Portunus pelagicus, SPECIES-COMPLEX

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 : 225

PORTUNUS PELAGICUS SPECIES-COMPLEX

1. Median teeth frontal teeth minute, inconspicuous, almost obsolete ( Fig. 23B ); western Indian Ocean ............. P. segnis

– Median teeth frontal teeth conspicuous, either small or prominent; eastern Indian Ocean and Western Pacific ......... 2

2. Four spines on anterior margin of cheliped merus ( Fig. 23H ); Australia................................................................ P. armatus

– Three spines on anterior margin of cheliped merus ............. 3

3. Sixth segment of male abdomen relatively shorter, broader ( Fig. 22A ); white spots on the carapace, often merging into broad almost banded reticulations, in particular on the posterior and branchial regions ( Figs. 6A , 10 ); Southeast Asia to northwestern Australia, western Pacific to Japan..................... P. pelagicus

– Sixth segment of male abdomen relatively narrower, more elongate ( Fig. 22C ); carapace covered with spots, rarely merging into short bands ( Figs. 6C , 16 ); eastern Indian Ocean but not Australia............................................................ P. reticulatus

Figures

Fig. 23. Frontal margin and merus of left cheliped A, E, Portunus pelagicus (152.9 × 68.0 mm) (ZRC 2007.233); B, F, P. segnis (134.5 × 62.6 mm) (ZRC 2007.226); C, G, P. reticulatus (138.5 × 60.7.0 mm) (ZRC 2007.222); D, H, P. armatus (133.0 × 66.0 mm) (ZRC 2007.229).

Fig. 22. Male abdominal somites. A, Portunus pelagicus (152.9 × 68.0 mm) (ZRC 2007.233); B, P. segnis (134.5 × 62.6 mm) (ZRC 2007.226); C, P. reticulatus (138.5 × 60.7 mm) (ZRC 2007.222); D, P. armatus (133.0 × 66.0 mm) (ZRC 2007.229).

Fig. 6. Live colours of males. A, Portunus pelagicus (Linnaeus, 1758) (142.7 × 67.1mm) (ZRC 2007.0235), Pulau Tekong, Singapore; B, Portunus segnis (Forskål, 1775) (140.1 × 62.3mm) (ZRC 2007.0220), Tulear, Madagascar (photograph: H. H. Tan); C, Portunus reticulatus (Herbst, 1799) (132.2 × 59.8mm) (ZRC 2007.0223), Chennai, India (photograph: Z. Jaafar); D, Portunus armatus (A. Milne-Edwards, 1861) (no specimen, photograph only) Brisbane, Queensland (photograph: P. J. F. Davie).

Fig. 10. Colour variation in Portunus pelagicus males. A, Taiwan (specimen not preserved) (photograph: C.Y. Tsai); B, Singapore (specimen not preserved) (photograph: M. Ng).

Fig.16. Portunus reticulatus (Herbst, 1799), male (163.4 × 77.2mm) (ZRC 2009.1005), Phuket, western Thailand.