Diaphorocetus poucheti (Cetacea, Odontoceti, Physeteroidea) from Patagonia, Argentina: one of the earliest sperm whales
Paolucci, F.; Buono, M.R.; Fernández, M.S.; Marx, F.G.; Cuitiño, J.I. (2020). Diaphorocetus poucheti (Cetacea, Odontoceti, Physeteroidea) from Patagonia, Argentina: one of the earliest sperm whales. J. Syst. Palaeontol. 18(4): 335-355. https://dx.doi.org/10.1080/14772019.2019.1605544 In: Journal of Systematic Palaeontology. Cambridge University Press: Cambridge. ISSN 1477-2019; e-ISSN 1478-0941, more |  |
| Keywords | Physeteroidea
Marine/Coastal | | Author keywords | Physeteroidea; Gaiman Formation; phylogeny; anatomy; body size; Miocene |
| Authors | | Top | - Paolucci, F.
- Buono, M.R.
- Fernández, M.S., more
| - Marx, F.G., more
- Cuitiño, J.I.
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| Abstract | Sperm whales (Physeteroidea) are the basal-most surviving lineage of odontocetes, represented today by just three highly specialized, deep-diving suction feeders. By contrast, extinct sperm whales were relatively diverse, reflecting a major Miocene diversification into various suction feeding and macroraptorial forms. The beginnings of this diversification, however, remain poorly understood. The Atlantic coast of South America provides a crucial window into early physeteroid evolution and has yielded some of the oldest species known from cranial material, Idiorophus patagonicus and Diaphorocetus poucheti – both of which are in need of re-description and phylogenetic reappraisal. Here, we re-examine Diaphorocetus in detail and, in light of its complex taxonomic history, declare it a nomen protectum. Phylogenetically, the species forms part of a polytomy including ‘Aulophyseter’ rionegresis and the two crown lineages (Physeteridae and Kogiidae) and demonstrates that facial asymmetry and a clearly defined supracranial basin have characterized this lineage for at least 20 Ma. With a total body length of 3.5–4 m, Diaphorocetus is one of the smallest physeteroids yet known. Its cranial morphology hints at an intermediate raptorial/suction feeding strategy and it has a moderately developed spermaceti organ and junk. |
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