El Rosario (Cretaceous of Mexico)

Also known as LACM 3302, 3310, 7172

Where: Baja California, Mexico (30.2° N, 115.8° W: paleocoordinates 35.7° N, 86.5° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: El Gallo Formation, Late/Upper Campanian (83.5 - 70.6 Ma)

• said to be Campanian

• formation-level stratigraphic resolution

Environment/lithology: terrestrial; lithology not reported

Size classes: macrofossils, mesofossils

Collected by H. Garbani, M. Greenwald in 1970, 1973; reposited in the LACM

Collection methods: bulk, quarrying, surface (float), surface (in situ), sieve,

• collections were eventually moved from the LACM to the IGM (Nydam 1999)

Primary reference: W. J. Morris. 1973. Mesozoic and Tertiary vertebrates in Baja California. National Geographic Society Research Reports (1966) 7:197-209 [M. Carrano/M. Carrano/M. Carrano]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 14456: authorized by John Alroy, entered by John Alroy on 30.04.1994, edited by Matthew Carrano and Jonathan Tennant

Creative Commons license: CC BY (attribution)

Taxonomic list

• Ferrusquia 1978 claims there is a "radiometric" date of 73 Ma, which if true places close to the Campanian - Maastrichtian boundary. Said to be Campanian based on ammonites. Date is K-Ar reported in ref 30749 as 73 ± 2 Ma.
Mammalia
 Theriamorpha - Zhelestidae
Gallolestes pachymandibularis n. gen. n. sp.3 Lillegraven 1976 eutherian
from LACM 3302; also at LACM 3310, LACM 7172: Clemens 1980
 Theriamorpha - Pediomyidae
Pediomyidae indet.1 Simpson 1927 metatherian
 Multituberculata - Neoplagiaulacidae
Mesodma cf. formosa Marsh 1889 multituberculate
 Multituberculata - Eucosmodontidae
? Stygimys sp. Sloan and Van Valen 1965 multituberculate
"n. sp."
Reptilia
 Squamata - Polyglyphanodontidae
"Polyglyphanodon bajaensis n. sp." = Dicothodon bajaensis4
"Polyglyphanodon bajaensis n. sp." = Dicothodon bajaensis4 Nydam 1999 squamates
type from LACM LAV-7170, also at LACM LAV-7272
 Testudinata - Helochelydridae
Naomichelys sp.5 Hay 1908 turtle
Amphibia
 Salientia -
Scotiophryne sp.2 Estes 1969 frog