Ridgeview (Oligocene of the United States)

Also known as UNSM Dw-121

Where: Dawes County, Nebraska (42.8° N, 103.0° W: paleocoordinates 43.7° N, 96.4° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Arikaree Group, Geringian (30.8 - 26.3 Ma)

• "Gering Fm." according to Swisher 1982, but "near the base of the Arikaree Group" (Bailey 1992) and "early early Arikareean" (= Geringian) (Bailey 2004)

• group of beds-level stratigraphic resolution

Environment/lithology: coarse channel fill; unlithified conglomerate

• "attributed to flashy, upper flow regime sheet flooding in a broad, low relief, principal paleochannel" (Bailey 2004)
• "1 m thick sequence of fluvial, plane-bedded sand and fine epiclastic gravel, deposited above a coarse intraclast conglomerate... plane-bedded fine gravel facies" (Bailey 2004)

Size class: mesofossils

Reposited in the UNSM

Collection methods: bulk, sieve,

• 1000+ identifiable specimens (Bailey 1992)

•rock censused includes processed "gravel concentrate" and not the original sediment (Bailey 2004)

Primary reference: B. E. Bailey. 1992. Proceedings of the Nebraska Academy of Sciences 112 [J. Alroy/J. Alroy/J. Alroy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 17709: authorized by John Alroy, entered by John Alroy on 26.03.1995, edited by Jonathan Marcot

Creative Commons license: CC BY (attribution)

Taxonomic list

• "amphibians, reptiles, birds" and "fish" are present but not named (Bailey (2004)
 Rodentia - Cricetidae
Geringia mcgregori1 Macdonald 1970 mouse
Leidymys blacki1 Macdonald 1963 mouse
 Rodentia - Aplodontidae
cf. Prosciurus sp.1 Matthew 1903 mountain beaver
Meniscomys sp.1 Cope 1878 mountain beaver
Campestrallomys dawsonae1 Macdonald 1963 mountain beaver
 Rodentia - Sciuridae
Protospermophilus sp.1 Gazin 1930 squirrel
? Petauristodon sp.1 Engesser 1979 squirrel
Miospermophilus sp.1 Black 1963 squirrel
n. sp.
Nototamias sp.1 Pratt and Morgan 1989 squirrel
n. sp.
 Rodentia - Eomyidae
Leptodontomys douglassi2 Burke 1934 rodent
Metadjidaumo cf. hendryi1 Setoguchi 1978 rodent
 Rodentia - Geomyidae
Tenudomys ridgeviewensis n. sp.3 Korth and Branciforte 2007 pocket gopher
Tenudomys titanus3 Martin 1974 pocket gopher
 Rodentia - Florentiamyidae
Sanctimus cf. stouti3 Wahlert 1983 rodent
UNSM 130243
Sanctimus stuartae3 Macdonald 1970 rodent
Florentiamys tiptoni3 Macdonald 1970 rodent
 Rodentia - Heliscomyidae
Heliscomys sp.3 Cope 1873 rodent
UNSM 130501 - "UNSM 130501 cannot be referred to any of the other species of heliscomyid identified from the Ridgeview fauna based on the morphology of the lower premolar."
Heliscomys macdonaldi n. sp.3 Korth and Branciforte 2007 rodent
Tylionomys voorhiesi n. sp.3 Korth and Branciforte 2007 rodent
"Heliscomys woodi" = Tylionomys woodi4 McGrew 1941 rodent
 Rodentia - Heteromyidae
"Kirkomys schlaikjeri" = Proharrymys schlaikjeri1, "Proheteromys fedti" = Proharrymys fedti1, Proharrymys wahlerti n. sp.3
"Kirkomys schlaikjeri" = Proharrymys schlaikjeri1 Black 1961 rodent
"Proheteromys fedti" = Proharrymys fedti1 Macdonald 1963 rodent
Proharrymys wahlerti n. sp.3 Korth and Branciforte 2007 rodent
 Rodentia - Castoridae
cf. Agnotocastor sp.1 Stirton 1935 beaver
 Rodentia - Allomyidae
Downsimus chadwicki1 Macdonald 1970 rodent
cf. Allomys sp.1 Marsh 1877 rodent
 Lagomorpha - Leporidae
Palaeolagus philoi1 Dawson 1958 rabbit
Palaeolagus hypsodus1 Schlaikjer 1935 rabbit
Megalagus sp.1 Walker 1931 rabbit
 Lipotyphla - Erinaceidae
Ocajila makpiyahe1 Macdonald 1963 hedgehog
 Lipotyphla - Geolabididae
Centetodon cf. magnus1 Clark 1936 placental
 Lipotyphla - Talpidae
Scalopoides sp.4 Wilson 1960 mole
 Tribosphenida - Soricidae
Limnoecinae indet.1 Repenning 1967 shrew
n. gen. et sp.
 Tribosphenida - Heterosoricidae
Domnina sp.1 Cope 1873 placental
 Tribosphenida - Proscalopidae
"Oligoscalops whitmanensis" = Oligoscalops galbreathi1, Proscalops cf. miocaenus1
"Oligoscalops whitmanensis" = Oligoscalops galbreathi1 Reed 1956 placental
Proscalops cf. miocaenus1 Matthew 1901 placental
 Chiroptera - Vespertilionidae
"Myotis" sp.1 Kaup 1829 vesper bat
Oligomyotis sp.1 Galbreath 1962 vesper bat
a bat; ? Oligomyotis or ? Myotis sp.
 Ferae -
Carnivora indet. Bowditch 1821 carnivoran
 Macroscelidea - Amphilemuridae
Ankylodon annectens1 Patterson and McGrew 1937 elephant shrew
 Theriiformes - Peradectidae
Nanodelphys sp.1 McGrew 1937 metatherian
n. sp.
 Theriiformes - Herpetotheriidae
"Herpetotherium cf. fugax" = Peratherium fugax1
"Herpetotherium cf. fugax" = Peratherium fugax1 Cope 1873 marsupial