Atlantic Mud Crab
Panopeus herbstii
Summary 2
Panopeus herbstii (the black-fingered mud crab, black-clawed mud crab, Atlantic mud crab or sometimes common mud crab) is a true crab, belonging to the infraorder Brachyura, and is the largest of the mud crabs.
Description 3
The Atlantic mud crab, Panopeus herbstii, is one of many species of mud crabs belonging to the family Xanthidae. Crabs included in Panopeus and related genera have five teeth lining the outside of the carapace on each side, the first two mostly fused (Gosner 1978).The fingers, or top and bottom portions of the closable claw, are usually black to brown in most species; whereas, the interior portion at the base of the claw, called the palm, is usually pale. The claws are distinctly unequal in size, and the body is brownish. The carapace of P. herbstii is brownish green and slightly granular in texture, with sharp 2nd, 3rd, and 4th marginal teeth on either side (Kaplan 1988, Voss 1980). The appendages bearing the claws, called chelipeds, are darker and often spotted. Both fingers on each claw are black, and the color of the lower finger often extends up the palm. An enlarged, white tooth is present at the base of the upper finger on the larger claw (eg. Ruppert & Fox 1988). The 3rd maxilliped, or feeding appendage, is marked with a red spot in males, sometimes in females (Gosner 1978). All walking legs are hairy and slender (Voss 1980).
Distribution 4
Virginian, south side of Cape Cod, extending northward of the subprovince limit.
Size 5
The maximum age of P. herbstii is unknown, and the lifespan can vary with food availability and environmental factors. With the exception of the stone crab, Menippe mercenaria, the Atlantic mud crab is the largest xanthid species in the southeast United States (Ruppert & Fox 1988). The maximum reported carapace width for P. herbstii is 6.4 cm (Ruppert & Fox 1988), though most specimens are much smaller at widths of 3-4 cm (Gosner 1978, Kaplan 1988).
Look alikes 6
Xanthid crabs are a large, often confusing group with subtle differences between some species. The largest member of this family in the southeast United States is the edible Florida stone crab, Menippe mercenaria. Other smaller mud crabs possibly confused with P. herbstii include: the strongtooth mud crab, Panopeus bermudensis; Say mud crab, Dyspanopeus sayi; Florida grassflat crab, Neopanope packardii; and the flatback mud crab, Eurypanopeus depressus. Like the Atlantic mud crab, dark color on the lower finger of all these species extends onto the palm of the claw (Kaplan 1988). However, the average size of P. herbstii is significantly larger than any of the following mud crabs.The carapace of the strongtooth mud crab reaches a length of 1cm, has four sharp teeth on the edge of each side, and is dull red in color (Kaplan 1988). The claws are grayish, with dark lower fingers, white fingertips and a tan spot at the base. The carapace of the Say mud crab reaches a length of 2.1 cm, and is bluish green, brown or buff, with reddish brown spots on a yellow background (Kaplan 1988). The first marginal tooth on each side is rounded, and the remaining teeth are slanted but not sharp. The Florida grassflat crab attains a length of 1.3 cm, with claw coloration similar to the previously mentioned species (Kaplan 1988). The marginal teeth on the carapace are similar to those of D. sayi, but the last three marginal carapace teeth are spiny.The flatback mud crab reaches a length of 1.8 cm, is mottled grayish or dark olive-brown with the last three marginal teeth large and sharp (Kaplan 1988). The fingertips are spoon-shaped, with small teeth at the base of the upper finger.II . HABITAT & DISTRIBUTION Regional Occurrence & Habitat Preference: The range of P. herbstii extends from Massachusetts to Brazil (Gosner 1978, Kaplan 1988). Most populations inhabit muddy bottoms, mainly in mangrove swamps and oyster beds (Kaplan 1988, Ruppert & Fox 1988, Voss 1980). However, both adults and juveniles can also be found on jetty rocks, shell or cobble bottoms, and marsh edges (Dittel et al. 1996). In oyster beds and under rocks, individuals may excavate shallow burrows to a depth of 4-10 cm (Williams 1984).
Reproduction 7
As with most decapod crustaceans, fertilization occurs during copulation. The male transfers sperm-filled cases, called spermatophores, to the female. After the eggs are fertilized, the female broods them on her abdomen until hatching. Reproduction is seasonal in some locations, and is likely linked to water temperature and food availability. In Delaware Bay, P. herbstii spawns throughout the summer months (Rodriguez & Epifanio 2000). Embryology / Larval Development:Like many other crabs, P. herbstii females carry large broods of eggs on their abdomen, often referred to as sponges. Once hatched, larvae pass through four zoeal stages and one megalopa before settling to the benthos and metamorphosing into juveniles (Williams 1984). Zoeae of mud crabs have characteristically large spines that have developed as protection against predatory fishes (Morgan 1989). After release, larvae are retained within estuarine waters during the entire planktonic period by undergoing vertical migration and utilizing inward-flowing bottom currents (eg. Dittel & Epifanio 1982).
Link to Access Genomic Data 8
http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=53944&lvl=0
Sources and Credits
- (c) matbio, all rights reserved
- Adapted by matbio from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Panopeus_herbstii
- Adapted by matbio from a work by (c) Smithsonian Marine Station at Fort Pierce, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/11527438
- Adapted by matbio from a work by (c) WoRMS for SMEBD, some rights reserved (CC BY), http://eol.org/data_objects/28471270
- Adapted by matbio from a work by (c) Smithsonian Marine Station at Fort Pierce, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/11527443
- Adapted by matbio from a work by (c) Smithsonian Marine Station at Fort Pierce, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/11527440
- (c) Smithsonian Marine Station at Fort Pierce, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/11527442
- (c) Emily Rose Sharkey, all rights reserved
