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Villarrica (Permian of Paraguay)

Also known as Villa Rica; Espinillo; Yhovy, Jhovy; Paraná Basin

Where: Guairá, Paraguay (25.8° S, 56.5° W: paleocoordinates 43.6° S, 36.2° W)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: ? San Miguel Formation (Independencia Group), Artinskian (290.1 - 279.5 Ma)

• The beds in question were not mentioned under a formational name by Beder (1923) but were correlated with the "Rio Rasto" and "Estrada Nova" beds of the Passa Dois Group of Brazil. Báez Presser et al. (2004, Bol. Mus. Nac. Hist. Nat. Paraguay 15) apply the modern stratigraphic nomenclature and suspect that all(?) mesosaur remains from the Paraná Basin of Paraguay are from the San Miguel Formation, the lower of the two formations of the Independencia Group. Rapalini et al. (2006, Earth Planets Space 58), based on magnetostratigraphy, ascertain a late Middle Permian/early Late Permian age for the Tacuary Fm. which overlies the San Miguel Fm. Given that the Tacuary Fm. comprises the most part of the Independencia Group (see fig. 2 in Fúlfaro et al., 1997, Int. Geol. Rev. 39(8)) and that mesosaur remains in the San Miguel Fm. strongly argue for a Lower Permian age (for details see comments on stratigraphy in other PBDB collections containing mesosaurids), the present collection is tentatively assigned to the Artinskian.

• group of beds-level stratigraphic resolution

Environment/lithology: marine; ooidal, red, white, yellow, cherty/siliceous sandstone and black, red, blue claystone

• There is no consensus about the true nature (lacustrine/brackish/fully marine) of the water body in which the mesosaurs lived. The environment is tentatively chosen to have been marine. The deposits appear to represent a nearshore equivalent of the lime/dolo mudstones and shales of the Irati Formation of Brazil.

Size class: macrofossils

Preservation: mold/impression

Collected by R. Beder, V.O. Filippi Amábile, among others

Collection methods: quarrying, surface (float),

• The specimen figured by Frech (1901, Lethaea geognostica part I: Lethaea palaeozoica, vol. 2, issue 3) must have been collected on the threshold of the 20th century and was then reposited in the "Hamburger Museum" (and still is?). The specimens reported by Beder (1923) were collected in the early 20s of the 20th century and were then stored in the Bureau of Mines and Energy in Buenos Aires but now are unlocatable (Filippi Amábile, 2001, Bol. Mus. Nac. Hist. Nat. Paraguay 13). Beder did not find complete individuals but was told that quarry workers did so who did not keep them because they did not know about their scientific value. The newest findings were made by Filippi Amábile on the threshold of the 21st century and these specimens are reposited in the National Museum of Natural History of Paraguay (Filippi Amábile, 2001).

Primary reference: R. Beder. 1923. Sobre un Hallazgo de Fósiles Pérmicos en Villarrica (República del Paraguay). Boletín da la Academia Nacional de Ciencias en Córdoba (República Argentina) 27(1/2):9-12 [J. Mueller/T. Liebrecht/T. Liebrecht] more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 90832: authorized by Johannes Mueller, entered by Torsten Liebrecht on 18.08.2009

Creative Commons license: CC BY (attribution)