The Onzole Formation is an

Early Pliocene Early may refer to: History * The beginning or oldest part of a defined historical period, as opposed to middle or late periods, e.g.: ** Early Christianity ** Early modern Europe Places in the United States * Early, Iowa * Early, Texas * Early ...

(

Montehermosan The Montehermosan age is a period of geologic time (6.8–4.0 Ma) within the Miocene and Pliocene epochs of the Neogene used more specifically with South American Land Mammal Ages. It follows the Huayquerian and precedes the Chapadmalalan The C ...

to Chapadmalalan in the SALMA classification) geologic

formation Formation may refer to: Linguistics * Back-formation, the process of creating a new lexeme by removing or affixes * Word formation, the creation of a new word by adding affixes Mathematics and science * Cave formation or speleothem, a secondar ...

in the Borbón Basin of northwestern

Ecuador Ecuador ( ; ; Quechua: ''Ikwayur''; Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechua: ''Ikwadur Ripuwlika''; Shuar: ' ...

. The formation consists of a shallow marine

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

member containing many fish fossils, among which

megalodon Megalodon (''Otodus megalodon''), meaning "big tooth", is an extinct species of mackerel shark that lived approximately 23 to 3.6 million years ago (Mya), from the Early Miocene to the Pliocene epochs. It was formerly thought to be a membe ...

, and a deep water member comprising

tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock ...

aceous shales and mudstones containing gastropods, bivalves and scaphopods.

Subdivision

The formation consists of the Esmeraldas Member, which is a unit comprising highly

foraminifera Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly ...

tuffaceous Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock c ...

calcareous Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines. In zoology ''Calcareous'' is used as an ad ...

shale. They were deposited by shallow water

gravity flow In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the stron ...

s, which brought the Esmeraldas fauna into the deep water () from shallow water, on the order of .Esmeraldas Beds
at Fossilworks.org The Esmeraldas Member is covered by the Súa Member comprising burrowed, bioturbated,

silt Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension with water. Silt usually has a floury feel ...

s deposited in a coastal environment.

Fossil content

The formation has provided bivalve, gastropod, and scaphopod fossils and the following vertebrates:Punta la Colorada
at Fossilworks.org * ''

Carcharhinus egertoni ''Carcharhinus'' is the type genus of the family Carcharhinidae, the requiem sharks. One of 12 genera in its family, it contains over half of the species therein. It contains 35 extant and eight extinct species to date, with likely more species y ...

'', '' C. priscus'' * ''

Carcharocles megalodon Megalodon (''Otodus megalodon''), meaning "big tooth", is an extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the deat ...

'' * '' Diaphus ecuadorensis''Schwarzhans & Aguilera, 2013 * ''

Galeocerdo aduncus ''Galeocerdo'' is a genus of requiem sharks that have lived since the Paleocene epoch. While these sharks were formerly diverse, only ''G. cuvier'' (the modern tiger shark) survives today. Species Species in the genus ''Galeocerdo'' include: ...

'' * ''

Hemipristis serra ''Hemipristis serra'' is an extinct species of weasel shark which existed during the Miocene epoch. It was described by Louis Agassiz Jean Louis Rodolphe Agassiz ( ; ) FRS (For) FRSE (May 28, 1807 – December 14, 1873) was a Swiss-born ...

'' * '' Isistius triangulus'' * '' Negaprion eurybathrodon'' * '' Odontaspis acutissima'' * '' Rhizoprionodon taxandriae'' * '' Brotula cf. ordwayi'' * '' Chilara taylori'' * '' Eucinostomus cf. currani'' * '' Larimus cf. pacificus'' * '' Lepophidium borbonensis'', '' L. limulum''Schwarzhans & Aguilera, 2016 * '' Lepophidium microlepis'' * '' Merluccius cf. angustimanus'' * '' Orthopristis cf. cantharinus'' * ''

Otophidium indefatigabile ''Otophidium'' is a genus of cusk-eels, part of the subfamily Ophidiinae in the family Ophidiidae. They are found in the western Atlantic and eastern Pacific. Species There are currently four recognized species in this genus: * ''Otophidium chi ...

'' * ''

Paraconger californiensis The Californian conger (''Paraconger californiensis''), also known as the ringeye conger,

'' * '' Porichthys analis'', ''

Porichthys margaritatus A midshipman fish is any species of toadfish belonging to the genus ''Porichthys'' (in family Batrachoididae). Midshipman fish are distinguished by their photophores (organs which attract prey and after which they are named, being said to resembl ...

'', '' Porichthys cf. notatus'' * '' Stellifer onzole''Aguilera et al., 2016 * '' Anchoa sp.'' * '' Apogon sp.'' * '' Citharichthys sp.'' * '' Diaphus sp.'' * '' Haemulon sp.'' * '' Lampadena sp.'' * Apogonidae indet. * Cynoglossidae indet. * Gobiidae indet. * Gerreidae indet. * Opistognathidae indet. * Pleuronectidae indet. * ?Serranidae indet.

References

Bibliography

* * * {{cite LSA , last=Schwarzhans , first=Werner , last2=Aguilera , first2=Órangel , year=2013 , title=Otoliths of the Myctophidae from the Neogene of tropical America , url=http://www.pfeil-verlag.de/07pala/e4_66.php , journal= Palaeo Ichthyologica , volume=13 , pages=83–150 , accessdate=2019-02-09

Subdivision

Fossil content

See also

References

Bibliography

Further reading