Takikawa sea cow

The Takikawa sea cow (Hydrodamalis spissa) is an extinct herbivorous marine mammal of the Late Pliocene which was closely related to the recently extinct Steller's sea cow (H. gigas). In 1988, fossils of sea cows were discovered in Hokkaido and were originally assigned to the Takikawa sea cow,^[1] a newly described species, even though this taxon is thought of by some scientists as a synonym of the Cuesta sea cow (H. cuestae). It is uncertain whether or not the Takikawa sea cow was simply a local variant of the Cuesta sea cow or a completely separate lineage.^[1][2][3] However, the Steller's sea cow and Takikawa sea cow share more morphological similarities than the Takikawa sea cow and Cuesta sea cow.^[4]

Relations within Hydrodamalinae

Sirenia †Dusisiren reinharti †Dusisiren jordani †Dusisiren dewana †Dusisiren takasatensis †Hydrodamalis cuestae †Hydrodamalis spissa †Hydrodamalis gigas

Based on a 2004 study by Hitoshi Furusawa[4]

Takikawa sea cow Temporal range: Late Pliocene 3.6–2.6 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Reconstructed skeleton, Sapporo
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Sirenia
Family:	Dugongidae
Genus:	†Hydrodamalis
Species:	†H. spissa
Binomial name
†Hydrodamalis spissa Furusawa, 1988
Synonyms
?†H. cuestae Domning, 1978

References

1. Furusawa, Hitoshi (1988). A new species of hydrodamaline Sirenia from Hokkaido, Japan. Takikawa Museum of Art and Natural History. pp. 1–73.
2. Marsh, Helene; O'Shea, Thomas J.; Reynolds III, John E. (2011). "Steller's sea cow: discovery, biology and exploitation of a relict giant sirenian". Ecology and Conservation of the Sirenia: Dugongs and Manatees. New York: Cambridge University Press. pp. 18–35. ISBN 978-0-521-88828-8.
3. Furusawa, Hitoshi (1990). "Discovery and significance of the Takikawa sea cow (Hydrodamalis spissa) from Numata-cho, Uryu-gun, Hokkaido, Japan". Earth Science. 44 (4): 224–228.
4. Furusawa, Hitoshi (2004). "A phylogeny of the North Pacific Sirenia (Dugongidae: Hydrodamalinae) based on a comparative study of endocranial casts". Paleontological Research. 8 (2): 91–98. doi:10.2517/prpsj.8.91.