A new specimen of Caiman brevirostris (Crocodylia, Alligatoridae) from the late Miocene of Brazil

ABSTRACT

Caiman brevirostris was described based on the basis of late Miocene materials that included a rostral fragment and a right mandibular ramus, but photographs were not provided at that time. In this study, for the first time, we present the holotype materials of this species and a new specimen from the late Miocene of southwestern Amazonia, Brazil. The diagnosis was expanded, and a phylogenetic analysis was conducted. The results from the analysis consistently recover Caiman brevirostris within a clade that includes Caiman latirostris, Caiman cf. C. lutescens, and Melanosuchus. The oldest fossil record of the genus Caiman is from the Oligocene of southeastern Brazil, but these materials are regarded in this study as a nomen dubium due to the absence of any diagnostic features for the specimen. Thus, the oldest record considered valid by this study derives from the middle Miocene of Colombia and may represent the initial radiation of the genus.

SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP

ACKNOWLEDGMENTS

We thank A. M. Sá Teixeira for the drawings in Figures 3 and 4. For access to and assistance with collections, we thank C. Mehling (AMNH), R. Machado (DGM), A. Resetar and K. Lawson (FMNH), J. Cundiff (MCZ), P. Holroyd (UCMP), A. Hastings, K. Krysko, and R. Hulbert (UF), and A. Wynn and J. Jacobs (USNM). We thank A. Hastings, D. Riff, and P. O’Connor for critical review of the manuscript. The FMNH, UCMP, and the Brazilian agencies CAPES and CNPq funded collections visits by D.F.

Handling editor: Patrick O’Connor