Cetacea

Abstract

Clade PELAGICETI Uhen, 2008 DEFINITION. — Least inclusive monophyletic clade containing Neoceti and Basilosauridae. DIAGNOSIS. — Pelagicetes are middle Eocene to Recent cetaceans characterized by bony nares which are located posterior of P1 (Martínez-Cáceres et al. 2017), an occipital which is vertically or anteriorly inclined, anteroposteriorly shortened cervical vertebrae (Martínez-Cáceres et al. 2017), a broader scapula (Martínez-Cáceres et al. 2017; Gingerich et al. 2019) and the reduced size of the hindlimbs and pelvis (Gingerich et al. 1990, Martínez-Cáceres et al. 2017). Basal pelagicetes can also be recognized by the presence of multiple accessory denticles on the cheek teeth (Martínez-Cáceres et al. 2017), and lack of a third upper molar (Martínez-Cáceres et al. 2017, Muizon et al. 2019), though these features are lost in more derived taxa (Peredo et al. 2018). DISCUSSION Increased numbers of thoracic and lumbar vertebrae are often cited as synapomorphy of Pelagiceti (Martínez-Cáceres et al. 2017; Muizon et al. 2019), but some basal basilosaurids might show numbers of lumbar vertebrae similar to Protocetidae (Uhen 2014). Similarly, the derived protocetid Georgiacetus lacks a sacroiliac joint (Uhen 2008), another cited synapomorphy of pelagicetes (Martínez-Cáceres et al. 2017).

Authors 3

1. Jonas W. P. Hakkens

   Utrecht University

   Affiliation as printed

   Utrecht University, Faculty of Geosciences, Department of Earth Sciences, Princetonlaan 8 a, 3584 CB Utrecht (the Netherlands) j. w. p. hakkens @ students. uu. nl and jonashakkens @ gmail. com (corresponding author)

2. Jelle W. F. Reumer Aachen Faculty of Geosciences Department of Earth Sciences

   Utrecht University · Naturalis Biodiversity Center · Natural History Museum Rotterdam

   Affiliation as printed

   Utrecht University, Faculty of Geosciences, Department of Earth Sciences, Princetonlaan 8 a, 3584 CB Utrecht (the Netherlands) and Naturalis Biodiversity Center, Darwinweg 2, 2333 CR, Leiden (the Netherlands) and Natural History Museum Rotterdam, Westzeedijk 345, 3015 AA, Rotterdam (the Netherlands) j. w. f. reumer @ uu. nl

3. Anne S. Schulp Aachen Faculty of Geosciences Department of Earth Sciences

   Utrecht University · Naturalis Biodiversity Center · Teylers Museum

   Affiliation as printed

   Utrecht University, Faculty of Geosciences, Department of Earth Sciences, Princetonlaan 8 a, 3584 CB Utrecht (the Netherlands) and Naturalis Biodiversity Center, Darwinweg 2, 2333 CR, Leiden (the Netherlands) and Teylers Museum, Spaarne 16, 2011 CH, Haarlem (the Netherlands) a. s. schulp @ uu. nl