Estudio sistemático de material craneal de misticetos del Mioceno de Lisboa en las XL Jornadas de la SEP

Durante las XL Jornadas de la Sociedad Española de Paleontología celebradas en Aracena (Huelva), Rodrigo Figueiredo y colaboradores presentaron el enfoque sistemático preliminar de tres cráneos fósiles de Mysticeti procedentes del Mioceno de Lisboa. Estos fósiles son inéditos y pertenecen a la colección del Museu Geológico de Lisboa. El fósil más completo es también el ejemplar de Mysticeti de mayor tamaño jamás hallado en Portugal y el análisis filogenético lo sitúa en una posición basal del clado Balaenopteridae, constituyendo la primera evidencia de un Balaenopteridae fósil en Portugal. Este estudio se está llevando a cabo con la colaboración de la Faculdade de Ciências da Universidade de Lisboa, el Instituto Dom Luiz (IDL), el Grupo de Biología Evolutiva de la Universidad Nacional de Educación a Distancia (UNED), el Museu Nacional da Universidade Federal do Rio de Janeiro (MN-UFRJ), el Instituto de Biociências de la Universidade de São Paulo (IB-USP), el Department of Ecoscience de la Aarhus University, el Centro de Estudos do Ambiente e do Mar de la Universidade de Aveiro (CESAM) y el Grupo de Etnologia e Arquelogia da Lourinhã del Museu da Lourinhã (GEAL). El resumen es el siguiente:

The cetaceans represent one of the most intriguing groups of animals on Earth, whether it is for its origins, evolution or ecology. The Neogene sedimentary deposits of the Lower Tagus-Lower Sado Basin (Portugal) are rich in fossil marine mammals, and cetaceans are particularly well-recorded with many specimens being collected since the 19th century, including many cranial remains. The Portuguese cetacean fauna from the Neogene is diverse, especially during the Miocene with several identified taxa, including members of Mysticeti (Cetotheriidae) and Odontoceti (Ziphiidae, Kentriodontidae, Eurhinodelphinidae, Platanistidae). Only some specimens have been subject to detailed description, and a great number of these fossils still wait for a detailed anatomic and phylogenetic study. Here, we describe three mysticete skulls so far unpublished in detail deposited in the Museu Geológico (LNEG, Lisboa). One of the skulls was collected in Barreiro Dias Coelho in Marvila (Lisboa) from Division VIa of Cotter (MG 4962), Serravalian in age; and the two other skulls likely found in deposits of the Division VIc from Lisbon region, Serravalian–Tortonian in age (MG 25000 and MG 25002). MG 4962 is characterized by its size, being the largest mysticeti skull ever found from the Miocene of Portugal. This specimen is well-preserved, lacking the anterior portion of rostrum and the zygomatic process of the squamosal, being characterized by full-developed supraoccipital crest, transversely wide parabolic postglenoid process, and parallel sided nasals. MG 25000 and MG25002 are more incomplete. The former is distinct from MG 4962, being characterized by the presence of anteriorly restricted supraoccipital crest, triangular postglenoid processes, and the convergent nasals; the latter specimen displays long and parallel nasals, well-developed crest laterally to the ascending processes of the maxillae and a very pronounced supraoccipital crest. The phylogenetic position for these skulls is still uncertain, but the first results are recovering them within Balaenomorpha clade.

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