Lomas las Tetas de Cabra (Eocene of Mexico)

Also known as East Hill Cairn; Younger World; Too Much Hot; Mutant Hill; Lil' Buddy; Quieter Locality; Windy Gap; Manly Man; Marsupial Hill; Two Years; The H-World; Generic Locality; Danger Bird; Eeyi-Ha; The Way; Occidental Buttes; SB Hill; Slump Hill; Punta Prieta; assorted AMNH and IGM localities

Where: Baja California, Mexico (28.7° N, 114.1° W: paleocoordinates 31.1° N, 97.0° W)

• coordinate stated in text

• outcrop-level geographic resolution

When: Las Tetas de Cabra Formation, Wasatchian (55.8 - 50.3 Ma)

• member-level stratigraphic resolution

Environment/lithology: fluvial-lacustrine; brown, red, white sandstone and red, argillaceous siltstone

• "a fluvial, freshwater system of streams and ponds... less than 8 km inland"
• brown, red, and white sandstones and "red, clayey, thin-to-medium-bedded siltstones"

Size class: macrofossils

Collection methods: surface (float),

• "Virtually all specimens were found through prospecting and surface collecting"

Primary reference: W. J. Morris. 1966. Fossil mammals from Baja California: new evidence on early Tertiary migrations. Science 153:1376-1378 [J. Alroy/J. Alroy/J. Alroy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 15671: authorized by John Alroy, entered by John Alroy on 18.02.1993, edited by Jonathan Marcot

Creative Commons license: CC BY (attribution)

Taxonomic list

• treated as a unit fauna because several important specimens are from unknown localities; most localities are from a single square kilometer

•entire sequence falls within a reversely magnetized zone, presumed to be either 23R or 24n.1.r/2r; if so, no more than 0.63 m.y. are represented; however, there is nothing to rule out 24R, which spans 2.73 m.y. (see Cande & Kent 1992)"Eotitanops cf. princeps" could be from a higher level than the rest of the fauna, based on preservation and uncertain provenance; assigned to E. borealis by Gunnell and Yarborough 2000

unclassified
  -
Gastropoda
  -
Gastropoda indet.5 Cuvier 1797 snail
"planispiral"
Chondrichthyes
 Carchariniformes - Triakidae
cf. Galeorhinus sp.5 de Blainville and Prévost 1816 school shark
Osteichthyes
 Caudata -
Caudata indet.5 salamander
"genus, new?"
Reptilia
 Squamata -
cf. Saniwa sp.5 Leidy 1870 lizard
 Squamata - Iguanidae
Iguanidae indet.5 Oppel 1811 lizard
 Squamata - Boidae
Boidae indet.5 Gray 1825 boa
Mammalia
 Cimolesta - Pantolambdidae
"Barylambda jackwilsoni" = Caenolambda jepseni3
"Barylambda jackwilsoni" = Caenolambda jepseni3 Simons 1960 pantodont
said to be a new genus
 Cimolesta - Esthonychidae
cf. Esthonyx sp. Cope 1874 tillodont
sensu stricto according to Novacek et al.
 Rodentia - Paramyidae
? Paramyidae indet.5 Miller and Gidley 1918 rodent
 Condylarthra - Hyopsodontidae
cf. Hyopsodus sp.5 Leidy 1870 condylarth
 Tribosphenida - Phenacodontidae
Ectocion ignotum n. sp.4 Novacek et al. 1991 condylarth
said to be new
Meniscotherium chamense3 Cope 1874 condylarth
Phenacodus vortmani5 Cope 1880 condylarth
 Perissodactyla - Equidae
Eohippus cf. angustidens2 Cope 1875 horse
Eohippus cf. angustidens2 Cope 1875 horse
 Ferae -
Ferae indet.4 placental
 Creodonta - Oxyaenidae
cf. Oxyaena sp.5 Cope 1874 creodont
authors acknowledge this could be Dipsalidictis
 Acreodi -
Wyolestes iglesius n. sp.4 Novacek et al. 1991 mesonychian
said to be new
 Acreodi - Mesonychidae
Dissacus sp.1 Cope 1881 condylarth
 Hyaenodonta - Hyaenodontidae
Prolimnocyon sp.5 Matthew and Granger 1915 eutherian
 Didelphimorphia - Didelphidae
Esteslestes ensis n. sp.4 Novacek et al. 1991 opossum
said to be a new genus
 Artiodactyla - Diacodexeidae
Diacodexis cf. gracilis4 Krishtalka and Stucky 1985 even-toed ungulate
Dicotyledonae
 Urticales - Dilleniidae
Ulmaceae indet.5 de Mirbel 1815
seeds
Celtis sp.5 Linnaeus 1753 hackberry
seeds
Magnoliopsida
 Caryophyllales - Chenopodiaceae
Chenopodiaceae indet.5 Ventenat
seeds