DIAGNOSTIC REVISION FOR THE MESOZOIC TETRAPOD ICHNOSPECIES BRASILICHNIUM ELUSIVUM (LEONARDI, 1981) (MAMMALIA) FROM THE BOTUCATU FORMATION, PARANÁ BASIN, BRASIL

Marcelo Adorna Fernandes, Ismar de Souza Carvalho

Abstract


The Brasilichnium elusivum
ichnospecies was described for the first time in Brazil by Leonardi, in eocretaceous (Neocomian) continental
aeolian deposits from Botucatu Formation, Paraná Basin, and it corresponds to trackways of a small
sized mammal. The tetrapod ichnofossils studied at the present work were identified and collected at the
São Bento quarry, located in the city of Araraquara, São Paulo State. The purpose of this study is to report
some new data diagnosis to B. elusivum, due the occurrence of well preserved samples that could serve as
base of comparison with the holotype and first paratype, and allowed to determine the ectaxonic character
and the tetradactyly (digits II-III-IV-V) in semi-plantigrade condition of the hind footprints. The tetradactyly
was also observed in the fore autopodia. The heteropody or the homopody, in the occurrence of
mammal ichnofossils, was interpreted as the result of preservational conditions associated to distinctive
locomotor responses of the same animal during its dislocation across the sand dunes of the Botucatu paleodesert

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