Lower Member, Zorritos Formation (Miocene of Peru)

Where: Tumbes, Peru (3.7° S, 80.7° W: paleocoordinates 4.9° S, 76.4° W)

• coordinate based on nearby landmark

• local area-level geographic resolution

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

• Stated as Early Miocene by Spieker (1922) and corroborated by more recent publications (e.g. see Higley 2004). Overlies the late Oligocene-early Miocene Heath Fm and underlies the Cardalitos Fm in Higley (2004) although Spieker (1922) uses varying lithostratigraphic nomenclature suggesting a "Talara Fm" overlies the upper member of the Zorritos Fm. Its is not clear whether definitions of these members has changed since Spieker. The lower member of the Zorritos Fm is 245 ft thick and comprises sandstone with interbedded shales.

• member-level stratigraphic resolution

Environment/lithology: coastal; poorly lithified, shelly/skeletal, yellow, argillaceous, conglomeratic, calcareous sandstone and poorly lithified, gray, yellow, argillaceous, calcareous, carbonaceous sandstone

• Shallow water, sandy littoral, agitated.
• Comprises: 1) heavy bedded, light yellow sandstone with shaly intercalations, pebbly, conglomeratic, red or rusty from iron stains, locally very calcarous and fossiliferous; 2) thinner bedded light colored sandstones with abundant intercalations of gray to yellow sandy shales, some of which are calcareous and carbonaceous

Size class: macrofossils

Reposited in the YPM

• Collected by J. Singewald, and with inspection of collections by E.T. Nelson (1870) at Yale University. Possibly also involved inspection of Grzybowski's material (Geol. Inst. of Cracow). Singewald's material is presumably reposited at Johns Hopkins.

Primary reference: E. M. Spieker. 1922. The Paleontology of the Zorritos Formation of the North Peruvian Oil Fields. The Johns Hopkins University Studies in Geology 3:1-196 [A. Miller/A. Hendy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 59001: authorized by Austin Hendy, entered by Austin Hendy on 05.03.2006

Creative Commons license: CC BY (attribution)

Taxonomic list

• Probably not exhaustive though certainly representative of diversity of Mollusca for these units.
 Arcida - Arcidae
Arca (Scapharca) vanholsti, "Arca (Scapharca) zapotalensis" = Scapharca, "Arca (Scapharca) charanensis" = Scapharca, "Arca (Scapharca) singewaldi" = Scapharca, "Arca (Scapharca) hispaniolana" = Anadara (Cunearca) hispaniolana, "Arca (Scapharca) fissicosta" = Anadara (Rasia) fissicosta
"Arca (Scapharca) zapotalensis" = Scapharca clam
"Arca (Scapharca) charanensis" = Scapharca clam
"Arca (Scapharca) singewaldi" = Scapharca clam
"Arca (Scapharca) hispaniolana" = Anadara (Cunearca) hispaniolana Maury 1917 ark
"Arca (Scapharca) fissicosta" = Anadara (Rasia) fissicosta Spieker 1922 ark
 Carditida - Crassatellidae
"Crassatellites (Scambula) nelsoni" = Hybolophus nelsoni, "Crassatellites (Scambula) berryi" = Eucrassatella (Hybolophus) berryi
"Crassatellites (Scambula) nelsoni" = Hybolophus nelsoni Grzybowski 1899 clam
"Crassatellites (Scambula) berryi" = Eucrassatella (Hybolophus) berryi Spieker 1922 clam
 Pholadida - Corbulidae
"Corbula (Cuneocorbula) bravoana" = Tenuicorbula bravoana, "Corbula (Aloidis) prenuncia" = Corbula, "Corbula (Cuneocorbula) fabiformis" = Cuneocorbula
"Corbula (Cuneocorbula) bravoana" = Tenuicorbula bravoana Spieker 1922 clam
"Corbula (Aloidis) prenuncia" = Corbula clam
"Corbula (Cuneocorbula) fabiformis" = Cuneocorbula clam
 Cardiida - Anatinellidae
"Labiosa (Raeta) gabbi" = Raeta gabbi, "Labiosa (Raeta) gardnerae" = Raeta gardnerae
"Labiosa (Raeta) gabbi" = Raeta gabbi Pilsbry and Johnson 1917 clam
"Labiosa (Raeta) gardnerae" = Raeta gardnerae Spieker 1922 clam
 Cardiida - Veneridae
"Chione (Chione) propinqua" = Chione (Chionopsis) propinqua, Chione (Lirophora) hendersonii, "Chione (Lirophora) latilirata" = Lirophora (Lirophora) latilirata, "Dosinia (Dosinidia) delicatissima" = Dosinia (Dosinia) delicatissima, "Pitaria (Lamelliconcha) planivieta" = Lamelliconcha, Transennella herviderana, "Clementia dariena" = Clementia (Clementia) dariena
"Chione (Chione) propinqua" = Chione (Chionopsis) propinqua Spieker 1922 venus clam
Chione (Lirophora) hendersonii Dall 1903 venus clam
"Chione (Lirophora) latilirata" = Lirophora (Lirophora) latilirata Conrad 1841 venus clam
"Dosinia (Dosinidia) delicatissima" = Dosinia (Dosinia) delicatissima Brown and Pilsbry 1913 venus clam
"Pitaria (Lamelliconcha) planivieta" = Lamelliconcha venus clam
"Clementia dariena" = Clementia (Clementia) dariena Conrad 1855 venus clam
 Cardiida - Solecurtidae
 Cardiida - Tellinidae
"Tellina (Angulus) singewaldi" = Angulus, "Tellina zapotalensis" = Psammacoma zapotalensis, "Tellina (Eurytellina) aequicincta" = Eurytellina aequicincta
"Tellina (Angulus) singewaldi" = Angulus tellin clam
"Tellina zapotalensis" = Psammacoma zapotalensis Spieker 1922 tellin clam
"Tellina (Eurytellina) aequicincta" = Eurytellina aequicincta Spieker 1922 tellin clam
 Cardiida - Cardiidae
"Cardium (Trachycardium) zorritoensis" = Trachycardium, "Cardium (Trigoniocardium) affinis" = Trigoniocardia
"Cardium (Trachycardium) zorritoensis" = Trachycardium cockle
"Cardium (Trigoniocardium) affinis" = Trigoniocardia cockle
 Lucinida - Lucinidae
"Phacoides (Pseudomiltha) insleyi" = Pseudomiltha
"Phacoides (Pseudomiltha) insleyi" = Pseudomiltha clam
 Neogastropoda - Buccinidae
Phos latirugatus Spieker 1922 true whelk
 Neogastropoda - Melongenidae
Pyrula peruviana Spieker 1922 snail
 Neogastropoda - Conidae
"Conus multiliratus" = Conasprelloides multiliratus Olsson 1922 cone shell
Subspecies: Conus multiliratus gaza
Conus berryi Spieker 1922 cone shell
Conus bocapanensis Spieker 1922 cone shell
 Neogastropoda - Terebridae
"Terebra gausapata" = Strioterebrum gausapatum
"Terebra gausapata" = Strioterebrum gausapatum Brown and Pilsbry 1911 auger snail
Subspecies: Terebra gausapata herviderana
 Naticoidea - Naticidae
Sinum carolanum Spieker 1922 moon snail
Polinices porcana Spieker 1922 moon snail
 Cypraeoidea - Cypraeidae
"Cypraea angustirima" = Muracypraea angustirima
"Cypraea angustirima" = Muracypraea angustirima Spieker 1922 cowry
 Sorbeoconcha - Potamididae
"Potamides ormei" = Potamides suprasulcatus
"Potamides ormei" = Potamides suprasulcatus Gabb 1873 horn snail
Subspecies: Potamides ormei infraliratus
 Sorbeoconcha - Turritellidae
Turritella prenuncia Spieker 1922 turret shell
"Turritella altilira" = Turritella (Bactrospira) altilira Conrad 1857 turret shell
"Turritella charana" = Turritella abrupta Spieker 1922 turret shell
Turritella filicincta Spieker 1922 turret shell
 Turbinoidea - Turbinidae
Turbo belli snail
Subspecies: Turbo belli aequifilicatus