Newman noted there were multiple fossil taxa in this genus, but didn't classify any except for the type species †C. concavus.[3]
In 1992, Victor A. Zullo revised the genus. He created a new subfamily, Concavinae, with TamiosomaConrad, 1856 (the senior synonym of Menesiniella according to Zullo[b]), Arossia and Concavus among its genera. With his revision, Concavus only consists of the two species C. concavus and C. crassostricola.[1]
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.[7]
^ abcdZullo, Victor A. (1992). "Revision of the Balanid Barnacle Genus Concavus Newman, 1982, with the Description of a New Subfamily, Two New Genera, and Eight New Species". Memoir (The Paleontological Society). 27: 1–46. JSTOR1315604.
^Zullo, Victor A. (1984). "New Genera and Species of Balanoid Barnacles from the Oligocene and Miocene of North Carolina". Journal of Paleontology. 58 (5): 1328–1330. JSTOR1304855.