title: Extinct and extant sand dollars (Clypeasteroida: Echinoidea) from Uruguay.
abstract: We summarize information concerning Recent and Pleistocene-Holocene Uruguayan sand dollars (Mellitidae), as well as Miocene taxa (Monophorasteridae). Recent and Pleistocene-Holocene species (Encope emarginata, Mellita quinquiesperforata, and Leodia sexisperforata) are at their southernmost limits of distribution, with only E. emarginata recorded further south than Uruguay. Lower temperatures to the south, and/or the Rio de la Plata salinity barrier are suggested as controlling factors of these distributions. During the Miocene, the sea temperatures were notably higher than at present, and it was at this time that the extinct genera Monophoraster and Amplaster reached their maximum diversity in Uruguay. The family Monophorasteridae is the basal sister group of the Mellitidae.
authors.affiliation: Departamento de Evolución de Cuencas, Facultad de Ciencias, Iguá 4225, 11400 Montevideo, Uruguay. smart@fcien.edu.uy
authors.forename: Sergio
authors.initials: S
authors.lastname: Martínez
authors.forename: Rich
authors.initials: R
authors.lastname: Mooi
mesh_terms: D000818:Animals; D044822:Biodiversity; D053476:Extinction, Biological; D005580:Fossils; D010802:Phylogeny; D011156:Population Density; D011157:Population Dynamics; D012617:Sea Urchins / Q000145:classification / Q000502:physiology*; D013045:Species Specificity; D013696:Temperature; D014583:Uruguay