El Gramal: Barstovian, Mexico

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Mammalia - Perissodactyla - Equidae
Merychippus sp. Leidy 1856
"sensu lato"
Mammalia - Camelidae
Camelidae indet. Gray 1821
Mammalia - Protoceratidae
? Protoceratidae indet. Marsh 1891
Mammalia - Proboscidea - Gomphotheriidae
Gomphotherium sp. Burmeister 1837
see common names

Geography
Country:Mexico State/province:Oaxaca
Coordinates: 16.6° North, 96.1° West (view map)
Paleocoordinates:17.1° North, 93.3° West
Basis of coordinate:estimated from map
Geographic resolution:outcrop
Time
Period:Neogene Epoch:Miocene
10 m.y. bin:Cenozoic 5
*Period:Tertiary
Key time interval:Barstovian
Age range of interval:15.97000 - 13.60000 m.y. ago
* legacy (obsolete) database fields
Stratigraphy
Formation:El Camarón
Stratigraphic resolution:member
Stratigraphy comments: formation "is estimated between 200 and 250 m... The fossil mammals occurred in the lower member (usually the lower part), and were collected at several sites [seven shown on map]... from a zone ~30 m thick at the most"; it intertongues with the Yautepec Tuff, dated at 15.0 +/- 0.8 to 16.7+/- 0.71 by K-Ar (Bravo-Cuevas and Ferrusquía-Villafranca 2006)
Lithology and environment
Primary lithology:tuffaceous poorly lithified siltstone
Secondary lithology:tuffaceous poorly lithified sandstone
Lithology description: formation is "Friable to moderately indurated tuffaceous siltstone, sandstone and conglomerate; lower part [yielding the fossils] is finer grained and thinly bedded" (Bravo-Cuevas and Ferrusquía-Villafranca 2006)
Environment:terrestrial indet.
Taphonomy
Modes of preservation:body
Size of fossils:macrofossils
Collection methods and comments
Collection methods:field collection
Reason for describing collection:general faunal/floral analysis
Taxonomic list comments:overlies tuff dated by K-Ar at 14.96 +/- 0.85 Ma
Metadata
Also known as:Nejapa
Database number:18724
Authorizer:J. Alroy Enterer:J. Alroy
Modifier:J. Alroy Research group:vertebrate
Created:1993-02-18 00:00:00 Last modified:2007-01-14 17:11:10
Access level:the public Released:1993-02-18 00:00:00
Creative Commons license:CC BY
Reference information

Primary reference:

1483. I. Ferrusquia-Villafranca. 1990. Biostratigraphy of the Mexican Continental Miocene: Part I, Introduction and the Northwestern and Central Faunas. Part II, The Southeastern (Oaxacan) Faunas. Part III, The Southeasternmost (Chiapasan) Fauna and Concluding Remarks On the Discussed Vertebrate Record. Paleontologia Mexicana 56:1-149 [J. Alroy/J. Alroy/J. Marcot]

Secondary references:

19645 V. M. Bravo-Cuevas and I. Ferrusquía-Villafranca. 2006. Merychippus (Mammalia, Perissodactyla, Equidae) from the Middle Miocene of state of Oaxaca, southeastern Mexico. Géobios 39:771-784 [J. Alroy/J. Alroy]