Bibliographic citations
Varas, R., (2021). Caracterización sistemática y biogeografía de la comunidad de lobos marinos (Carnivora, Otariidae) del Neógeno tardío - Cuaternario de la cuenca Pisco este (Arequipa) y su relación con el sistema biótico de Humboldt [Universidad Peruana Cayetano Heredia]. https://hdl.handle.net/20.500.12866/10045
Varas, R., Caracterización sistemática y biogeografía de la comunidad de lobos marinos (Carnivora, Otariidae) del Neógeno tardío - Cuaternario de la cuenca Pisco este (Arequipa) y su relación con el sistema biótico de Humboldt []. PE: Universidad Peruana Cayetano Heredia; 2021. https://hdl.handle.net/20.500.12866/10045
@mastersthesis{renati/493916,
title = "Caracterización sistemática y biogeografía de la comunidad de lobos marinos (Carnivora, Otariidae) del Neógeno tardío - Cuaternario de la cuenca Pisco este (Arequipa) y su relación con el sistema biótico de Humboldt",
author = "Varas Malca, Rafael Martin",
publisher = "Universidad Peruana Cayetano Heredia",
year = "2021"
}
Hydrarctos lomasiensis represents the first known migration of otariids to the ancient Humboldt system. However, the lack of consensus on its phylogenetic position, unknown stratigraphic origin and the scarce paleontological record of otarids in the Plio-Pleistocene, make it difficult to understand this important biogeographic event. Craniodentary and mandibular remains of seven new specimens are described comparatively, coming from the Caracoles (2.7-1.9 Ma) and Pongo (~ 2-1 Ma) formations, from the fossiliferous area of Sacaco, Arequipa. Phylogenetic analysis using maximum parsimony recovers them as sister group of Hydrarctos lomasiensis, and this one within the Arctocephalus clade, but with little statistical support. It is argued in favor of a position within the crown-clade otariids for Hydrarctos. The evidence supports the hypothesis of otariids migration to the southern hemisphere from the northeastern Pacific basin, after the warm period of the middle Pliocene (~ 3 Ma). The western coasts of South America possibly received multiple waves of colonizing species, beginning with the sympatric Otaria, Hydrarctos spp. and possibly the ancestral Arctocephalus. The vertebrate community of this locality preliminarily indicates that it is different from that of the early Pliocene and represents a stage prior to the consolidation of the Humboldt’s modern biota. This restructuring would have started in the late Pliocene, a period in which the resident seals become extinct.
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