Rancho Viejo ( of Mexico)

Also known as Arrastracabllos; Gto-4; GTO-5 (Miller Place); GTO-5A; GTO-5B; Gto-6; Gto. 6; GTO-6; GTO-14 (Cuesta Blanca); Gto-18; GTO-31 (Pajaro Grande); GTO-33 (Pork Chop); Gto-45; Tren Plano

Where: Guanajuato, Mexico (21.0° N, 100.8° W: paleocoordinates 21.1° N, 100.2° W)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: Rancho Viejo Beds Formation, Blancan (4.9 - 1.8 Ma)

• dated at 3.6 Ma by Kowallis et al. 1986 using FT on zircon; this is the younger of two modes, the other being at 30.7 Ma

•this date is superseded by paleomag and an Ar/Ar date of 3.36 +/- 0.04 Ma reported by Flynn et al. 2005, which show that all of chron C2An.3n and the neighboring reversed chrons are spanned by the lengthy Blancan fossiliferous interval

•overlies Coecillo and Arroyo Tepalcates

• member-level stratigraphic resolution

Environment/lithology: "floodplain"; brown, yellow, silty, sandy claystone and volcaniclastic ash

• "interpreted as floodplain deposits" (Jimenez-Hidalgo et al. 2004)
• "yellow brown sandy and silty clays with some lenses of volcanic ash and sand" (Jimenez-Hidalgo et al. 2004)

Size class: macrofossils

Primary reference: W. E. Miller and O. Carranza-Castaneda. 1984. Late Cenozoic Mammals from Central Mexico. Journal of Vertebrate Paleontology 4(2):216-236 [J. Alroy/J. Alroy/J. Ju]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 20077: authorized by John Alroy, entered by John Alroy on 18.02.1993, edited by Jonathan Marcot

Creative Commons license: CC BY (attribution)

Taxonomic list

• list of Miller and Carranza 1998a is poorly researched
 Rodentia - Sciuridae
Paenemarmota sp. Hibbard and Schultz 1948 squirrel
omitted from Gto. 6 list of Miller and Carranza 1998a
Spermophilus matachicensis8 Wilson 1949 ground squirrel
 Rodentia - Hydrochoeridae
"Neochoerus dichroplax" = Phugatherium dichroplax2
"Neochoerus dichroplax" = Phugatherium dichroplax2 Ahearn and Lance 1980 caviomorph
 Rodentia - Caviidae
Neochoerus sp.2 Hay 1926 caviomorph
 Lagomorpha - Leporidae
Paranotolagus complicatus n. sp. Miller and Carranza-Castaneda 1982 rabbit
see Miller and Carranza 1982
Notolagus velox9 Wilson 1937 rabbit
presumably "Nekrolagus sp." of Miller and Carranza 1998a
Pewelagus mexicanus1 Miller and Carranza-Castaneda 1982 rabbit
Aluralagus cf. bensonensis10 Gazin 1942 rabbit
 Perissodactyla - Equidae
Nannippus peninsulatus Cope 1885 hipparionine horse
"Equus simplicidens" = Equus (Dolichohippus) simplicidens2 Cope 1892 horse
 Carnivora - Ursidae
Ursidae indet. Gray 1825 bear
 Carnivora - Mustelidae
Mustelidae indet. Fischer 1817 mustelid carnivore
 Carnivora - Canidae
Borophagus diversidens8 Cope 1892 bone-crushing dog
 Carnivora - Felidae
Machairodus sp.4 Kaup 1833 cat
Miracinonyx cf. studeri3 Savage 1960 American cheetah
 Xenarthra - Mylodontidae
"Paramylodon garbanii" = Glossotherium garbanii1
"Paramylodon garbanii" = Glossotherium garbanii1 Montellano and Carranza-Castaneda 1981 edentate
 Xenarthra - Glyptodontidae
"Glyptotherium ? arizonae" = Glyptotherium texanum8
"Glyptotherium ? arizonae" = Glyptotherium texanum8 Osborn 1903 glyptodon
 Proboscidea - Gomphotheriidae
Gomphotheriidae indet. Hay 1922 gomphothere
 Ungulata - Tayassuidae
Platygonus sp.8 Leconte 1848 peccary
 Ungulata - Camelidae
Megatylopus sp.6 Matthew and Cook 1909 camel
Camelops sp.6 Leidy 1854 camel
Blancocamelus meadei6 Dalquest 1975 camel
"Hemiauchenia blancoensis" = Hemiauchenia macrocephala5 Cope 1893 camel
Hemiauchenia gracilis6 Meachen 2005 camel
 Ungulata - Antilocapridae
Capromeryx tauntonensis7 Morgan and Morgan 1995 pronghorn
"Rancho Viejo beds, about 12 km northeast of the city of San Miguel de Allende"
Hexobelomeryx ? fricki8 Furlong 1941 pronghorn