Abstract
Raptorial sperm whales of the genus Livyatan were described from the Miocene of Peru and Chile. Revision of paleontological collections resulted in the finding of isolated teeth belonging to aff. Livyatan sp. coming from Early-Middle Miocene strata from Bajo del Gualicho area, Rio Negro Province, Argentina. These specimens represent the first finding of this genus in the Southwestern Atlantic Ocean and indicate that Livyatan-like forms were more widespread than previously thought. The reasons of the extinction of such predatory whales are still uncertain, but it is not improbable that it may be correlated with competition for food resources with globicephaline delphinids. This hypothesis still rests on weak evidence and should be evaluated through findings of new specimens, as well as detailed analysis of the fossil record.
Highlights
The record of macroraptorial stem-Physeteroidea in South America is composed by two species of the genus Acrophyseter (A. deinodon and A. robustus) and the giant Livyatan melvillei, all of them from Late Miocene deposits of the Pisco Formation, Peru (Lambert et al, 2016; Bianucci et al, 2016; Di Celma et al, 2016)
Gutstein et al (2015) mentioned the possible presence of Livyatan in Chile, represented by an isolated tooth coming from the Bahía Inglesa Formation (Late Miocene/Late Pliocene)
We report the first record assignable to Livyatan sp. from Argentina, and we briefly discuss its palaeobiogeographical implications
Summary
The record of macroraptorial stem-Physeteroidea in South America is composed by two species of the genus Acrophyseter (A. deinodon and A. robustus) and the giant Livyatan melvillei, all of them from Late Miocene deposits of the Pisco Formation, Peru (Lambert et al, 2016; Bianucci et al, 2016; Di Celma et al, 2016). Gutstein et al (2015) mentioned the possible presence of Livyatan in Chile, represented by an isolated tooth coming from the Bahía Inglesa Formation (Late Miocene/Late Pliocene). The Saladar Member is characterized by the presence of intermixed sandstone, coquina and pelitic levels It evidences a transgressive environment of shallow waters with an evolution of facies that changes from platform sediments to typical beach deposits (Reichler, 2010). The root is subconical, robust and slightly distally curved It shows a relatively thick layer of cement and a core of dentine. The root shows apicobasal ridges, grooves, and rugosities This ornamentation becomes attenuated from the base to the tip of the preserved portion of the element. The only difference between the specimens is that BAR2601 lacks any indication of occlusal facets This may be due to incomplete preservation. BAR-2601: Maximum apicobasal height (as preserved): 178 mm; Maximum mesiodistal diameter: 72 mm
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
