Fragmentary remains of Odontocetes (Cetacea, Mammalia) from the Miocene of the Lower Tagus Basin (Portugal)

Abstract

This first systematic account of the scarcely studied Miocene cetaceans from Portugal describes 17 previously unpublished odontocete specimens from the Lower Tagus Basin. In spite of their fragmentary nature, at least a familial assignment was accomplished for most, and some were even tentatively ascribed to known genera: the Physeteridae are represented only by isolated teeth of "Scaldicetus" type; the Platanistidae by a tympanic not definitely assigned to a particular genus; the Eurhinodelphinidae by a lumbar vertebra and an atlas, both only tentatively referred to this family; and the Kentriodontidae comprise the most diversified forms, including rostral and mandibular fragments of a kentriodontine close to Rudicetus, isolated teeth of another kentriodontine (cf. Macrokentriodon sp.), and rostral and mandibular fragments of an undetermined lophocetine. Some additional scrappy remains are listed only as Odontoceti indet. This small sample includes forms known both from the eastern and western North Atlantic, and the Mediterranean, thus reasserting the importance of the geographic position of Portugal as a link between all of these regions. Further systematic research may precise with which of them the Lower Tagus Basin Miocene odontocete fauna has a closer relationship, although, based on this preliminary data, the greater similarity seems at present to be with the western North Atlantic.

A Miocene sperm whale (Cetacea, Physeteroidea) tooth from Liessel (Noord-Brabant, the Netherlands)

“…In line with the conclusions of Bianucci & Landini (2006) and Lambert & Bianucci (2019), former Scaldicetus species outside of the type material of Scaldicetus caretti solely defined by large isolated teeth are referred to as Physeteroidea indet. The specimens described by Hasegawa et al (2001), Estevens & Antunes (2004), Kimura et al (2006) and Toscano et al (2013) all have been assigned to Scaldicetus, because these authors consider Scaldicetus to be a wastebasket genus for large enamel-capped physeteroid teeth or other less complete physeteroid fossils such as dentaries. We would suggest to formally refer to these and future isolated dental specimens as Physeteroidea indet.…”