''Liolithax'' is an extinct genus of

dolphin A dolphin is an aquatic mammal in the cetacean clade Odontoceti (toothed whale). Dolphins belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), Pontopori ...

from the

Middle Miocene The Middle Miocene is a sub-epoch of the Miocene epoch (geology), epoch made up of two Stage (stratigraphy), stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene. The sub-epoch lasted from 15.97 ± 0. ...

(

Serravallian The Serravallian is, in the geologic timescale, an List of time periods, age or a stage (stratigraphy), stage in the middle Miocene epoch (geology), Epoch/series (stratigraphy), Series, which spans the time between 13.82 annum, Ma and 11.63 Ma (m ...

)

Temblor Formation The Temblor Formation is a geologic formation in California. It preserves fossils dating back from the Late Oligocene to the Middle Miocene of the Neogene period. It is notable for the famous Sharktooth Hill deposit (otherwise known as Ernst Quar ...

of California.

Taxonomy

''Liolithax kernensis'', described by

Remington Kellogg Arthur Remington Kellogg (5 October 1892 – 8 May 1969) was an American naturalist and a director of the United States National Museum. His work focused on marine mammals. Early life and career Kellogg was born in Davenport, Iowa, and quickly ...

on the basis of the periotic CAS 4370 in 1931, was considered the only species of the genus until Barnes (1978) reassigned ''"

Lophocetus ''Lophocetus'' ("crested whale") is an extinct genus of dolphin belonging to the clade Delphinida that is known from late Miocene (Tortonian) marine deposits in California and Maryland. Although usually placed in Kentriodontidae, recent studies h ...

" pappus'' to ''Liolithax'' based on similarities between the holotype periotic of ''L. kernensis'' and the periotic of ''L. pappus''. ''Liolithax'' was grouped in Kampholophinae with '' Kampholophos'' by Barnes (1978, 1985). The discovery of a skull from middle Miocene deposits in Baja California, Mexico cast doubt on the congenericity of ''"Lophocetus" pappus'' with the ''Liolithax'' type species by including a petrosal more similar to ''L. kernensis'' than to the petrosals included in the skulls of ''pappus''. In a 2008 SVPCA abstract, Lawrence Barnes and colleagues noted that the Baja California skull differed from ''"Lophocetus" pappus'' in having a smaller tooth diameter, a more slender rostrum, and smaller size. They classified ''Liolithax'' in Kentriodontinae while stressing that ''"Lophocetus" pappus'' is a lophocetine in need of a new generic name. The cladistic analysis of '' Brujadelphis'' by Lambert et al. (2017) recovered ''"Lophocetus" pappus'' (as ''Liolithax pappus'') as sister to

Lipotidae Lipotidae is a family of river dolphins containing the possibly extinct baiji of China and the fossil genus '' Parapontoporia'' from the Late Miocene and Pliocene of the Pacific coast of North America. The genus '' Prolipotes'', which is based on ...

, but did not test the phylogenetic relationships of ''Liolithax kernensis'' relative to Lipotidae, Iniidae, or other kentriodontids. The generic distinctness of ''"Lophocetus" pappus'' from the ''Liolithax'' type species was further confirmed by Godfrey and Lambert (2023), who erected the new genus '' Miminiacetus'' for ''L. pappus''.Godfrey, S. J., and Lambert, O. (2023). Miocene Toothed Whales (Odontoceti) from Calvert Cliffs, Atlantic Coastal Plain, USA. Smithsonian Contributions to Paleobiology. 107: 49–186. doi:10.5479/si.23847438.

References

{{Taxonbar, from=Q48996447 Kentriodontidae Miocene cetaceans Miocene mammals of North America Fossil taxa described in 1931