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Arroyo de La Mina (Permian of Uruguay)

Where: Cerro Largo, Uruguay (31.9° S, 54.0° W: paleocoordinates 50.1° S, 37.3° W)

• coordinate estimated from map

• small collection-level geographic resolution

When: Mangrullo Member (Melo Formation), Artinskian (290.1 - 279.5 Ma)

• No statigraphic data is given by Mones (1972). Cernuschi et al. (2006, V South American Symposium on Isotope Geology, http://www.vssagi.com/igcp478/AbstractsVSSAGI/306.pdf) say that mesosaurs in Uruguay occur in bituminous shales of the Mangrullo Member of the Melo Formation. The Mangrullo Mb. has a radiometric age of 279 ± 6 Ma (see Cernuschi et al., 2006 and references therein; absolute age corresponds to the Artinskian according to time scales of Gradstein et al., 2004 and Ogg et al., 2008) and thus appears to represent the same stratigraphic interval as the Irati Formation of Brazil. Fúlfaro et al. (1997, Int. Geol. Rev. 39(8), fig. 2) gives a somewhat different stratigraphic nomenclature in which the three members of the Melo Formation (Frayle Muerto, Mangrullo, and Paso Aguiar) have formational rank and are included in a superordinate group referred to as the Cerro Largo Group. Outcrops of the Mangrullo Fm. are present in the area in question according to the geological map of Uruguay (available under http://www.miem.gub.uy).

• group of beds-level stratigraphic resolution

Environment/lithology: marine; lithology not reported

• not reported but probably bituminous shale

Size class: macrofossils

Collection methods: Mones (1972) lists references mentioning mesosaur findings in the Cerro largo localities

Primary reference: A. Mones. 1972. Lista de los vertebrados fosiles del Uruguay, I. Chondrichthyes, Osteichthyes, Reptilia, Aves [List of the fossil vertebrates of Uruguay, I. Chondrichthyes, Osteichthyes, Reptilia, Aves]. Comunicaciones Paleontologicas del Museo de Historia Natural de Montevideo 1(3):23-35 [M. Carrano/M. Carrano] more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 90863: authorized by Johannes Mueller, entered by Torsten Liebrecht on 20.08.2009

Creative Commons license: CC BY (attribution)