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| Nihohae matakoi Coste, Fordyce & Loch, 2023 |
Abstract
All extant toothed whales (Cetacea, Odontoceti) are aquatic mammals with homodont dentitions. Fossil evidence from the late Oligocene suggests a greater diversity of tooth forms among odontocetes, including heterodont species with a variety of tooth shapes and orientations. A new fossil dolphin from the late Oligocene of New Zealand, Nihohae matakoi gen. et sp. nov., consisting of a near complete skull, earbones, dentition and some postcranial material, represents this diverse dentition. Several preserved teeth are horizontally procumbent, including all incisors and canines. These tusk-like teeth suggest adaptive advantages for horizontally procumbent teeth in basal dolphins. Phylogenetic analysis places Nihohae among the poorly constrained basal waipatiid group, many with similarly procumbent teeth. Features of N. matakoi such as its dorsoventrally flattened and long rostrum, long mandibular symphysis, unfused cervical vertebrae, lack of attritional or occlusal wear on the teeth and thin enamel cover suggest the rostrum and horizontally procumbent teeth were used to injure and stun prey though swift lateral head movements, a feeding mode that did not persist in extant odontocetes.
Keywords: functional morphology, dolphin, palaeoecology, evolution, evolution, phylogeny
Subjects
Systematic palaeontology
CETACEA Brisson, 1762
ODONTOCETI Flower, 1867
Nihohae matakoi, gen. et sp. nov.
Etymology:
Genus - From the Māori language, ‘Niho’ for teeth and ‘Hae’ for slashing, in reference to possible use of the teeth.
Species - From the Māori language, ‘Mata’ for face/point and ‘Koi’ for sharp, in reference to the long, flat and thin rostrum ending in pointed sharp teeth.
Pronunciation guide – nee-ho-ha-eh ma-ta-koy
Ambre Coste, R. Ewan Fordyce and Carolina Loch. 2023. A New Dolphin with Tusk-like Teeth from the late Oligocene of New Zealand indicates Evolution of Novel Feeding Strategies. Proc. R. Soc. B. 29020230873. DOI: 10.1098/rspb.2023.0873
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