Concavus
Concavus is a genus of barnacles. Species. , WoRMS recognizes the following two species: Taxonomic history. The genus was circumscribed by William A. Newman in 1982. His original list of subgenera and species for the genus was the following: Newman noted there were multiple fossil taxa in this genus, but didn't classify any except for the type species "C. concavus". In 1992, Victor A. Zullo revised the genus. He created a new subfamily, Concavinae, with "Tamiosoma" (the senior synonym of "Menesiniella" according to Zullo), "Arossia" and "Concavus" among its genera. With his revision, "Concavus" only consists of the two  species "C. concavus" and "C. crassostricola". Fossil records. This genus is known in the fossil records from the Oligocene to the Quaternary (age range: from 28.4 to 0.012 million years ago). Fossils are found in the marine strata of United States, Italy, Mexico, Morocco, Algeria, France, Haiti, Madagascar, Panama, Colombia and Slovenia.