Rancho El Ocote (Medial): Late/Upper Hemphillian, Mexico
collected by O. Carranza-Castañeda, B. Slaughter, C. McKinney

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Mammalia - Rodentia - Sciuridae
Paenemarmota sp. Hibbard and Schultz 1948
includes "P. mexicana" of Dalquest and Mooser 1980a
Mammalia - Rodentia - Cricetidae
Cricetidae indet. Fischer von Waldheim 1817
Carranza-Castañeda and Walton 1992
section GTO 2a
Prosigmodon sp. Jacobs and Lindsay 1981
(6 measurements)
    = Prosigmodon ferrusquiai n. sp. Carranza-Castañeda and Walton 1992
Carranza-Castañeda and Walton 1992
sections GTO 2a and 2b
Prosigmodon oroscoi Jacobs and Lindsay 1981
Carranza-Castañeda and Walton 1992
sections GTO 2a and 2b (6 measurements)
Prosigmodon chihuahuensis Lindsay and Jacobs 1985
Carranza-Castañeda and Walton 1992
section GTO 2b (1 measurement)
Baiomys kolbi Hibbard 1952
Carranza-Castañeda and Walton 1992
sections GTO 2a and 2b (1 measurement)
Neotoma (Paraneotoma) sp. Hibbard 1967
Carranza-Castañeda and Walton 1992
possibly new: section GTO 2a
Neotoma (Paraneotoma) cf. sawrockensis Hibbard 1967
Carranza-Castañeda and Walton 1992
sections GTO 2a and 2b (4 measurements)
Calomys sp. (Waterhouse 1837)
(5 measurements)
    = Calomys (Bensonomys) baskini Lindsay and Jacobs 1985
Carranza-Castañeda and Walton 1992
sections GTO 2a and 2b
Calomys (Bensonomys) winklerorum n. sp. Carranza-Castañeda and Walton 1992
Carranza-Castañeda and Walton 1992
sections GTO 2a and 2b (4 measurements)
Calomys (Bensonomys) elachys (Lindsay and Jacobs 1985)
Carranza-Castañeda and Walton 1992
sections GTO 2a and 2b (1 measurement)
Mammalia - Lagomorpha - Leporidae
Hypolagus sp. Dice 1917
    = Hypolagus cf. ringoldensis Gustafson 1978
White 1988
said to be similar to H. oregonensis and H. ringoldensis by Miller and Carranza 1982
Notolagus sp. Wilson 1937
    = Notolagus velox Wilson 1937
White 1991
"N. cf. velox" of Miller and Carranza 1982 DUPLICATE REF 3633 or 3634
Mammalia - Perissodactyla - Equidae
Dinohippus mexicanus (Lance 1950)
original and current combination Pliohippus (Pliohippus) mexicanus
Astrohippus stockii (Lance 1950)
original and current combination Pliohippus (Astrohippus) stockii
Mammalia - Tayassuidae
Platygonus sp. Leconte 1848
Mammalia - Camelidae
Megatylopus sp. (Matthew and Cook 1909)
original and current combination Pliauchenia (Megatylopus)
Hemiauchenia vera (Matthew 1909)
Montellano 1989
recombined as Pleiolama vera
probably includes "H. sp."; may also include "Palaeolama guanajuatensis," although this is much smaller
Mammalia - Mylodontidae
cf. Glossotherium sp. Owen 1840
possibly includes "Pampatherium" of Carranza et al. 2000 from "4.7 Ma" level
Mammalia - Proboscidea - Gomphotheriidae
cf. Stegomastodon sp. Pohlig 1912
see common names

Geography
Country:Mexico State/province:Guanajuato
Coordinates: 21.2° North, 100.7° West (view map)
Paleocoordinates:21.5° North, 99.1° West
Basis of coordinate:based on nearby landmark
Geographic resolution:outcrop
Time
Period:Neogene
10 m.y. bin:Cenozoic 6
*Period:Tertiary *Epoch:Miocene
Key time interval:Late/Upper Hemphillian
Age range of interval:10.30000 - 4.90000 m.y. ago
* legacy (obsolete) database fields
Stratigraphy
Formation:Rancho Viejo Beds
Local section:Ocote Local bed:2
Local order:bottom to top
Stratigraphic resolution:group of beds
Stratigraphy comments: level dated at 4.6 Ma FT on zircon; according to Kowallis et al. 1986, this is the youngest of three modes, the others being at 11.0 and 24.5 Ma
this date is superseded by an Ar/Ar date of 4.74 +/- 0.14 Ma reported by Flynn et al. 2005 for an ash immediately overlying the fauna
unit is "2-3 m thick, lies disconformably on the lower unit" (Carranza-Castañeda and Walton 1992)
Lithology and environment
Primary lithology:tuffaceous,gray,white claystone
Secondary lithology:"cross stratification" sandstone
Lithology description: "gray and white volcanic ash and clay. Crossbedded sand occurs in rare, poorly defined lenses" (Carranza-Castañeda and Walton 1992)
Environment:"channel"
Geology comments: at GTO 2a the unit is "channeled, muddy clay" and at GTO 2c is is "incised by a sand-mud channel"
Taphonomy
Modes of preservation:body
Size of fossils:macrofossils,mesofossils
Preservation of anatomical detail:good
Abundance in sediment:abundant
Disassociated minor elements:many
Collection methods and comments
Collection methods:bulk,sieve
Reason for describing collection:general faunal/floral analysis
Collectors:O. Carranza-Castañeda, B. Slaughter, C. McKinney
Collection method comments: microfossils collected by "screenwashing" (Carranza-Castañeda and Walton 1992)
Metadata
Also known as:Arroyo de la Carreta; White layer
Database number:18738
Authorizer:J. Alroy Enterer:J. Alroy
Modifier:P. Mannion Research group:vertebrate
Created:1995-03-26 00:00:00 Last modified:2020-08-11 08:55:21
Access level:the public Released:1995-03-26 00:00:00
Creative Commons license:CC BY
Reference information

Primary reference:

1175. O. Carranza-Castaneda. 1989. Rinocerontes de la fauna local Rancho el Ocote, Mioceno Tardio (Hemfiliano tardio) de estado de Guanajuato. Universidad Nacional Autónoma de México, Instituto de Geológia, Revista, Publicación Especial 8(1):88-99 [J. Alroy/J. Alroy/M. Uhen]

Secondary references:

6294 J. Alroy. 2002. Synonymies and reidentifications of North American fossil mammals. [J. Alroy/J. Alroy/M. Kouvari]
25387 O. Carranza-Castañeda and A. H. Walton. 1992. Cricetid rodents from the Rancho El Ocote fauna, late Hemphillian (Pliocene), State of Guanajuato. Universidad Nacional Autónoma de México, Instituto de Geologia, Revista 10(1):71-93 [J. Alroy/J. Alroy]
23536 J. J. Flynn, B. J. Kowallis, C. Nuñez, O. Carranza-Castañeda, W. E. Miller, C. C. Swisher, III, and E. Lindsay. 2005. Geochronology of Hemphillian-Blancan aged strata, Guanajuato, Mexico, and implications for the timing of the Great American Biotic Interchange. Journal of Geology 113:287-307 [J. Alroy/J. Alroy/M. Uhen]
6255 M. Montellano. 1989. Pliocene Camelidae of Rancho El Ocote, central Mexico. Journal of Mammalogy 70(2):359-369 [J. Alroy/J. Alroy/J. Alroy]
3632 J. A. White. 1988. The Archaeolaginae (Mammalia, Lagomorpha) of North America, Excluding Archaeolagus and Panolax. Journal of Vertebrate Paleontology 7(4):425-450 [J. Alroy/J. Alroy/J. Ju]
3633 J. A. White. 1991. North American Leporinae (Mammalia: Lagomorpha) from late Miocene (Clarendonian) to latest Pliocene (Blancan). Journal of Vertebrate Paleontology 11(1):67-89 [J. Alroy/J. Alroy/J. Alroy]