Phylogenetic analysis and reconstrution of the paleohabitat of three fossil cetaceans from the miocene of Portugal

• Autor(a) principal: Figueiredo, Rodrigo Silva
• Data de Publicação: 2022
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10773/36570
• topic: Evolution; Paleontology; Paleoecology; Mysticeti; Cetotheriidae; Phylogeny; Anatomy

Understanding the phylogeny of the different families of fossil cetaceans can give us insights on the evolution and adaptations that emerged over millions of years in the group of the largest animals that ever existed, from the most primitive semiaquatic protocetids to the whales that we see today crossing the oceans. For a long time, the Cetotheriidae family has been seen as a problematic clade, containing various species probably not closely related. In the past two decades there were various studies trying to resolve the phylogeny of this group. In 1831, Alexandre Vandelli collected three cetotheriid skulls were found during a gold exploration at Adiça beach (Portugal). These specimens constituted the first vertebrate Portuguese fossils described in the literature. Almost a century later, in 1914, another skull was associated to the “Vandelli skulls” by Jacinto Pedro Gomes during a survey on the Museu Nacional de História Natural collections with no information on how and when this skull appeared. In 1941, Remington Kellogg refers that one of the original “Vandelli skulls” is no longer present in the Museu Nacional de História Natural collections. Up until this day, there is no information on how and exactly when the fourth skull and one of the original three “Vandelli skulls” appeared and disappeared, respectively. Since their discovery, various attempts to describe these specimens were made but none of them were based on direct observations and no comprehensive phylogenetic analysis have included the three skulls still available. The present study provides a detailed anatomic description, a up to date phylogenetic analysis and a palaeoecological reconstruction of these specimens, clarifying their relationships within the Cetotheriidae family and fostering the importance of these historical specimens to the modern comprehension of fossil whale evolution. In addition, our results support that Cephalotopis nectus is a valid species (with an emended diagnosis). We also concluded that two of the Vandelli specimens should be included under a new genus, forming two new species of fossil whales (new combinations).