3 times wider than long, however, on average, carapace width of P. armatus less elongated compared to other species, more quadrate in appearance. Median frontal teeth very sharp, spinous, conspicuous. Carapace regions relatively poorly indicated, branchial regions not markedly swollen, surface with coarser granulations compared with other species. Chelipeds in large males stout, more robust than other species, 3.5 times longer than wide (median ratio of 3.2). Anterior margin of cheliped merus usually with 4 (occassionally 5) spines (including extra enlarged spine proximally near joint). Ambulatory legs relatively stouter compared with P. pelagicus , ratio of 4 th pereiopod propodus length to width ranging from 2.9–3.7 (median 3.6). Natatorial paddle relativey broader, rounder compared with other three species ( Fig. 21D View Fig ). Sixth male abdominal somite relatively elongate, tapering ( Fig. 22D View Fig ). Base of G1 without round basal spur, or if present blunt, rounded ( Fig. 20D View Fig ). Colour pattern with spots tending to remain relatively discrete, though sometimes fusing into thin irregular short bands thinner than those on P. pelagicus . Female patterns similar to males but differs in colour compared with females of other three species ( Fig. 7D View Fig ). Maximum size of 200 mm carapace width ( Kailola et al., 1993).

Life colours ( Figs. 6D View Fig , 7D View Fig , 19 View Fig ). – Carapace colouration varies from dark blue and purple to green in males, brown in females. Banding patterns present on carapace present, but thinner and sparse in comparison to the other three species; posterior part of carapace ocellated, markings on carapace resemble thin reticulations, never as thick or as dense as markings on the others. Females with a background colour in varying shades of brown, but similar banding patterns to male. Within P. armatus , there appears to be regional variation in the colour of males around Australia, especially from South Australia in Spencer Gulf and Gulf St. Vincent, where males typically are brighter blue and exhibit less reticulation than those from other localities ( Fig. 19D View Fig ) (S. Ahyong, pers. comm.). They are otherwise indistinguishable morphologically and genetically.

Remarks. – Alphonse Milne-Edwards described Neptunus armatus in 1861 based on at least one juvenile male collected from Shark Bay, Western Australia, commenting that the shape of its frontal and anterolateral teeth seemed broader at the base than P. pelagicus to which it was otherwise similar. Portunus armatus was accepted as a valid species by both Miers (1884) and Henderson (1893), although Alcock (1899: 34) tentatively regarded it as a junior synonym of P. pelagicus . Following Alcock’s action, the species was essentially forgotten and not mentioned in recent Australian literature. In particular, it was overlooked by Stephenson & Cambell (1959) in their review of the Australian Portunus species , Stephenson (1972a), in his checklist of the Indo-West Pacific Portunidae, Jones (1994) , in her checklist of marine decapod crustaceans from Shark Bay (the type locality), and by Davie (2002), in his synopsis of the Australian fauna.

The confusion over the identity of P. armatus and subsequent lack of records in Australia may be attributed to the fact that the original description was based on a juvenile of only carapace length 15 mm (large adults are typically more than 150 mm), and the length of the last anterolateral spine is much longer than in adult specimens. Secondly, the accompanying illustration (reproduced in Fig. 17B View Fig ) differs from the lectotype and paralectotype specimens in at least two key features: 1) the posterolateral corner of the carapace is square in the illustration, but rounded in reality; and 2) the carapace proportions of the drawing are distorted so that it appears wider than the type specimen on which it was based. Henderson (1893) first commented that A. Milne-Edwards gave incorrect carapace dimensions, and that the length of the last anterolateral spine was inaccurately drawn. Photographs of a syntype ( NHM 1858.172 .115) ( Fig. 17A View Fig ) kindly provided by P. Clark ( NHM), leave us in no doubt that this is the specimen figured by A. Milne- Edwards (1861), and we here designate it as the lectotype. The general features, positions of the legs and chelipeds all match, although as already mentioned, the last anterolateral spine is exaggerated in the drawing, and the measurements originally given are different .

Stephenson (1968b) had access to a series of specimens collected from across the Indo-West Pacific and Australia, and concluded that perceived differences between samples from different localities may be attributed to regional clines or varieties. Indeed, there does appear to be some regional colour variation between P. armatus specimens collected from localities around Australia. In particular, the colour of specimens collected from Spencer Gulf/Vincent Gulf in South Australia deviate the most from “typical” P. armatus collected in other localities ( Fig. 9D View Fig ). However, the fundamental shape and positioning of the underlying patterning is retained, and females are consistently the same as elsewhere. It was also noted by Bryar & Adams (1999) that allozyme data provide no evidence that the marked colour and pattern variations in P. armatus from different regions around Australia are due to the presence of cryptic species or subspecies. Rather, they speculated that variation in pigmentation is probably due to phenotypic plasticity as reported by Meagher (1971) and Bryars (unpublished data) from laboratory held individuals.

Initially, the extreme length of the last anterolateral spine in the lectotype cast some doubt as to whether it was conspecific with the “ P. pelagicus ”-like species occurring in Australia, but a comparison with juvenile specimens collected from both the type locality in Shark Bay , Western Australia, and from New South Wales indicates that spine length is significantly variable, and that longer spined juveniles similar to the lectotype do occur, and seem to be more common in Western Australia ( Fig. 18 View Fig ) .

Other specimens identified by Henderson (1893) as P. armatus from outside Australian waters have also been re-examined. Five small specimens (the largest being 30.5 mm wide) from Pamban, Rameswaran, India, are actually juvenile P. reticulatus ; and similarly, specimens identified as P. armatus from Chefoo, China, belong to P. trituberculatus .

While we are sufficiently certain that the specimen here designated as lectotype ( NHM 1858.172.115) is the same as that described and illustrated by A. Milne-Edwards (1861), a second specimen of P. armatus with the same register number ( NHM 1858.172 ) but a different specimen number (114) was uncovered by P. Clark. As these two specimens were listed together as a single lot in the accession book, it is likely that A. Milne-Edwards examined both specimens. However, he did not indicate how many specimens he had seen. As no holotype was selected, we here recognise both specimens as syntypes and designate a lectotype and paralectotype as earlier indicated .

Portunus armatus appears to be the largest of the four species in the P. pelagicus -complex, with the biggest specimen recorded attaining 200 mm in carapace width ( Kailola et al., 1993). It is of significant economic importance in Australian fisheries and subject to stringent catch quotas and size restrictions. As such, its population dynamics and biology in Australian waters are relatively well studied (see Shields, 1992; Sumpton et al., 1994; Weng, 1987, 1992; Xiao & Kumar, 2004).

Habitat. – Lives in a variety of inshore and continental shelf waters from low intertidal to 50 m depth; prefers flatter sandy to muddy bottoms with algal and seagrass communities ( Edgar, 1990; Williams, 1982). Juveniles are common near low water mark on intertidal flats; adults can also sometimes be found in shallow water near low tide mark, but mostly crabs move into deeper water as they age in response to changes in water temperature and inshore salinity ( Potter et al., 1983). At least in Moreton Bay, ovigerous crabs move into deeper more oceanic water for spawning ( Potter et al., 1987).

Distribution. – In Australia from Cape Naturaliste, Western Australia, around northern Australia south to about the southern border of New South Wales; also found in the warmer waters of the South Australian Gulfs, as far south as Barker Inlet in Gulf St Vincent ( Kailola et al., 1993). Lord Howe Island; Arafura Sea off southern Papua; occasional records from the North Island of New Zealand, but apparently not able to form a sustainable population ( Dell, 1964). In New Caledonia, they are present but rare within the shallow lagoon fringing the island. P. armatus has no commercial value in New Caledonia, and is more often regarded as a pest as they tend to congregate around floating fish holding pens within the lagoon and damage nets as well as fish stocks kept within. With the decline in fish holding aquaculture in New Caledonia, P. armatus density within the lagoon has also diminished (B. Richer de Forges, pers. comm.).

WAM

Western Australian Museum

SAM

South African Museum

MNHN

Museum National d'Histoire Naturelle

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Decapoda

Family

Portunidae

Genus

Portunus

Loc

Portunus armatus (A. Milne-Edwards, 1861 )

Lai, Joelle C. Y., Ng, Peter K. L. & Davie, Peter J. F. 2010
2010
Loc

Portunus (Portunus) armatus

Ng, P 2008: 152
2008
Loc

Portunus pelagicus

Davie, P 2005: 157
Rice, T 1999: 222
Davie, P 1998: 100
Poupin, J 1996: 32
Stephenson, W 1976: 18
Heath, J 1973: 2
Stephenson, W 1972: 15
Stephenson, W 1972: 137
Turkay, M 1971: 123
McNeill, F 1968: 54
Stephenson, W 1968: 84
Hale, H 1927: 149
1927
Loc

Neptunus pelagicus

Milne-Edwards, A 1873: 156
1873
Loc

Neptunus armatus A. Milne-Edwards, 1861: 322

Milne-Edwards, A 1861: 322
1861