The Feliz Deserto Formation is a geologic formation of the

Early Cretaceous The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Pro ...

age (

Berriasian In the geological timescale, the Berriasian is an age/stage of the Early/Lower Cretaceous. It is the oldest subdivision in the entire Cretaceous. It has been taken to span the time between 145.0 ± 4.0 Ma and 139.8 ± 3.0 Ma (million years ago) ...

to Valanginian) in northeastern Brazil's

Sergipe-Alagoas Basin The Sergipe-Alagoas Basin is a continental margin basin in the Sergipe and Alagoas states of northeastern Brazil, about 20 to 50 kilometres wide onshore, but with its widest extension offshore, more precisely 13,000 km2 onshore and 40,000&nbs ...

. The formation belongs to the rift phase, in which a great lake formed.

Background

The formation provided fossils of

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, bival ...

and

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

molluscs, vertebrate remains of Lepidotes fish and teeth of

crocodylomorphs Crocodylomorpha is a group of pseudosuchian archosaurs that includes the crocodilians and their extinct relatives. They were the only members of Pseudosuchia to survive the end-Triassic extinction. During Mesozoic and early Cenozoic times, cr ...

and

spinosaurids The Spinosauridae (or spinosaurids) are a clade or Family (taxonomy), family of tetanuran theropod dinosaurs comprising ten to seventeen known genera. They came into prominence during the Cretaceous Geological period, period. Spinosaurid fossils h ...

, the oldest of the family reported in South America.

References

Geologic formations Geologic formations of Brazil {{Geologic-formation-stub