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 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."
unclassified
  -
? Pyzarus harrissi
n. sp. - originally entered as "? Pyzarus harrissi"
Textulariina
 Orbitolinacea - Orbitolinidae
Lagenina
 Nodosariacea - Nodosariidae
Lenticulina cf. subalta
quest. ident. - originally entered as "Lenticulina cf. subalta"
Malacostraca
 Decapoda -
Decapoda indet. Latreille 1802 decapod
crab fragments
Bivalvia
 Pectinida - Pectinoidae
Neithea aff. occidentalis scallop
originally entered as "Neithea aff. occidentalis"
 Pectinida - Limidae
Lima (Mantellum) sp. Röding 1798 file clam
(Mantellum)
 Ostreida - Gryphaeidae
Exogyra cf. quitmanensis oyster
originally entered as "Exogyra cf. quitmanensis"
 Carditida - Crassatellidae
Ptychomya ? densicostata clam
originally entered as "Ptychomya ? densicostata"
 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
Gastropoda
 Cephalaspida -
 Vanikoroidea - Omalaxidae
Omalaxis ? planorbis snail
originally entered as "Omalaxis ? planorbis"
 Stromboidea - Aporrhaidae
Anchura (Perissoptera) hannai snail
(Perissoptera) n. sp., quest. ident.
Tylostoma allisoni2 Squires and Saul 2004 true conch
(Tylostoma)
Natica importuna moon snail
 Sorbeoconcha - Acanthonematidae
Pyrazus (Echinobathra) austinense snail
(Echinobathra)
Pyzarus (Echinobathra) durhami horn snail
(Echinobathra) n. sp.
"Uchauxia kirki" = Procerithium horn snail
n. sp.
"Uchauxia beali" = Procerithium horn snail
n. sp.
Cimolithium miyakoense horn snail
var. tomasensis n. var.
Cimolithium eleanorae horn snail
n. sp.
  - Cerithiidae
"Actaeonella parvus" = Acteonella
"Actaeonella parvus" = Acteonella turret shell
originally entered as "Acteonella parvus"
 Neritoidea - Neritidae
 Neritoidea - Neridomidae
"Neritoma (Neridomus) delpeyae" = Neridomus
"Neritoma (Neridomus) delpeyae" = Neridomus snail
(Neridomus) n. sp.
 Heterobranchia - Nerinellidae
Aptyxiella (Aptyxiella) cf. subula snail
(Aptyxiella) - originally entered as "Aptyxiella cf. subula"
 Heterobranchia - Nerineidae
Nerinea (Plesioptygmatis) cf. pseudoconvexa snail
(Plesioptygmatis) - originally entered as "Nerinea cf. pseudoconvexa"
Nerinea (Plesioptygmatis) bosei snail
(Plesioptygmatis) n. sp.
Nerinea (Plesioptygmatis) tomasensis snail
(Plesioptygmatis) n. sp.
 Seguenzioidea - Chilodontidae
Agathodonta brooksi snail
n. sp. - originally entered as "Agnathodonta brooksi"
 Trochoidea - Trochidae
Tectus (Tectus) tomasensis top snail
(Tectus) n. sp.
Echinoidea
 Echinoneoida - Conulidae
Pygopyrina sp. Pomel 1883 sea urchin
Anthozoa
 Scleractinia - Montastraeidae
""Montastrea" sp." = Montastraea1
""Montastrea" sp." = Montastraea1 Blainville 1830 stony coral
 Scleractinia - Astrocoeniidae
Astrocoenia sp. Milne-Edwards and Haime 1848 stony coral
 Scleractinia - Montlivaltiidae
Isastrea whitneyi Wells 1932 stony coral
 Scleractinia - Faviidae
Myriophyllia cf. cuyleri stony coral
originally entered as "Myriophyllia cf. cuyleri"
Demospongea
 Clavulina - Clionaidae
Cliona sp. demosponge