title: Morphometry, bite-force, and paleobiology of the late miocene caiman Purussaurus brasiliensis.
abstract: Purussaurus brasiliensis thrived in the northwestern portion of South America during the Late Miocene. Although substantial material has been recovered since its early discovery, this fossil crocodilian can still be considered as very poorly understood. In the present work, we used regression equations based on modern crocodilians to present novel details about the morphometry, bite-force and paleobiology of this species. According to our results, an adult Purussaurus brasiliensis was estimated to reach around 12.5 m in length, weighing around 8.4 metric tons, with a mean daily food intake of 40.6 kg. It was capable of generating sustained bite forces of 69,000 N (around 7 metric tons-force). The extreme size and strength reached by this animal seems to have allowed it to include a wide range of prey in its diet, making it a top predator in its ecosystem. As an adult, it would have preyed upon large to very large vertebrates, and, being unmatched by any other carnivore, it avoided competition. The evolution of a large body size granted P. brasiliensis many advantages, but it may also have led to its vulnerability. The constantly changing environment on a large geological scale may have reduced its long-term survival, favoring smaller species more resilient to ecological shifts.
authors.affiliation: Departamento de Geologia, Universidade Federal de Pernambuco, CEP 50740-530, Recife, Pernambuco, Brazil.
authors.forename: Tito
authors.initials: T
authors.lastname: Aureliano
authors.affiliation: Departamento de Geologia, Universidade Federal do Rio de Janeiro, CEP 21949-900, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Aline M
authors.initials: AM
authors.lastname: Ghilardi
authors.affiliation: Laboratório de Pesquisas Paleontológicas, Universidade Federal do Acre, CEP 69915-900, Rio Branco, Acre, Brazil.
authors.forename: Edson
authors.initials: E
authors.lastname: Guilherme
authors.affiliation: Laboratório de Pesquisas Paleontológicas, Universidade Federal do Acre, CEP 69915-900, Rio Branco, Acre, Brazil.
authors.forename: Jonas P
authors.initials: JP
authors.lastname: Souza-Filho
authors.affiliation: Ecoinformatics Studio, P. O. Box 46521, CEP 20551-970, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Mauro
authors.initials: M
authors.lastname: Cavalcanti
authors.affiliation: Instituto de Biologia, Universidade Federal de Uberlândia, CEP 38400-902, Uberlândia, Minas Gerais, Brazil.
authors.forename: Douglas
authors.initials: D
authors.lastname: Riff
mesh_terms: D000489:Alligators and Crocodiles / Q000033:anatomy & histology* / Q000502:physiology; D000818:Animals; D005075:Biological Evolution; D001732:Bite Force; D049628:Body Size / Q000502:physiology; D004032:Diet; D017753:Ecosystem; D005247:Feeding Behavior / Q000502:physiology*; D005580:Fossils; D007568:Jaw / Q000033:anatomy & histology / Q000502:physiology; D011235:Predatory Behavior / Q000502:physiology*; D013020:South America