Portunus segnis ( Forskål, 1775 )

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: 215-218

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

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scientific name

Portunus segnis ( Forskål, 1775 )
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Portunus segnis ( Forskål, 1775)  

( Figs. 6B View Fig , 7B View Fig , 11 View Fig , 12 View Fig , 13 View Fig , 14 View Fig , 20B View Fig , 21B View Fig , 22B View Fig , 23B, 23F View Fig , 24B View Fig )

Cancer segnis Forskål, 1775: 18   , 91.

Cancer pelagicus Forskål, 1775: 89   .

Crabes-nageurs Savigny, 1826: Pl. 3, Fig. 1. 1–4 View Fig View Fig View Fig View Fig .

Portunus mauritianus Ward, 1942: 79   , Pl. 5 Fig. 5 View Fig .

Portunus trituberculatus   – Stephenson & Rees, 1967b: 51–53 (in part, material from the Red Sea) [not P. trituberculatus Miers, 1876   ].

Lupa pelagica   – Heller, 1861: 355 (part); Barnard, 1950: 152–154 Fig. 27b; Fourmanoir, 1954: 7, Fig. 7 View Fig .

Neptunus (Neptunus) pelagicus   – Parisi, 1916: 171 (part); Stephensen, 1946: 124, 125, Fig. 26E; Hashmi, 1963a: 239; Hashmi, 1963b: 115, 117, 118.

Portunus (Portunus) pelagicus   – Audouin, 1826: 83; 1827: 261; Tirmizi & Kazmi, 1983: 369; Ng et al., 2008: 152.

Neptunus pelagicus   – Hoffmann, 1874: 7, 8; Paul’son 1875: 61; De Man, 1888: 328; Nobili, 1906: 190; Klunzinger, 1913: 336 Pl. 7: Fig. 17 View Fig ; Kohli, 1921: 85; Monod, 1930: 138,140, Fig. 6 View Fig ; 1938: 116; Gruvel, 1936: 50, 51, 71, 86, 94, 192, 195, 207, 215; Pretzmann, 1971: 471; Chandy, 1973: 402; Khan, 1975: 377 (list), 379–381, 390 (key), Fig. 2 View Fig , Pl. 1.

Portunus pelagicus   – Crosnier, 1962: 43–45, Figs. 58, 61, 67; Guinot, 1962: 10; Heath, 1973: 2 (key), 13, Fig. 4b View Fig ; Pretzmann, 1971: 47; Ramadan & Dowidar, 1972: 132; Khan & Ahmed, 1975: 77; Mustaquim & Rabbani, 1976: 163; Basson et al., 1977: 224, 227, 231, 235, 250, 256; Kensley, 1981: 42 (list); Titgen, 1982: 118–120, 250 (list); Jones, 1986: 161, Pl. 47; Tirmizi & Kazmi, 1996: 18-21; Bahmani, 1997: 2, 6, 8, 9, 12; Hornby, 1997: 75; Carpenter et al., 1997: 38; Apel & Spiridonov, 1998: 279 (key), 300–303, Pls. 10, 11; Neumann & Spiridonov, 1999: 21; Vannini & Innocenti, 2000: 266, Figs. 18 View Fig , 23 View Fig , 76; Galil et al., 2002: 114; Corsini-Foka et al., 2004: 83.

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

Portunus pelagicus   or P. segnis   – Guinot & Cleva, 2009: 70, Pl. 3, Fig. 1 View Fig .

Material examined. – Neotype of Cancer segnis Forskål, 1775   (here designated); 1 male ( SMF 3679) (144.4 × 70.1 mm), Red Sea, Egyptian coast, probably southern Gulf of Suez, coll. Dr E. Bannwarth, 1912. Others: BAHRAIN: 1 male (113.1 × 49.8 mm), 1 female (103.1 × 46.0 mm) ( SMF 24424 View Materials ), from fisherman’s nets (BRN-02). ISRAEL: 3 males (largest 147.2 × 66.8 mm), 1 female (143.3 × 62 mm) ( ZRC 2007.225), off Ashjod, trawled by trawler MOTI, 12–14 fathoms, coll. B. Galil, 5 Dec.2003; 4 males (largest 141.3 × 66.9 mm), 9 females (154.8 × 72.5 mm) ( ZRC 2007.226) off Haifa, coll. B. Galil, 2005; 1 male (134.5 × 62.6mm) ( ZRC 2007.226), Mediterranean Coast. KENYA: 1 male ( MZUF C898), Gazi, coll. M. Vannini, Dec.1997. KUWAIT: 1 male (56.8 × 25.2 mm) ( NHM 1978.200), Khiran, Kuwait coast, coll. M. N. Mashmoom. MADAGASCAR: 8 males (largest 140.1 × 62.3 mm), 5 females (largest 153.2 × 69.4 mm), 6 juvs. ( ZRC 2007.220), Belaza Tulear, coll. H. H. Tan, Jan.2004; 1 male (90.9 × 40.8 mm), 1 female (116.2 × 52.3 mm) ( RMNH 47694), market at Morondava, west coast, coll. C. C. J. Jongkino, 11 Jan.1997; 1 juv. male (CL 24.37 mm) ( MNHN 844), Nosy Be, coll. A. Crosnier, 2 May 1961. MEDITERRANEAN SEA: 1 male (109.1 × 50.9 mm), 1 female (99.4 × 43.9 mm) ( MNHN B12284 View Materials ), Gulf of Terente, coll. Perenzan, 1969. MOZAMBIQUE: 4 juv. males (largest 37.2 × 21.7 mm), 3 juv. females (largest 45.4 × 26.7 mm) ( NHM 1951.9.13.416), Inyack Bay, Inhaca, Delagoa Bay (present day Maputo Bay), coll. O. S. Tattersall; 2 males, 1 female (126.6 × 60.00 mm) ( ZRC 2007.230), Maputo Bay, coll. P. Clark, 2004. PAKISTAN: 5 males (largest 156.2 × 74.2 mm), 22 females ( ZRC 2006.70), Karachi, coll. Q. B. Kazmi, Sep.2005; 1 juv. male (37.0 × 21.6 mm) ( SMF 21626 View Materials ), Korung Creek, Indus Delta, Sindh, coll. G. Pillen. PERSIAN GULF: 1 female (77.6 × 35.6 mm) ( NHM 88.25), coll. Kurachee Museum. RED SEA; 4 males ( SMF 10693 View Materials ) (94.9 × 43.1 to 115.5 × 55.1 mm), Jeddah Fish Market, Saudi Arabia, Red Sea, W. John, 20 Aug.1982; 1 male (114.5 × 53.4 mm) ( MNHN B6032), coll. 1929; 1 juv. female (70.2 × 39.3 mm) ( NHM), El Tor Presed, coll. Major Macdonald, 4 Sep.1966; 2 females (larger 72.2 × 40.4 mm) ( NHM), Gulf of Ilat, Aryab, coll. F. Day. SAUDI ARABIA: 5 male, 1 female (48.2 × 21.6 mm) ( NHM), Jedda, coll. A. C. Trott; 1 female (106.9 × 62.1 mm) ( SMF 24427 View Materials ), Jubail Marine Wildlife Sanctuary Al-Jubayl, W. Qurma Island, PTL-01 (27º07.090'N 49º27.300'E) sand/mud bottom, coll. M. Apel, 4 Dec.1991; 2 females (larger 132.7 × 60.6 mm) ( SMF 24430 View Materials ), Eastern, N. Jubail (27°25.410'N 049°16.010'E), sandy bottom, coll. M. Apel, 26 Nov.1991; 2 males (larger 56.4 × 25.7 mm), 2 females (larger 80.5 × 35.0 mm) ( SMF 24417 View Materials ), Eastern, Ras Az-Zawr (27°26.000'N 49°17.000'E) sublittoral sand flats, coll. M. Apel, 17 May 1995; 1 juv. male (31.7 × 15.0 mm), 1 juv. female (32.4 × 15.3 mm) ( SMF 24418 View Materials ), Eastern Ras Az-Zawr (27°26.000'N 49°17.000'E), beachrocks and sand, coll. M. Apel, 17 May 1995; 1 male (130.7 × 59.5 mm) ( SMF 24428 View Materials ), Eastern Jubail Marine Wildlife Sanctuary, N. Al-Jubayl, W. Jinna Island, PTL-04 (27°21.490'N 49°14.200'E) on rock and sand, coll. M. Apel, 28 Nov.1991; 1 male (95.9 × 43.0 mm) ( SMF 24429 View Materials ), Eastern Jubail Marine Wildlife Sanctuary, N. Al-Jubail, SW bank of Dauhat al Musallamiya, PTL-07 (27°23.330'N 49°10.150'E) on rock and mud, coll. M. Apel, 10 Dec.1991. SOMALIA: 1 male (117.2 × 51.9 mm), 1 female ( MZUF C811), Gresira, coll. M Vannini, Nov.-Dec.1976; 1 male (76.9 × 34.4 mm) ( MZUF C2672), 2 males (larger 127.8 × 58.3 mm), 4 females (135.8 × 61.2 mm) ( MZUF C2673), Sar Vaule, coll. M. Vannini, 1976; 1 juv. male (38.9 × 18 mm), 1 male (113.8 × 51.7 mm) ( NHM 1950.8.851), Zeilah, coll. A. Fraser-Bronner; 1 male (114.5 × 53.5 mm) ( MZUF C890), Mida Creek, Kenya, coll. M. Vannini, 1991; 2 females (94.1 × 43.7; 122.4 × 53.9 (ovig.) mm), 2 males (68.1 × 33.1; 84.3 × 38.2 mm) ( MZUF C890), Mtwapa, Mombasa, Kenya, coll. M. Vannini, Nov.–Dec.1993. SOUTH AFRICA: 1 male ( NHM 1917.6.19.37), Durban Bay, Natal, from Durban Bay Natal Government Museum, coll. F. Toppin, Mar.1905; 1 male (168.8 × 75.8mm) ( ZRC), coll. Institute of Aquatic Biodiversity, South Africa, Nov.2006. SUDAN: 1 male (newly moulted) ( SMF 24487 View Materials ), Küsta ca. 8 km Port Sudan, SAN-53, in Avicennia marina   mangrove, coll. M. Apel, 23 Mar.1991. GULF OF SUEZ: 2 females (larger 130.5 × 60.1 mm) ( MNHN B6031), from SS Al Sayad, Station II, 1928. SYRIA: 1 male (144.7 × 68.0 mm), 2 females (larger 158.4 × 75.4 mm) ( SMF 8768), fish market, Latakia, coll. R. Kinzelbach, 31 Aug.1978. UNITED ARAB EMIRATES: 2 males (larger 119.9 × 54.4 mm), 3 females (largest 125.7 × 57.9 mm) ( ZRC 2007.224), Abu Dhabi, market facing Oman coast, coll. L. W. H. Tan, 26 Mar.2004, 2 juv. males (larger 48.3 × 21.8 mm) ( NHM 1999.68- 69), Trucial Coast, Abu Dhabi, coll. D. J. J. Kinsman, Imperial College; 1 juv. male (28.4 × 13.3 mm) ( NHM 1966.10.4.23), Khor al Bazam PS/34, Trucial Coast, Abu Dhabi, coll. Imperial College; 1 damaged female (58.0 × 26.5 mm) ( NHM 1966.10.4.22), Khor al Bazam, PG/B/449, Trucial Coast Abu Dhab, coll. Imperial College; 1 male ( SMF 24422 View Materials ), mangroves of Umm al Qaiwai, UAE 95-29 (25°35.000'N 55°34.000'E), 0-1m around small islands, Khor al Beidah, coll. M. Apel, 9 Jul.1995. OMAN: 2 females (larger 38.4 × 86.1 mm), 2 males (larger 37.7 × 83.2 mm) ( UF 7745), south end of Bar al Hikman peninsula, silty pebbly sand spit, coll. U. Bonito et al., 24 Jan.2005. MAURITIUS: 1 male (carapace width 170.0 mm, side of carapace damaged) ( MPL MAU-231) (damaged) (holotype of Portunus mauritianus Ward, 1942   ).

Type material. – The holotype of Forskål (1775) from Djedah (present day: Jeddah) in the Red Sea is lost, and a neotype for Cancer segnis   is thus necessary to stabilise the nomenclature of this species   .

We have selected a specimen collected from the original locality, a male ( SMF 3679 View Materials ) (144.4 × 70.1 mm), as the neotype   .

Diagnosis. – Carapace width 2.2–2.3 times wider than long, median frontal teeth minute or obsolete, usually inconspicuous, appearing confluent or with wide gap between lateral median teeth, except sometimes in larger individuals (carapace width> 140 mm). Compared with adult male P. pelagicus   , carapace regions relatively poorly defined, branchial regions not as swollen compared with P. pelagicus   . Chelipeds narrow, elongated, merus length of adult males maximum 4.5 times longer than wide; most specimens with shorter, stouter chelipeds than P. pelagicus   ; anterior margin of merus of cheliped usually with 3 spines. Ambulatory legs relatively more elongated, slender, merus of 4 th pereiopod 3.3–4.4 (median 3.6) longer than wide ( Fig. 21B View Fig ). Natatorial paddle elongate oval, obtusely angled distally, similar to P. pelagicus   . Sixth male abdominal somite relatively shorter, less tapering ( Fig. 22B View Fig ). Base of G1 with slight basal spur ( Fig. 20B View Fig ). Largest specimen known is a female from Syria, 158.4 × 75.4 mm) (SMF 8768).

Life colours ( Figs. 6B View Fig , 7B View Fig , 14 View Fig ). – Males with dark olive green blue carapace with many pale white spots on surface particularly posteriorly and anterolaterally; spots do not tend to merge to form reticulating bands, however, such banding if present is typically thinner than in P. pelagicus   . Females similar in pattern to male except that tips of chelipeds are red tinged with a brownish red instead of blue tinged with deep rust red.

by Forskål with the Latin name “ segnis   ”. The presence of a white tip at the apex of the cheliped (Chelae viridi-caeruleae, apice albae), and the presence of a blue green spine with a red tip near the carpus (ad basin juxta carpum superne spina valida, conica, caerulea apice ferruginea) is peculiar — the P. pelagicus   -complex conversely have red tips to the chelipeds and white tipped carpal spines. However, Forskål’s description of a dark green blue carapace with white cloud like markings (color superne obscure-viridis, nebulosus) does not fit any other portunid known from the Arabian Gulf other than P. pelagicus   sensu lato (Apel & Spiridonov, 1998). This description matches the illustration of “Crabes-nageurs” presented in Savigny (1826: Pl. 3, Fig. 1. 1–4 View Fig View Fig View Fig View Fig ) (reproduced as Fig. 12 View Fig , from Guinot & Cleva, 2009: 70, Pl. 1, Fig. 3 View Fig ) and may explain some of his observations. The name “ Cancer segnis   ” has not been used or discussed since its description. Unfortunately, Forskål’s voyage ended with his premature death and the type specimen which ought to have been sent to Denmark was never located (for an historical account of the Danish expedition to “Arabia Felix” see Nielsen, 1993; Wolff, 1999). Interestingly, Forskål (1775) referred to C. pelagicus   on page 89 before describing the new species, C. Remarks. – Forskål (1775) described Cancer segnis   from material collected from Jeddah, on the Red Sea coast of Saudi Arabia. His description is as follows: “ Cancer segnis   ; brachyurus; thoracae laevi, utroque latere novem-dentato; fronte quatuor-dentata. Descr. Transverse-ovalis: latitudine spithamae, sed longitudine inferior. Color superne obscureviridis, nebulosus; subtus albidus. Antennae setaceae, nigrae, breves. In fronte spinae 4, inter oculos erectae, obtusiusculae: sub quovis oculo una validior. Oculorum pedicelli teretes, virides, oculi hemisphaerici; nitentes, obscuro-rubri, maculis albis: profunde inserti. Chelae viridi-caeruleae, apice albae: in forficis latere interiore una series callorum in singulo digito; in chela superne post basin pollicis spinae duae, contiguae, antrorsum spectantes: ad basin juxta carpum superne spina valida, conica, caerulea apice ferruginea, Praeterea nullae in chelis spinae; fed duae in carpis extrorsum, una introrsum, longior, fortior, Femora depressa, ob-cuneata, Secundum tertium par pedum subteres, versus apicem compressum, police nullo, leave, digito subulato. Quartum par longe crassius, articulis duobus postremis compressissimis, membranaceis, dilatatis, ovatis, margine ciliates. Cauda lata, albida, fusco-rivulata. In Mari rubro. Tarde procedit in aqua.”

Forskål’s description is relatively detailed for its time, and generally fits P. pelagicu   s sensu lato. While there are some discrepancies, there does not seem to be any other likely candidate amongst the Red Sea fauna. Interestingly, most live portunids are active and aggressive, not “slow” as implied segnis   on page 91. As there is marked sexual dimorphism in the species, perhaps like Herbst, Forskål (1775) had mistaken males and females as different species (see discussion for P. reticulatus   ), and inadvertently established C. segnis   for one sex. Another consideration is that his account is published posthumously and was most likely based on his field notes. Thus, it may also be possible that errors in description could have been the result of wrong interpretations of his notes or errors in typesetting. In any case, P. segnis   is restricted to the West Indian Ocean (Red Sea and African coast) and differs from P. pelagicus   of eastern Asia both morphologically and genetically.

Portunus mauritianus Ward, 1942   , was described from Mauritius, southwest Indian Ocean. From Ward’s (1942) description, it is apparent that what he conceived to be the true “ P. pelagicus   ” was the Australian species, P. armatus   . Consequently, he was correct in recognising the Mauritius material as a separate species. Portunus armatus   has more clearly defined carapace granulation, sharper teeth and spines on the frontal and anterior margins, a differently shaped natatorial paddle, as well as four spines on the anterior margin of the merus of the cheliped versus three in P. mauritianus   . The holotype of P. mauritianus   is housed in the Mauritius Institute, but the specimen is badly damaged and all trace of colour patterning has been lost ( Fig. 11 View Fig ). Examination of photographs of the holotype from different angles shows it to be distinct from P. armatus   , but its poor condition and broken carapace make it difficult to clearly separate it from P. pelagicus   and P. reticulatus   . Unlike typical P. segnis   , the holotype has two distinct median teeth, but the specimen is large and larger specimens of P. segnis   are also known to have prominent median teeth. Attempts were made to collect topotypes of P. mauritianus   for further morphological and genetic study. However, the species is apparently uncommon in Mauritius (C. Michel, pers. comm.) and no specimens were collected. Anecdotal evidence also suggests that at least some P. pelagicus   sensu lato sold in Mauritius may be imported from Mozambique or Madagascar although this could not be verified with actual collected material in the present study. Nevertheless, from the recent photographs we have of the holotype ( Fig. 11 View Fig ) and Ward’s figures of the chelipeds and gross morphology, along with the fact that only P. segnis   is otherwise known from the western Indian Ocean, it is likely that P. mauritianus   is a subjective junior synonym of P. segnis   .

Stephenson & Rees (1967b) recorded one male and three female specimens of P. trituberculatus   from the Red Sea, but Stephenson (1976) later clarified that this was a mistake and that the species attributed to P. trituberculatus   was in fact P. pelagicus   (= P. segnis   in present study). The figure by Stephenson & Rees (1967b: Fig.17a, b View Fig ) compares “ P. trituberculatus   ” from the Red Sea with P. pelagicus   from the Philippines. It is possible that they used the absence of median frontal teeth in the Red Sea material to distinguish between the two species. When viewed dorsally, the lack of median frontal teeth coupled with the projection of the epistomial spine along the underside of the frontal margin gives the illusion of three teeth along the frontal margin and this was presumably the reason for their misidentification as P. trituberculatus   .

Habitat. – Under rocks and in rock pools, on sandy or muddy substrate, intertidal to 55 m ( Galil et al., 2002). Common in fish landings in Pakistan (Tirmizi & Kazmi, 1996).

Distribution. – Western Indian Ocean, from Pakistan westwards to the Arabian Gulf, and extending to the east coast of South Africa, Mozambique, Madagascar and Mauritius. It has also entered eastern Mediterranean Sea, as a Lessepsian migrant through the Suez Canal ( Ekman, 1967; Ozcan et al., 2005; Yokes et al., 2007) and become established as far north as the northern Tyrrhenian Sea ( Crocetta, 2006).

SMF

Forschungsinstitut und Natur-Museum Senckenberg

ZRC

Zoological Reference Collection, National University of Singapore

MZUF

Museo Zoologico La Specola, Universita di Firenze

RMNH

National Museum of Natural History, Naturalis

MNHN

Museum National d'Histoire Naturelle

UF

Florida Museum of Natural History- Zoology, Paleontology and Paleobotany

MPL

Musee de Port Louis

Kingdom

Animalia

Phylum

Arthropoda

Class

Malacostraca

Order

Decapoda

Family

Portunidae

Genus

Portunus

Loc

Portunus segnis ( Forskål, 1775 )

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

Portunus (Portunus) segnis

Ng, P 2008: 152
2008
Loc

Portunus pelagicus

Corsini-Foka, M 2004: 83
Galil, B 2002: 114
Bahmani, M 1997: 2
Hornby, R 1997: 75
Carpenter, K & Krupp, D 1997: 38
Jones, D 1986: 161
Titgen, R 1982: 118
Kensley, B 1981: 42
Basson, P & Burchard, J 1977: 224
Heath, J 1973: 2
Pretzmann, G 1971: 47
Crosnier, A 1962: 43
Guinot, D 1962: 10
1962
Loc

Lupa pelagica

Fourmanoir, P 1954: 7
Barnard, K 1950: 152
1950
Loc

Portunus mauritianus

Ward, M 1942: 79
1942
Loc

Neptunus (Neptunus) pelagicus

Hashmi, S 1963: 239
Hashmi, S 1963: 115
Stephensen, K 1946: 124
Parisi, B 1916: 171
1916
Loc

Neptunus pelagicus

Chandy, M 1973: 402
Pretzmann, G 1971: 471
Gruvel, J 1936: 50
Kohli, G 1921: 85
Klunzinger, C 1913: 336
Nobili, G 1906: 190
Man, J 1888: 328
Paul'son, O 1875: 61
Hoffmann, C 1874: 7
1874
Loc

Portunus (Portunus) pelagicus

Ng, P 2008: 152
Audouin, V 1827: 261
Audouin, V 1826: 83
1826
Loc

Cancer segnis Forskål, 1775: 18

Forskal, P 1775: 18
1775
Loc

Cancer pelagicus Forskål, 1775: 89

Forskal, P 1775: 89
1775