Tracheria troyana (Krapovickas and Nasif, 2011): Redefinition, Environmental Distribution, and Heritage Conservation

ABSTRACT

The South American caviomorph ichnogenus Tracheria troyana is reevaluated here based on recently discovered specimens that allow a more thorough investigation of footprint taphonomy and ichnotaxonomy. The footprints include detailed autopodium morphology and more complete gait patterns than previously reported. The redefinition of T. troyana involves key aspects as digit impressions of the manus asymmetrically arranged and digit V being the shortest and at times do not print. It generally lacks metacarpal pads, resulting in almost digitigrade impressions and regularly preserved as tridactyl footprints. In the pes imprints, digits have a symmetrical arrangement. Phalangeal and metapodial pad impressions are preserved, occasionally showing the presence of two heel pads. Trackways denote a marked overstep in which the pes impressions are placed in front of the manus. New data about T. troyana environmental distribution shows that typically characterizes overbank facies of anastomosing and meandering fluvial systems, which may be reflecting a habitat preference the producer. Here, we also present new digitized 3D images of the original type material of T. troyana, in order to preserve these materials, which were previously only available for viewing in the field.

KEYWORDS:

• 3D modeling
• Vinchina Formation
• Miocene
• Fluvial setting
• Dinomyid caviomorph footprints

Acknowledgments

We are grateful to C. O. Limarino, Y. Díaz, J. Schencman, H. Tassone, and P. Puerta for their collaboration during field work. We thank J. J. Scott for her comments that greatly improved the manuscript.

Additional information

Funding

Funding for this research was provided by projects PICT 2011–2334, PICT 2014–1921 (V.K.), PICT 2012–727 (Limarino), and PICT 2014–1963 (S.M.).