Inadequate descriptions and diagnoses of representatives of the sea anemone genus Anthopleura from the Gulf of Mexico and Caribbean have led to confusion about species identity. Multiple names have been applied to a single species, and the same name has been used for multiple
species, obscuring the distinction between species and confusing accounts of anatomy, life history, and ecology. Because Anthopleura krebsi Duchassaing and Michelotti, 1860, the type species of the genus, is among these species, reconciling taxonomy, anatomy, and biology is essential.
We conclude from our investigation of live specimens, museum collections, and published records that the sea anemones in the Gulf of Mexico and Caribbean that have been considered members of Anthopleura belong to four valid species: A. krebsi, Anthopleura pallida Duchassaing
and Michelotti, 1864, Anthopleura texaensis (Carlgren and Hedgpeth, 1952), and Isoaulactinia stelloides (McMurrich, 1889). We redescribe these species, providing differential diagnoses that use characters visible in the field and those evident after preservation; we
also identify synonyms and reconcile published records of these species with our circumscriptions. Although all of the features that have been proposed as defining or diagnosing Anthopleura are seen in A. krebsi, a comprehensive study of species in Anthopleura, Aulactinia,
Bunodactis, Bunodosoma, and Gyractis is necessary to evaluate the systematic value of currently used characters.
The Bulletin of Marine Science is dedicated to the dissemination of high quality research from the world's oceans. All aspects of marine science are treated by the Bulletin of Marine Science, including papers in marine biology, biological oceanography, fisheries, marine affairs, applied marine physics, marine geology and geophysics, marine and atmospheric chemistry, and meteorology and physical oceanography.