Zorritos Formation (undifferentiated) (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. This list is comprised of assemblages from undifferentiated sections of the Zorritos Fm

• formation-level stratigraphic resolution

Environment/lithology: coastal; poorly lithified sandstone and poorly lithified conglomerate

• Shallow water, sandy littoral, agitated.
• Probably from sandstone and conglomeratic lithologies.

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 59002: 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. List is presumably a composite of assemblages that may belong to several members of the Zorritos Formation.
Gastropoda
 Cerithioidea - Turritellidae
Turritella alturana turret shell
Turritella prenuncia Spieker 1922 turret shell
Subspecies: Turritella prenuncia inconspicua
Turritella robusta Grzybowski 1899 turret shell
Subspecies: Turritella robusta abrupta
Turritella inca Grzybowski 1899 turret shell
 Sorbeoconcha - Tonnidae
Malea ringens Swainson 1822 tun shell
 Neogastropoda - Marginellidae
 Neogastropoda - Terebridae
Terebra tuberosa auger snail
 Neogastropoda - Nassariidae
"Murex laqueoratus" = Trajana (Trajana) laqueorata
"Murex laqueoratus" = Trajana (Trajana) laqueorata Spieker 1922 snail
 Neogastropoda - Cancellariidae
"Cancellaria (Aphera) peruana" = Aphera peruana
"Cancellaria (Aphera) peruana" = Aphera peruana Nelson 1870 snail
 Trochoidea - Trochidae
"Calliostoma (Eutrochus) noduliferum" = Calliostoma noduliferum
"Calliostoma (Eutrochus) noduliferum" = Calliostoma noduliferum Nelson 1870 top snail
 Trochoidea - Turbinidae
Bivalvia
 Nuculanida - Nuculanidae
"Leda peruviana" = Saccella peruviana
"Leda peruviana" = Saccella peruviana Dall 1895 pointed nut clam
 Cardiida - Anatinellidae
"Labiosa (Raeta) ventricosa" = Raeta
"Labiosa (Raeta) ventricosa" = Raeta clam
 Cardiida - Mactridae
 Cardiida - Veneridae
Amiantis incrassata Sowerby 1817 venus clam
Subspecies: Amiantis incrassata ovoidalis
 Cardiida - Tellinidae
"Tellina (Angulus) pressa" = Tellina (Eurytellina) pressa
"Tellina (Angulus) pressa" = Tellina (Eurytellina) pressa Dall 1900 tellin clam
 Cardiida - Solecurtidae
"Tagelus gibbus" = Tagelus plebeius
"Tagelus gibbus" = Tagelus plebeius Lightfoot 1786 clam
 Cardiida - Cardiidae
"Cardium (Trachycardium) peruvianum" = Trachycardium
"Cardium (Trachycardium) peruvianum" = Trachycardium cockle
 Pholadida - Corbulidae
"Corbula (Aloidis) bradleyi" = Varicorbula bradleyi
"Corbula (Aloidis) bradleyi" = Varicorbula bradleyi Nelson 1870 clam
 Arcida - Arcidae
"Arca (Scapharca) larkinii" = Larkinia larkinii, "Arca (Cunearca) zorritoensis" = Anadara (Cunearca) zorritoensis
"Arca (Scapharca) larkinii" = Larkinia larkinii Nelson 1870 ark
"Arca (Cunearca) zorritoensis" = Anadara (Cunearca) zorritoensis Spieker 1922 ark