Pirabas Formation (Miocene of Brazil)

Where: Para, Brazil (0.8° S, 47.1° W: paleocoordinates 0.8° S, 43.0° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Pirabas Formation, Early/Lower Miocene (23.0 - 16.0 Ma)

• Horizontal beds of limestone near sea level. Closely associated with faunas of the Gatun, Bowden, and the Gurabo and Cercado Fm, but containing Orthaulax, which is not recorded in beds younger than the Chipola Fm of Florida, older than the above units. It is also present in the Baitoa Fm of the Dominican Republic. Maury (1924) therefore considered the fauna to be of Early Miocene age. Also shows close affinities to the Aquitanian srafe of France. Maury correlates this unit to the Chipola Fm of Florida and the Aquitanian of France. This was the lowest unit yet identified in the Neogene of Brazil. Early Miocene in Vokes (1990), and is accordingly assigned to Early Miocene here.

• bed-level stratigraphic resolution

Environment/lithology: shallow subtidal; lithified, shelly/skeletal, gray limestone and lithified, sideritic, shelly/skeletal, brown limestone

• No environmental data reported.
• Fossiliferous limestone exhibits two beds, a grayish or light buff bed, a leached limestone or coquina composed of broken shells loosely cemented together and later calcified, while the other is a deeper color due to infiltration of limonite. Collection is believed to be from the lighter limestone unit.

Size class: macrofossils

Preservation: cast, mold/impression

Collection methods: quarrying,

• COLLECTOR: Unknown. COLLECTION DATE: Unknown.

Primary reference: E. H. Vokes. 1990. Cenozoic Muricidae of the western Atlantic region, Part VIII - Murex ss, Haustellum, Chicoreus, and Hexaplex; additions and corrections. Tulane Studies in Geology and Paleontology 23(1-3):1-96 [A. Hendy/A. Hendy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 111196: authorized by Austin Hendy, entered by Austin Hendy on 21.06.2011

Creative Commons license: CC BY (attribution)

Taxonomic list

• COVERAGE: Limited to Muricidae. REPOSITORY: Probably USNM, or Tulane (PRI).
Gastropoda
 Neogastropoda - Turbinellidae
"Vasum haitense" = Vasum haitensis
"Vasum haitense" = Vasum haitensis Sowerby 1850 snail
 Neogastropoda - Muricidae
Chicoreus (Triplex) cornurectus Guppy 1876 murex snail
Chicoreus (Siratus) sextoni n. sp. murex snail
Chicoreus (Siratus) yaquensis Maury 1917 murex snail
Vokesimurex messorius Sowerby 1841 murex snail
Haustellum pennae Maury 1934 murex snail
 Architectonicoidea - Architectonicidae
Architectonica nobilis Röding 1798 sundial