Heavy Marsh Crab

Sesarma reticulatum (Say, 1817)

Ocypode reticulatus Say, 1817:73, pl. 4: fig. 6.

Ocypode (Sesarma) reticulatus.—Say, 1818:442.

Sesarma cinerea.—DeKay, 1844:15.—White, 1847:38.

Sesarma reticulata.—Gibbes, 1850:180.—Stimpson, 1862:66.—Smith, 1870:156.—Ortmann, 1897:333.—Hay and Shore, 1918:448, pl. 36: fig. 12. Sesarma (Sesarma) reticulata.—Rathbun, 1897a:89.

Sesarma (Sesarma) reticulatum.—Rathbun, 1918:290, pl. 77.—Williams, 1965:221, fig. 205.—1984:466, fig. 374.—Abele, 1973a:380, fig. 1D, E.

Sesarma reticulatum.—Humes, 1941:379.—Gray, 1957:34.—Teal, 1959:1.—Crichton, 1960:3.—Costlow and Bookhout, 1962:281.—Seiple, 1979:77.—Felgenhauer and Abele, 1983:187.—Abele and Kim, 1986:63, 673b.

MATERIAL EXAMINED.—Massachusetts: Woods Hole, 4, 2 ovigerous , 10 Jul 1910, V.N. Edwards, USNM 45530; 1, USNM 32482; Wareham, 4, 1, 21 Jul 1887, USNM 12782; Acushnet River (New Bedford), 2, USNM 5784.

North Carolina: Near Beaufort, 10, 10, 1971, L.G. Abele.

Florida: Ft. Pierce, Pepper State Park, 2, 5 Nov 1977, L.G. Abele, R.H. Gore; Indian River, Sebastian Inlet Park, 13, 13 (1 ovigerous), 30 Jun 1977, L.G. Abele, R.H. Gore, K. Wilson, K. Rodman; Daytona Beach, 2, 6 Nov 1977, L.G. Abele, K. Heck; Sarasota Bay, 2, USNM 71169; Travertine Quarry, 3, 1, USNM 71302; Alligator Harbor (Franklin Co.), 1 ovigerous .

DESCRIPTION.—Carapace broader than long cl/cb = 0.807±0.02 for males, 0.810±0.02 for females; dorsal surface punctate, regions well defined; lateral striae present. Outer orbital angle acute, margin slightly convex; low, weak tooth proximal to outer orbital angle; lateral margins converging toward midline. Interorbital region subdivided into four low lobes; iw/cb = 0.583±0.02 in males, 0.592±0.01 in females. Frontal region with lateral margins widening distally; anterior margin concave medially.

Eyes well developed, pigmented.

Chelipeds sexually dimorphic; female cheliped relatively smaller, not swollen, with fewer tubercles. Merus with posteromedial margin almost smooth forming arch at subdistal notch; anteromedial margin expanded distally with a few scattered low tubercles. Carpus granular, distinct medial border present slightly flared at anteromedial angle; tuft of setae in proximal medial portion and another at medioventral angle. Palm swollen, smoothly punctate on lateral surface, distinct row of granules dorsally and scattered large tubercles on medial surface; movable finger strongly arched with single proximal and single distal teeth; dorsal surface with about four to six tubercles. Immovable finger with row of three low and one large proximal teeth followed by concave region ending at small distal tooth; finger tips spooned, corneous; immovable one notched.

Walking legs relatively broad; ml/mw of third (fourth pereiopod) 2.05±0.24 in males, 2.16±0.17 in females; dorsal surface of carpus and dorsal and ventral surface of propodus and dactylus with a short, thick pubescence; propodus longer than dactylus.

Male abdomen subtriangular in outline; telson width subequal to length. Gonopod with subrectangular endpiece, curved laterally in distal region.

Female abdomen subcircular in outline; telson width slightly greater than length. Gonopore tear-shaped, level with sternum, widening away from suture; operculum raised above sternum increasing in height at wide end.

COLOR.—From various authors; Williams (1965:221):

Carapace dark olive, nearly black or purple; dark plum colored or bluish-black speckles crowded on grayish background, grayish color showing little except on posterior part; upper part of chelipeds similarly colored but brighter, greater part of palm yellowish, tips of fingers white or yellowish; upper part of legs as carapace; under parts grayish.

MEASUREMENTS.—Males cb 7.1 to 27 mm; females cb 10.7 to 18.2 mm; ovigerous females cb 17.9 to 22.2 mm.

TYPE LOCALITY.—East coast of the United States.

TYPE.—Not extant.

DISTRIBUTION.—Woods Hole, Massachusetts, to at least Indian River County on the east coast of Florida; Sarasota County on the west coast of Florida to Texas. The species is apparently absent from the tip of peninsular Florida (Abele, 1973a).

HABITAT.—Sesarma reticulatum is common in burrows in low areas of Spartina marshes. Crichton (1960) gives notes on the habitat of S. reticulatum in Delaware. Seiple (1979) found S. reticulatum to prefer silty substrates of low salinity (16.2 0/00) in the eulittoral region of Spartina marshes. They occur in burrows in red mangrove swamps in the southern part of their range.

Sesarma reticulatum, the purple marsh crab or simply marsh crab, is a crab species native to the salt marshes of the eastern United States.

Woods Hole Region, Mass., to Volusia County, E Florida; Sarasota, W Florida, to Calhoun County, Tex.