Portunus gibbesii (Stimpson, 1859) Iridescent Swimming Crab Infraorder Brachyura Family Portunidae References used: Williams (1984) Diagnostic characters: Carapace about twice as wide as long with eight frontal teeth; one or more small, naked iridescent patches near anterolateral margin of carapace (at base of teeth); chelipeds long, slender, especially in males (sexually dimorphic). Habitat: Common in shallow shelf waters, lower reaches of bays. Found on sandy or muddy bottoms, surface to 393 m. Range: Massachusetts through the Gulf of Mexico to French Guiana. Iridescent patches Guide to Shelf Invertebrates, Gulf of Mexico - Perry and Larsen © 2004 Draft 4/24/04 Sex Determination for P. gibbesii Immature female Mature female Male Guide to Shelf Invertebrates, Gulf of Mexico - Perry and Larsen © 2004 Draft 4/24/04 Portunus sayi (Gibbes, 1850) Sargassum Swimming Crab Infraorder Brachyura Family Portunidae References used: Williams (1984), Powers (1977) Diagnostic characters: Carapace with six frontal teeth including inner orbitals, nearly twice as wide as long, smooth and polished to naked eye; chelipeds of moderate length, larger in males than females; brown in color or purplish with cloudings of olive green or light brown, irregular white or flesh- colored spots; orange margins on spines of chelipeds. Habitat: Normally pelagic, living among floating Sargassum. Range: Nova Scotia through the Gulf of Mexico to Guianas; Canary Islands; Morocco. Guide to Shelf Invertebrates, Gulf of Mexico - Perry and Larsen © 2004 Draft 4/24/04 Portunus spinicarpus (Stimpson, 1871) Longspine Swimming Crab Infraorder Brachyura Family Portunidae References used: Williams (1984) Diagnostic characters: Carapace about twice as wide as long with six frontal teeth; chelipeds long, slender; carpus with 2 spines, outer small, inner long and extending along side of hand to near base of dactyl; in females this spine is much shorter. Habitat: Found over mud and sand bottoms from 9 to 550 m. Range: North Carolina through the Gulf of Mexico to Brazil. Arrows indicate spine along side of hand. Top: Female Bottom: Male Guide to Shelf Invertebrates, Gulf of Mexico - Perry and Larsen © 2004 Draft 4/24/04 Portunus spinimanus Latreille, 1819 Blotched Swimming Crab Infraorder Brachyura Family Portunidae References used: Williams (1984), Powers (1977) Diagnostic characters: Carapace with eight frontal teeth including bilobed inner orbitals. Carapace narrow, anterolateral margins forming arc of a circle with center near the cardiac region. One spine on upper margin of palm near articulation of dactyl. Ridges of carapace, spines of chelipeds, fingers and tips of legs reddish-brown; anterolateral teeth reddish at base, white at tips; merus, carpus and hand of chelipeds with white blotches. Habitat: Common in waters over inner continental shelf, occasionally lower reaches of bays. Found on sandy or muddy bottoms, coral reefs. Range: New Jersey through the Gulf of Mexico to Brazil. Guide to Shelf Invertebrates, Gulf of Mexico - Perry and Larsen © 2004 Draft 4/24/04 Sex Determination for Portunus spinimanus Immature female Mature female Male Guide to Shelf Invertebrates, Gulf of Mexico - Perry and Larsen © 2004 Draft 4/24/04 .