E. stockeyae Montellano-Ballesteros et al., 2021[2]
E. superstes Granger, 1915
Ectocion (sometimes Ectocyon) is an extinct
genus of
placental mammals of the family
Phenacodontidae. The genus was earlier classified as Gidleyina (Simpson 1935) and Prosthecion (Patterson and West 1973)[3] It reached 6 to 12 kg and was similar in size and morphology to Copecion. Both these herbivorous ungulates likely occupied similar ecological niches.[4]
Paleocene specimens of these hoofed, ground-dwelling herbivores have been found in
Canada (Alberta, Saskatchewan) and the United States (Colorado, Montana, North Dakota, and Wyoming).
Eocene specimens have been found in
Mexico and the
United States (Colorado, Mississippi, Wyoming).[3]
One of the dramatic effects of the
Paleocene–Eocene Thermal Maximum (PETM) was some animals evolving smaller bodies. Fossilized Ectocion jaw bones show that this genus was smaller during (E. parvus, 55.5
mya) the PETM than its relatives before (E. osbornianus, 55.6 mya) and after (E. osbornianus, 55.3 mya) the brief climatic peak period.[5]
^Montellano-Ballesteros, M.; Fox, R. C.; Scott, C. S. (2021). "A new, "dwarfed" species of the phenacodontid "condylarth" Ectocion from the late Paleocene of Alberta, Canada, and its implications". Canadian Journal of Earth Sciences. 58 (11): 1155–1169.
Bibcode:
2021CaJES..58.1155M.
doi:
10.1139/cjes-2019-0234.
hdl:1807/107869.