Proposal for Ichnotaxonomic Allocation of Therapsid Footprints from the Botucatu Formation (Brazil)

ABSTRACT

A new ichnospecies, Brasilichnium anaiti, is erected on material from the Botucatu Formation of Brazil. The general morphology supports ichnotaxonomic similarity between the new ichnotaxon and Brasilichnium elusivum Leonardi, 1981, even if a separation at the ichnospecies level is evident, based on differences in shape and arrangement of pes digit marks along with a clear dimensional gap between both ichnotaxa. Similar forms from the Lower Jurassic of the United States are known and should be included under this new ichnotaxonomic label, based on shared morphological features. B. anaiti is constantly associated with B. elusivum in dune foresets of hyperarid paleoenvironments, to which these forms are restricted. This makes B. anaiti a further element of the Brasilichnium ichnocoenosis in the larger framework of the Chelichnus ichnofacies. Re–evaluation of possible trackmakers highlights the difficulties of unequivocal referring this ichnotaxon to a specific producer, but restrains potential trackmakers to early mammaliamorph therapsids.

KEYWORDS:

• Botucatu Formation
• Brasilichnium anaiti
• Brazil
• Mammaliamorph therapsids
• Paleoerg

Acknowledgments

This work is intended as a contribution for the project “Dune's Life: the Track Record of a Mesozoic Warm Desert.” The University of São Paulo, at Ribeirão Preto, is acknowledged for support and logistics. We are indebted to Lilia Maria Dietrich Bertini for constant help and assistance. Cibele Gasparelo Voltani is kindly acknowledged for logistic support during collection analysis. We wish to thank Ignacio Díaz-Martínez (Universidad Nacional de Río Negro (Argentina) and an anonymous reviewer for helpful comments to the original manuscript. Lorenzo Marchetti (Università degli Studi di Padova) is acknowledged for further review. We would like to thank Hendrik Klein (Saurierwelt Paläontologisches Museum, Neumarkt) for constant editorial assistance.

Additional information

Funding

S. D'Orazi Porchetti's research was supported by a Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Post–Doctoral Grant (Process Number 2013/01930–1).