Alisitos Fm. (UCB A-8317) (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 - 112.0 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: shallow subtidal; conglomerate

• "Poorly sorted dark volcanic breccia overlying 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 1878: authorized by John Alroy, entered by Mike Sommers on 10.06.1999, edited by Jonathan Marcot, Austin Hendy and Wolfgang Kiessling

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."
Nodosariata
 Vaginulinida - Vaginulinidae
Lenticulina cf. subalta
quest. ident. - originally entered as "Lenticulina cf. subalta"
Foraminifera
 Orbitolinacea - Orbitolinidae
Demospongiae
 Clavulina - Clionaidae
Cliona sp. demosponge
Anthozoa
 Scleractinia - Astrocoeniidae
Astrocoenia sp. Milne-Edwards and Haime 1848 stony coral
 Scleractinia - Eugyridae
Myriophyllia cf. cuyleri stony coral
originally entered as "Myriophyllia cf. cuyleri"
 Scleractinia - Montlivaltiidae
Isastrea whitneyi Wells 1932 stony coral
 Scleractinia - Montastraeidae
""Montastrea" sp." = Montastraea1
""Montastrea" sp." = Montastraea1 Blainville 1830 stony coral
Gastropoda
 Trochoidea - Colloniidae
Cirsochilus gilberti n. sp. Allison 1955 snail
 Trochoidea - Trochidae
Tectus (Tectus) tomasensis n. sp. Allison 1955 top snail
 Seguenzioidea - Chilodontaidae
Agnathodonta brooksi n. sp. Allison 1955 snail
n. sp. - originally entered as "Agnathodonta brooksi"
 Cerithioidea - Turritellidae
Omalaxis ? planorbis Blainville 1827 turret shell
originally entered as "Omalaxis ? planorbis"
 Cerithioidea - Potamididae
Pyrazus (Echinobathra) austinense Roemer 1888 horn snail
Pyrazus (Echinobathra) durhami n. sp. Allison 1955 horn snail
 Sorbeoconcha - Tylostomatidae
Tylostoma allisoni3 Squires and Saul 2004 snail
 Sorbeoconcha - Aporrhaidae
Anchura (Perissoptera) hannai Allison 1955 snail
quest. ident.
 Sorbeoconcha - Naticidae
Natica importuna Nagao 1934 moon snail
 Sorbeoconcha - Procerithiidae
Uchauxia beali Allison 1955 snail
Uchauxia kirki Allison 1955 snail
Cimolithium miyakoense Nagao 1934 snail
var. tomasensis n. var.
Cimolithium eleanorae Allison 1955 snail
 Heterostropha - Acteonellidae
Actaeonella parvus Stanton 1947 snail
originally entered as "Acteonella parvus"
 Heterostropha - Acteonidae
 Heterostropha - Nerineidae
Nerinea (Plesioptygmatis) cf. pseudoconvexa Stanton 1947 snail
(Plesioptygmatis) - originally entered as "Nerinea cf. pseudoconvexa"
 Heterostropha - Nerinellidae
Aptyxiella (Aptyxiella) cf. subula Roemer 1888 snail
(Aptyxiella) - originally entered as "Aptyxiella cf. subula"
 Neritoidea - Neritidae
Semineritina apparata Cragin 1893 snail
Corsania (Corsania) allisoni n. sp.2 Saul and Squires 1997 snail
 Neritoidea - Neridomidae
Neritoma (Neridomus) delpeyae n. sp. Allison 1955 snail
  -
"? Pyrazus harrissi n. sp." = Alamirifica harrissi
"? Pyrazus harrissi n. sp." = Alamirifica harrissi Allison 1955 snail
originally entered as "? Pyzarus harrissi"
Bivalvia
 Pectinida - Limidae
Lima (Mantellum) sp. Röding 1798 file clam
(Mantellum)
 Pectinida - Neitheoidae
Neithea aff. occidentalis scallop
originally entered as "Neithea aff. occidentalis"
 Ostreida - Gryphaeidae
Exogyra cf. quitmanensis oyster
originally entered as "Exogyra cf. quitmanensis"
 Pholadida - Corbulidae
Corbula sp. Bruguière 1789 clam
 Hippuritida - Caprinuloideidae
Caprinuloidea sp. Palmer 1928 rudist
 Cardiida - Tellinidae
"Linearia sp." = Linearis
"Linearia sp." = Linearis Conrad 1860 tellin clam
 Carditida - Crassatellidae
Ptychomya ? densicostata clam
originally entered as "Ptychomya ? densicostata"
Malacostraca
 Decapoda -
Decapoda indet. Latreille 1802 decapod
crab fragments
Echinoidea
 Echinoneoida - Conulidae
Pygopyrina sp. Pomel 1883 sea urchin