Systematics and identification ⁵

Alpheus normanni belongs to the Sulcatus species group within the genus Alpheus (Kim and Abele 1988). Originally described as Alpheus affinis by Kingsley (1878a), this species is named after the Rev. A.M. Norman, who pointed out to Kingsley that the original name for the species (affinis) was already occupied. Type locality: Pacific coast of Panama (Chace 1972, Kim and Abele 1988). Kim and Abele (1988) suggested restricting A. normanni to the eastern Pacific based on morphological differences between the Pacific and Atlantic forms, in which case western Atlantic species would be known as A. packardii (Kingsley 1880). Anker (2001) also suggested the eastern Pacific and Western Atlantic forms will be distinct species once a formal taxonomic revision of the A. normanni complex is done; this is supported by molecular data suggesting at least three species in the complex (Williams et al. 2001). For additional descriptions, see Christoffersen 1979, Williams 1984, Kim and Abele 1988.

Natural history ⁶

Alpheus normanni, like other snapping shrimp in the genera Alpheus and Synalpheus, have powerful major "snapping" claws. Although these claws are primarily used in interspecific or intraspecific agonistic interactions, Beal (1983) demonstrated that A. normanni and the related species A. heterochaelis also use their major snapping claw for predation-- specifically, to crush and consume juvenile clams (Mercenaria mercenaria). Female shrimp of both species exhibited a higher predation rate than males, despite (in A. heterochaelis) having a smaller major chela relative to body size than males. Nolan and Salmon (1970) conducted an extensive study of the behavior of both A. normanni and A. heterochaelis. They noted that shrimp in the laboratory tended to seek shelter (hiding alongside or under hard objects), and dug shelters or burrows with their legs and pleopods. Individuals tended to fight over available shelters (lunging forward, fanning, cocking their claw, touching head appendages, chasing, or snapping); in interspecific interactions (A. heterochaelis paired with A. normanni), the larger individual tended to dominate.

Distribution ⁷

Bermuda; around Cape Charles, Va. And lower Chesapeake Bay through Gulf of Mexico and West Indies to Brazil

Morphology ⁸

Maximum body size is 10 mm carapace length (A. normanni Atlantic, Williams 1984), 7.9 mm carapace length (A. normanni Pacific, Kim and Abele 1988). Color likely varies among localities; Williams (1984) compiled several color descriptions (following): body gray or dullish green, sometimes with median lateral whitish stripe, often mottled with dark green or brown; pale spot behind each eyes; major chela darker green and usually banded with yellow or yellowish brown on inner surface, occasionally with 2 pale bands and blackish fixed finger.

Reproduction and life history ⁹

Knowlton (1973) studied larval development of this species and noted that it had "extended" larval development lasting several weeks, with small eggs and five larval stages. Fecundity of this species has also been studied by Corey and Reid (1991).

Link to Access Genomic Data ¹⁰

http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?id=87362&lvl=0

Sources and Credits

1. (c) matbio, all rights reserved
2. (c) FWC Fish and Wildlife Research Institute, some rights reserved (CC BY), http://farm8.staticflickr.com/7239/13984556614_7d109a6643_o.jpg
3. (c) FWC Fish and Wildlife Research Institute, some rights reserved (CC BY), http://farm3.staticflickr.com/2903/13980940591_7c39357586_o.jpg
4. (c) FWC Fish and Wildlife Research Institute, some rights reserved (CC BY), http://farm6.staticflickr.com/5055/13984113675_80475638c0_o.jpg
5. (c) Hultgren, Kristin, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/11003036
6. (c) Hultgren, Kristin, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/11003032
7. (c) WoRMS for SMEBD, some rights reserved (CC BY), http://eol.org/data_objects/28471143
8. (c) Hultgren, Kristin, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/11003031
9. Adapted by matbio from a work by (c) Hultgren, Kristin, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/11003033
10. (c) Emily Rose Sharkey, all rights reserved

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