Arner Ranch ant mounds (Eocene to of the United States)

Where: Nebraska (42.8° N, 103.6° W: paleocoordinates 44.0° N, 95.2° W)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: Big Cottonwood Creek Member (Chadron Formation), Late/Upper Chadronian to Late/Upper Chadronian (37.2 - 33.3 Ma)

• "All of the ant mounds sampled in this study rest upon rocks of the Big Cottonwood Creek Member. Detailed study of fossils previously collected in and around Toadstool Geological Park a few miles north of the present study area placed the stratigraphic position of the faunal transition between the Chadronian and Orellan biochrons at two meters above the UPW (±5 meters: Zanazzi et al., 2009). That same study determined that the late Chadronian (Ch4) to middle Chadronian (Ch3) subdivision transision occurred 18 meters below the UPW (±2 meters: Zanazzi et al., 2009), which is below the stratigraphic positions of all the ant mounds sampled in this study. Thus, the stratigraphic distribution of these ant mounds spans rocks that may preserve fossils deposited across the Chadronian-Orellan boundary, with the oldest fossils contributed from a late Chadronian fauna." (Korth et al. 2022)

• group of beds-level stratigraphic resolution

Environment/lithology: terrestrial; lithology not reported

Size classes: macrofossils, mesofossils

Collection methods: Repository: Museum of Geology at the South Dakota School of Mines and Technology, Rapid City, South Dakota, USA

Primary reference: W. W. Korth, C. A. Boyd, J. J. Person and D. Anderson. 2022. Fossil mammals from ant mounds situated on exposures of the Big Cottonwood Creek Member of the Chadron Formation (latest Eocene - Early Oligocene), Sioux County, Nebraska. Paludicola 13(4):191-344 [B. Allen/B. Allen]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 230806: authorized by Bethany Allen, entered by Bethany Allen on 21.07.2023

Creative Commons license: CC BY (attribution)

Taxonomic list

Mammalia
 Tribosphenida - Herpetotheriidae
Copedelphys stevensoni Cope 1873 marsupial
Herpetotherium fugax Cope 1873 marsupial
Herpetotherium valens Lambe 1908 marsupial
 Tribosphenida - Peradectidae
"Nanodelphys hunti" = Nanodelphys huntii
"Nanodelphys hunti" = Nanodelphys huntii Cope 1873 marsupial
 Cimolesta - Apatemyidae
Sinclairella dakotensis Jepsen 1934 eutherian
Apatemys sp. Marsh 1872 eutherian
 Chiroptera - Vespertilionidae
? Vespertilionidae indet. Gray 1821 vesper bat
 Macroscelidea - Amphilemuridae
Ankylodon cf. progressus Galbreath 1953 elephant shrew
 Primates - Omomyidae
Omomyidae indet. Gazin 1958 tarsier
 Lagomorpha - Leporidae
Palaeolagus haydeni Leidy 1856 rabbit
Approximate number of specimens
 Rodentia - Allomyidae
Haplomys galbreathi Tedrow and Korth 1997 rodent
 Rodentia - Aplodontidae
Altasciurus sp. Korth and Tabrum 2017 mountain beaver
Altasciurus clausulus Korth 2009 mountain beaver
Altasciurus relictus Cope 1873 mountain beaver
Altasciurus albiclivus Korth 1994 mountain beaver
Ansomys cyanotephrus Korth 2007 mountain beaver
Protansomys gulottai n. gen. n. sp. Korth et al. 2022 mountain beaver
SDSM 152447 (holotype), left dentary fragment with m1 and m2
Campestrallomys sp. Korth 1989 mountain beaver
Campestrallomys siouxensis Korth 1989 mountain beaver
Oropyctis sp. Korth 1989 mountain beaver
Oropyctis cf. pediasius Korth 1989 mountain beaver
Pseudallomys sp. Korth 1992 mountain beaver
Costepeiromys attasorus n. gen. n. sp. Korth et al. 2022 mountain beaver
SDSM 155705 (holotype), left m2
Pelycomys sp. Galbreath 1953 mountain beaver
 Rodentia - Sciuridae
Protosciurus mengi Black 1963 squirrel
Hesperopetes sp. Emry and Korth 2007 squirrel
Douglassciurus bjorki Korth 2014 squirrel
Oligospermophilus douglassi Korth 1981 squirrel
Cedromus modicus Korth et al. 2022 squirrel
 Rodentia - Cricetidae
Scottimus exiguus Wood 1937 rodent
Scottimus ambiguus Korth 1981 rodent
Scottimus lophatus Wood 1937 rodent
Eumys elegans Leidy 1856 rodent
Willeumys viduus Korth 1981 rodent
Wilsoneumys planidens Wilson 1949 rodent
 Rodentia - Ischyromyidae
Ischyromys brevidens n. sp. Korth et al. 2022 rodent
SDSM 155929, 156085 (syntypes), both right p4
 Rodentia - Cylindrodontidae
Cylindrodontidae indet. Miller and Gidley 1918 rodent
Cylindrodon nebraskensis Hough and Alf 1956 rodent
Siouxlindrodon sullivani n. gen. n. sp. Korth et al. 2022 rodent
SDSM 155559, 155576 (syntypes), left M1 or M1, left m1 or m2
 Rodentia - Eutypomyidae
Eutypomys cf. hibernodus Korth 2000 rodent
 Rodentia - Eomyidae
Aulolithomys vexilliames Korth and Emry 1997 rodent
Aulolithomys cf. bounites Black 1965 rodent
Metanoiamys paradoxus Emry and Korth 2012 rodent
Adjidaumo minimus Matthew 1903 rodent
Adjidaumo intermedius Korth 1989 rodent
Yoderimys massarae n. sp. Korth et al. 2022 rodent
SDSM 154961, 154967 (syntypes), right M1, left p4
Litoyoderimys grossus n. sp. Korth et al. 2022 rodent
SDSM 154969, 154970 (syntypes), right p4, right m1 or m2
Centimanomys major Galbreath 1955 rodent
Paradjidaumo cf. validus Korth 1980 rodent
Paradjidaumo patriciae n. sp. Korth et al. 2022 rodent
SDSM 150984 (holotype), right dentary with partial i1, p4-m3
 Rodentia - Heliscomyidae
Megaheliscomys mcgrewi Korth 1989 rodent
Heliscomys sp. Cope 1873 rodent
Heliscomys hatcheri Wood 1935 rodent
Heliscomys vetus Cope 1873 rodent
 Rodentia - Geomyidae
Tenudomys basilaris Korth 1989 pocket gopher
 Rodentia -
Diplolophus insolens Troxell 1923 rodent
Epeiromys sp. Korth 1989 rodent
 Rodentia - Florentiamyidae
Kirkomys miriamae n. sp. Korth et al. 2022 rodent
SDSM 151069 (holotype), left dentary fragment with p4
Ecclesimus tenuiceps Galbreath 1948 rodent
 Rodentia - Pipestoneomyidae
Pipestoneomys pattersoni Alf 1962 rodent
 Artiodactyla - Leptochoeridae
Stibarus cf. obtusilobus Cope 1873 even-toed ungulate
 Artiodactyla - Hypisodontidae
Hypisodus minimus Cope 1873 ruminant
 Artiodactyla - Leptomerycidae
? Leptomeryx sp. Leidy 1853 ruminant
Leptomeryx cf. exilis Cook 1934 ruminant
 Carnivora -
Ursoidea indet. Fischer de Waldheim 1817 carnivoran
 Carnivora - Subparictidae
Subparictis dakotensis Clark 1936 carnivoran
 Carnivora - Palaeogalidae
Palaeogale cf. minuta Gervais 1848 carnivoran
 Carnivora - Canidae
Hesperocyon gregarius Cope 1873 canid
Otarocyon macdonaldi Wang et al. 1999 bone-crushing dog
 Tribosphenida - Erinaceidae
Proterix minimus Korth 2009 hedgehog
Amphechinus sp. Aymard 1850 hedgehog
 Soricomorpha - Geolabididae
Centetodon wolffi Macdonald 1965 placental
Centetodon marginalis Cope 1873 placental
 Soricomorpha - Oligoryctidae
Oligoryctes tenutalonidus n. sp. Korth et al. 2022 placental
SDSM 150890 (holotype), dentary with m1-m3
Oligoryctes cf. cameronensis Hough 1956 placental
 Soricomorpha - Micropternodontidae
Micropternodus borealis Matthew 1903 placental
Micropternodus cf. montrosensis Ostrander 1983 placental
 Soricomorpha - Apternodontidae
Apternodus cf. major Asher et al. 2002 placental
 Soricomorpha - Soricidae
Noritrimylus compressus Galbreath 1953 shrew
Domnina gradata Cope 1873 shrew
 Soricomorpha - Proscalopidae
Oligoscalops galbreathi Reed 1956 placental
Proscalops sp. Matthew 1901 placental
 Leptictida - Leptictidae
Blacktops sp. Meehan and Martin 2010 eutherian
Leptictis dakotensis Leidy 1868 eutherian