Alisitos Fm. (UCB A-8313) (Cretaceous of Mexico)

Where: Baja California, Mexico (31.5° N, 116.7° W: paleocoordinates 29.9° N, 68.2° W)

• small collection-level geographic resolution

When: upper Member (Alisitos Formation), Late/Upper Aptian (122.5 - 113.0 Ma)

• Age: "Aptian to middle Albian." Squires and Saul (2004) confirming and following Allison (1974) place this collection in the Late Aptian.

• bed-level stratigraphic resolution

Environment/lithology: reef, buildup or bioherm; carbonate

• "Biostrome composed almost entirely of Nerinea, cropping out in a small cove on the north side of main Punta China promontory ~7 m strat above A-8318."

Collection methods: mechanical,

Primary reference: E. C. Allison. 1955. Middle Cretaceous gastropoda from Punta China, Baja California, Mexico. Journal of Paleontology 29(3):400-432 [J. Alroy/M. Sommers/J. Alroy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 1874: authorized by John Alroy, entered by Mike Sommers on 10.06.1999

Creative Commons license: CC BY (attribution)

Taxonomic list

• Abundances: A = 20+, C = 6-20, F = 3-5, R = 1-2. "A spectacular feature of the middle Albian deposits at Punta China is the fine preservation exhibited by many of the fossils. Despite the coarseness of some of the volcanic breccias, fragile tests of Forams, echinoids, and small molluscs are almost perfectly preserved. Pelecypods almost always occur with both valves intact. Some gastropods retain original pigmentation."
Show authors, comments, and common names
Gastropoda
 Heterostropha - Nerineidae
Nerinea (Plesioptygmatis) tomasensis n. sp., Nerinea (Plesioptygmatis) bosei
Nerinea (Plesioptygmatis) tomasensis n. sp. Allison 1955 snail
(Plesioptygmatis) n. sp.
Nerinea (Plesioptygmatis) bosei Allison 1955 snail
(Plesioptygmatis) n. sp.