Cook Ranch (Oligocene of the United States)

Also known as MV 7721, MV 7722, MV 7723, MV 7726, MV 7734, MV 7745

Where: Beaverhead County, Montana (45.0° N, 112.8° W: paleocoordinates 46.6° N, 104.7° W)

• coordinate based on political unit

• small collection-level geographic resolution

When: upper Member (Sage Creek Formation), Orellan (33.9 - 33.3 Ma)

Environment/lithology: terrestrial

Primary reference: A. R. Tabrum, D. R. Prothero, and D. Garcia. 1996. Magnetostratigraphy and biostratigraphy of the Eocene-Oligocene transition, southwestern Montana. In D. R. Prothero and R. J. Emry (eds.), The Terrestrial Eocene-Oligocene Transition in North America 278-311 [J. Alroy/J. Alroy/J. Alroy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 17090: authorized by John Alroy, entered by John Alroy on 18.02.1993, edited by Clint Boyd and Jonathan Marcot

Creative Commons license: CC BY (attribution)

Taxonomic list

• originally described by Wood 1937
from two collections 10 m apart according to Wood, which matches discussion of Tabrum et al. 1996
stratigraphic nomenclature supersedes that of Hough 1955
 Rodentia - Cricetidae
Willeumys viduus1 Korth 1981 mouse
Scottimus sp. Wood 1937 mouse
Wilsoneumys focarius n. sp.1 Korth 2019 mouse
said to be new
Eumys cf. parvidens Wood 1937 mouse
Eumys aff. brachyodus Wood 1937 mouse
Eumys cf. cricetodontoides1 White 1954 mouse
"and/or E. cricetodontoides"
 Rodentia - Aplodontidae
Disallomys intermedius1 mountain beaver
Ninamys annectens1 Korth 1989 mountain beaver
Brachygaulus nicholsi n. sp.2 Korth and Tabrum 2011 mountain beaver
see Korth and Tabrum 2011
Brachygaulus nicholsi1 Korth and Tabrum 2011 mountain beaver
said to be new
Prosciurinae indet. Wilson 1949 mountain beaver
said to be a new genus and species
 Rodentia - Eomyidae
Paradjidaumo cf. trilophus1 Cope 1873 rodent
said to be new
Metadjidaumo woodi n. sp.1 Korth 2019 rodent
said to be new
Adjidaumo minimus Matthew 1903 rodent
 Rodentia - Heliscomyidae
Megaheliscomys mcgrewi1 Korth 1989 rodent
Heliscomys gregoryi Wood 1933 rodent
see also Wood 1933: "H. new species" of Wood 1937
 Rodentia - Castoridae
Agnotocastor cf. praetereadens1 Stirton 1935 beaver
 Rodentia - Ischyromyidae
Ischyromys sp. Leidy 1856 rodent
 Rodentia - Cylindrodontidae
? Sespemys sp. Wilson 1934 rodent
said to be new
Pseudocylindrodon sp. Burke 1935 rodent
said to be new
 Lagomorpha - Leporidae
Palaeolagus haydeni Leidy 1856 rabbit
see also Wood 1937
"Palaeolagus" cf. burkei Wood 1940 rabbit
Megalagus cf. turgidus Cope 1873 rabbit
 Lipotyphla - Erinaceidae
Ocajila cf. makpiyahe Macdonald 1963 hedgehog
 Lipotyphla - Talpidae
Talpidae indet. Fischer de Waldheim 1817 mole
two species, said to be new
 Perissodactyla - Hyracodontidae
? Hyracodon sp. Leidy 1856 odd-toed ungulate
see also Wood 1937
 Perissodactyla - Rhinocerotidae
Subhyracodon occidentalis3 Leidy 1850 rhinoceros
 Perissodactyla - Equidae
Mesohippus sp. Marsh 1875 anchitheriine horse
see also Wood 1937
 Tribosphenida - Heterosoricidae
Domnina aff. gradata Cope 1873 placental
 Tribosphenida - Proscalopidae
Oligoscalops sp. Reed 1961 placental
said to be new
 Tribosphenida - Apternodontidae
Oligoryctes cf. altitalonidus Clark 1936 placental
 Chiroptera - Vespertilionidae
Vespertilionidae indet. Gray 1821 vesper bat
a bat
 Carnivora - Canidae
Hesperocyon gregarius Cope 1873 canid
see also Wood 1937
 Carnivora -
Palaeogale sectoria Gervais 1848 carnivoran
 Ungulata - Merycoidodontidae
? Miniochoerus sp. Schultz and Falkenbach 1956 oreodont
"Merycoidodon cf. culbertsoni" = Merycoidodon (Merycoidodon) culbertsoni Leidy 1848 oreodont
 Ungulata - Camelidae
Poebrotherium sp. Leidy 1847 camel
 Ungulata - Anthracotheriidae
? Elomeryx sp. Marsh 1894 anthracothere
 Ungulata - Leptomerycidae
? Hendryomeryx sp. Black 1978 ruminant
Leptomeryx sp. Leidy 1853 ruminant
said to be new
Leptomeryx aff. evansi Leidy 1853 ruminant
see also Wood 1937
 Theriiformes - Peradectidae
Nanodelphys hunti Cope 1873 metatherian
 Theriiformes - Herpetotheriidae
"Herpetotherium fugax" = Peratherium fugax Cope 1873 marsupial
includes "H. sp." of Korth 1994; "Didelphidectes pumilis" of Hough 1961; and probably "Peratherium" of Wood 1937
Copedelphys cf. stevensoni Cope 1873 marsupial