Horsetail Creek (Eocene of the United States)

Also known as Horse Tail Creek

Where: Logan County, Colorado (40.8° N, 103.1° W: paleocoordinates 42.1° N, 94.6° W)

• coordinate based on political unit

When: Horsetail Creek Member (White River Formation), Chadronian (37.2 - 33.9 Ma)

Environment/lithology: terrestrial; lithology not reported

Size class: macrofossils

Primary reference: E. D. Cope. 1875. Report on the vertebrate paleontology of Colorado. Annual Report of the United States Geological and Geographical Survey of the Territories 1873:427-533 [M. Carrano/M. Carrano/M. Carrano]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 16977: authorized by John Alroy, entered by John Alroy on 18.02.1993, edited by Jonathan Marcot, Terri Cleary and Evangelos Vlachos

Creative Commons license: CC BY (attribution)

Taxonomic list

• entire member is of reversed polarity: Prothero 1996c
"Cylindrodon fontis": Galbreath 1969 see discussion of this species by Emry and Korth 1996a; Molly and Mabel loc., Section 36 loc., and Shable Butte loc.

"Caenopus mitis" is of uncertain provenance

"Archaeotherium ramosus" and "A. potens" are of uncertain provenance

•list excludes Trigonias Quarry (see)

Reptilia
 Testudines - Pantestudinidae
"Testudo ligonius n. sp." = Stylemys nebrascensis2, "Testudo amphithorax n. sp." = Stylemys nebrascensis2, Testudo quadratus n. sp.3, "Testudo laticuneus n. sp." = Gopherus laticuneus2
"Testudo ligonius n. sp." = Stylemys nebrascensis2 Leidy 1851 turtle
"Testudo amphithorax n. sp." = Stylemys nebrascensis2 Leidy 1851 turtle
Testudo quadratus n. sp.3 Cope 1884 turtle
AMNH 1149 (holotype), a fragmentary epiplastron and partial nuchal (Hay 1908, figs. 532, 533)
"Testudo laticuneus n. sp." = Gopherus laticuneus2 Cope 1873 gopher tortoise
 Testudines -
Testudo culbratus n. sp.2 Cope 1873 turtle
 Squamata -
Cremastosaurus rhambastes n. sp.7 Cope 1884 lizard
AMNH 1606 (holotype), seven dorsal vertebrae
 Squamata - Rhineuridae
"Rhineura coloradoensis n. sp." = Rhineura hatcherii7
"Rhineura coloradoensis n. sp." = Rhineura hatcherii7 Baur 1893 worm lizard
AMNH 1607 (holotype), three and a half articulated median dorsal vertebrae
Mammalia
 Rodentia - Cricetidae
Eumys sp.11 Leidy 1856 mouse
new specimen, provenance considered certain based on association with titanothere
 Rodentia - Eomyidae
Paradjidaumo trilophus5 Cope 1873 rodent
Centimanomys major6 Galbreath 1955 rodent
Centimanomys galbreathi12 Martin and Ostrander 1986 rodent
Adjidaumo cf. minimus15 Matthew 1903 rodent
not A. minutus, contra Wood 1969: "A. small sp." of Galbreath; presumably "A. minutus" of Wahlert 1978 from "near Trigonias Quarry, Weld Co., Colorado, ?Chadronian"
 Rodentia - Ischyromyidae
Pelycomys rugosus5 Galbreath 1953 rodent
Ischyromys typus1 Leidy 1856 rodent
Ischyromys cf. veterior1 Matthew 1903 rodent
 Rodentia - Cylindrodontidae
Pseudocylindrodon cf. neglectus15, "Cylindrodon galbreathi n. sp." = Cylindrodon nebraskensis5
"Cylindrodon galbreathi n. sp." = Cylindrodon nebraskensis5 Hough and Alf 1956 rodent
 Lagomorpha - Leporidae
Palaeolagus sp.10 Leidy 1856 rabbit
 Perissodactyla - Brontotheriidae
Brontotheriidae indet.1 Marsh 1873 brontothere
 Perissodactyla - Hyracodontidae
Hyracodon sp.5 Leidy 1856 odd-toed ungulate
 Perissodactyla - Rhinocerotidae
"Aceratherium mite n. sp." = Subhyracodon mitis Cope 1875 rhinoceros
Penetrigonias dakotensis13 Peterson 1920 rhinoceros
Trigonias osborni5 Lucas 1900 rhinoceros
two new specimens
 Perissodactyla - Equidae
Mesohippus bairdi1 Leidy 1850 anchitheriine horse
 Tribosphenida - Apternodontidae
Apternodus iliffensis5 Galbreath 1953 placental
 Carnivora - Ursidae
Parictis dakotensis5 Clark 1936 bear
confirmed by Baskin and Tedford 1996
 Carnivora - Amphicyonidae
Brachyrhynchocyon sp.9 Scott and Jepsen 1936 bear-dog
"Chadronian... Cedar Creek area, Logan/Weld Cos."
 Carnivora - Canidae
Hesperocyon gregarius1 Cope 1873 canid
 Carnivora - Nimravidae
Dinictis sp.5 Leidy 1854 false sabre-tooth
 Theriiformes - Herpetotheriidae
Peratherium fugax5 Cope 1873 marsupial
 Artiodactyla - Tayassuidae
Tayassuidae indet.16 Palmer 1897 peccary
 Artiodactyla - Leptochoeridae
Stibarus quadricuspis4 Hatcher 1901 even-toed ungulate
Stibarus obtusilobus5 Cope 1873 even-toed ungulate
 Artiodactyla - Entelodontidae
Archaeotherium mortoni5, "Archaeotherium ramosus" = Pelonax ramosus5, "Archaeotherium potens" = Pelonax potens5
Archaeotherium mortoni5 Leidy 1850 even-toed ungulate
includes "A. crassum"; latter is said by Troxell 1920c to be from "Probably Cedar Creek beds... near Gerry's Ranch"; assignment to Horsetail Creek by Galbreath based on co-occurrence with titanotheres
"Archaeotherium ramosus" = Pelonax ramosus5 Cope 1874 even-toed ungulate
"Occurrence probably here rather than in the Cedar Creek member, but not yet demonstrated"
"Archaeotherium potens" = Pelonax potens5 Marsh 1893 even-toed ungulate
"Occurrence probably here rather than in the Cedar Creek member, but not yet demonstrated"
 Artiodactyla - Camelidae
Poebrotherium eximium8 Hay 1902 camel
 Artiodactyla - Oromerycidae
Eotylopus sp.5 Matthew 1910 even-toed ungulate
 Artiodactyla - Merycoidodontidae
"Merycoidodon gracilis" = Miniochoerus gracilis5, "Merycoidodon culbertsoni" = Merycoidodon culbertsoni5, "Genetochoerus periculorum n. gen. n. sp." = Merycoidodon culbertsoni14
"Merycoidodon gracilis" = Miniochoerus gracilis5 Leidy 1851 oreodont
"Merycoidodon culbertsoni" = Merycoidodon culbertsoni5 Leidy 1848 oreodont
"Genetochoerus periculorum n. gen. n. sp." = Merycoidodon culbertsoni14 Leidy 1848 oreodont
AM 6397 (holotype)
 Artiodactyla - Anthracotheriidae
Anthracotheriidae indet.5 Leidy 1869 anthracothere
 Artiodactyla - Hypisodontidae
Hypisodus sp.5 Cope 1873 ruminant
form A
 Artiodactyla - Leptomerycidae
Leptomeryx evansi5 Leidy 1853 ruminant
Leptomeryx esulcatus5 Cope 1889 ruminant