<i>Koristocetus pescei</i> gen. et sp. nov., a diminutive sperm whale (Cetacea: Odontoceti: Kogiidae) from the late Miocene of Peru
Among odontocetes, members of the family Kogiidae (pygmy and dwarf sperm whales) are known as small-sized and in many respects enigmatic relatives of the great sperm whale <i>Physeter macrocephalus</i>. Most of the still scanty fossil record of Kogiidae is represented by isolated skul...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Pensoft Publishers
2017-12-01
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| Series: | Fossil Record |
| Online Access: | https://www.foss-rec.net/20/259/2017/fr-20-259-2017.pdf |
| Summary: | Among odontocetes, members of the family Kogiidae (pygmy and dwarf sperm
whales) are known as small-sized and in many respects enigmatic relatives of the great
sperm whale <i>Physeter macrocephalus</i>. Most of the still scanty fossil
record of Kogiidae is represented by isolated skulls and ear bones from
Neogene deposits of the Northern Hemisphere, with the significant exception
of <i>Scaphokogia</i>, a highly autapomorphic genus from late Miocene
deposits of the Pisco Formation exposed along the southern coast of Peru. Here we report on a
new fossil kogiid from Aguada de Lomas, a site where the late Miocene beds of
the Pisco Formation are exposed. This specimen consists of an almost complete
cranium representing a new taxon of Kogiidae: <i>Koristocetus pescei</i>
gen. et sp. nov. <i>Koristocetus</i> mainly differs from extant
<i>Kogia</i> spp. by displaying a larger temporal fossa and
well-individualized dental alveoli on the upper jaws. Coupled with a
relatively elongated rostrum, these characters suggest that
<i>Koristocetus</i> retained some degree of raptorial feeding abilities,
contrasting with the strong suction feeding specialization seen in Recent
kogiids. Our phylogenetic analysis recognizes <i>Koristocetus</i> as the
earliest branching member of the subfamily Kogiinae. Interestingly,
<i>Koristocetus</i> shared the southern coast of present-day Peru with
members of the genus <i>Scaphokogia</i>, whose unique convex rostrum and
unusual neurocranial morphology seemingly indicate a peculiar foraging
specialization that has still to be understood. In conclusion,
<i>Koristocetus</i> evokes a long history of high diversity, morphological
disparity, and sympatric habits in fossil kogiids, thus suggesting that our
comprehension of the evolutionary history of pygmy and dwarf sperm whales is
still far from being exhaustive. |
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| ISSN: | 2193-0066 2193-0074 |