The Açu Formation is an Early Cretaceous (Albian) geologic formation of the Potiguar Basin in Ceará, northeastern Brazil. The formation comprises coarse-grained sandstones deposited in a fluvio-deltaic environment. The Açu Formation, belonging to the Apodi Group, has provided fossils of an indeterminate rebbachisaurid.
Description The Açu Formation was deposited in a passive margin setting, overlying the Alagamar Formation and is overlain by the Jandaíra Formation. In the petroleum producing Potiguar Basin, the formation is a reservoir rock.Maraschin et al., 2010, p.87
Fossil content The following fossils were reported from the formation:Açu Formation at Fossilworks.org
Dinosaurs
Sauropods Sauropods of the Açu Formation Genus Species Location Stratigraphic position Material Notes Images Rebbachisauridae indet. Indeterminate Ceará Albian Vertebrae Tiamat T. valdecii Ceará Albian to Cenomanian Caudal vertebrae A titanosaurian sauropod; closely related to Andesaurus delgadoi. Titanosauria Indet. Indeterminate Ceará Albian Osteoderm
Theropods Theropods of the Açu Formation Genus Species Location Stratigraphic position Material Notes Images Abelisauridae Indet. Indeterminate Ceará Albian to Cenomanian Teeth & Completed Femur Baryonychinae Indet. Indeterminate Ceará Albian Tooth A spinosaurid theropod Carcharodontosauridae Indet. Indeterminate Ceará Albian Vertebrae Megaraptora Indet. Indeterminate Ceará Albian Vertebrae Noasauridae Indet. Indeterminate Ceará Albian to Cenomanian Teeth Paraves Indet. Indeterminate Ceará Albian Vertebrae A maniraptoran theropod Spinosaurinae Indet. Indeterminate Ceará Albian Tooth A spinosaurid theropod
Crocodylomorphs Crocodylomorps of the Açu Formation Genus Species Location Stratigraphic position Material Notes Images Candidodontidae Indet. Indeterminat Ceará Albian to Cenomanian Itasuchidae Indet. Indeterminate Ceará Albian to Cenomanian Peirosauridae Indet. Indeterminate Ceará Albian Insolated Tooth Sphagesauria Indet. Indeterminate Ceará Albian to Cenomanian
Fish Fish of the Açu Formation Genus Species Location Stratigraphic position Material Notes Images Arganodus A. tiguidiensis Ceará Albian Teeth A arganodontid lungfish Ceratodus C. brasilensis Ceará Albian Teeth A ceratodontid lungfish Bawitius B. bartheli Ceará Albian Scales & Tooth A bichir Distobatus D. potiguarense Ceará Albian to Cenomanian A distobatid hybodont Lepisosteus L. sp. Ceará Albian to Cenomanian Scales & Tooth A gar Mawsonia M. gigas Ceará Albian to Cenomanian A mawsoniid coelacanth Pycnodontiformes Indet. Indeterminate Ceará Albian Teeth Tharrhias T. castelhanoi Ceará Albian Scales A gonorynchiform fish Tribodus T. limae Ceará Albian to Cenomanian A hybodont shark Vidalamiinae Indet. Indeterminate Ceará Albian
Crustaceans Crustaceans of the Açu Formation Genus Species Location Stratigraphic position Material Notes Images Unusuropode U. castroi Ceará Albian A isopod
Molluscs
Bivalves Bivalves of the Açu Formation Genus Species Location Stratigraphic position Material Notes Images Brachidontes B. sp. Ceará Albian A mytilid mussel Mytilus M. rosadoi Ceará Albian A mytilid mussel
Gastropods Gastropods of the Açu Formation Genus Species Location Stratigraphic position Material Notes Images Gastropoda Indet. Indeterminate Ceará Albian
Echinoderms Echinoderms of the Açu Formation Genus Species Location Stratigraphic position Material Notes Images Echinodermata Indet. Indeterminate Rio Grande do Norte Albian
Plants Plants of the Açu Formation Genus Species Location Stratigraphic position Material Notes Images Palmoxylon P. sp. Rio Grande do Norte Albian
Bibliography
References