The Agua Nueva Formation is a geologic formation in Mexico. It preserves fossils dated to the latest Cenomanian and Turonian ages of the Cretaceous period. It consists "predominantly of alternating fossiliferous, organic matter-rich, laminated, dark gray limestone and non-laminated, organic matter-poor limestone in decimeter-thick beds (10 to 30 cm) with occasional centimetric beds (5 cm) of brown shale that show no apparent internal structures." The formation is noted for its qualities as a Konservat-Lagerstätte, with notable finds including the plesiosaur Mauriciosaurus, the mosasaur Yaguarasaurus and sharks Ptychodus and Aquilolamna.
It appears to have been deposited on the upper part of a shallow continental shelf.
Fossil content
Cartilaginous fish Cartilaginous fish of the Agua Nueva FormationGenusSpeciesLocationMemberMaterialNotesImagesAquilolamnaA. milarcaeComplete skeletonA bizarre aquilolamnid shark.Lamniformes indet.Articulated vertebraeAn indeterminate mackerel shark, potentially a cretoxyrhinid.PtychodusP. decurrensVallecilloTeethA ptychodontid shark.P. mortoniTeethP. sp.Complete skeletonscf. ScyliorhinusS. sp.Articulated vertebraeA catshark.
Ray-finned fish Based on Amalfitano et al (2020): Ray-finned fish of the Agua Nueva FormationGenusSpeciesLocationMemberMaterialNotesImagesAraripichthysA. sp.An araripichthyid.BelonostomusB. sp.An aspidorhynchid.Clupeoidei indet.HuehuetlaA relative of herrings.EnchodusE. sp.HuehuetlaAn enchodontid aulopiform.GoulmimichthysG. robertiVallecillo, HuehuetlaA pachyrhizodontid crossognathiform.HastichthysH. sp.HuehuetlaA dercetid aulopiform."Nursallia""N." tethysensisHuehuetlaA pycnodont.PachyrhizodusP. caninusA pachyrhizodontid crossognathiform.ParanursalliaP. gutturosaA pycnodont.RhynchodercetisR. regioA dercetid aulopiform.TingitanichthysT. sp.A pachyrhizodontid crossognathiform.TselfatiaT. formosaHuehuetlaA plethodid tselfatiiform.VallecillichthysV. multivertebratumVallecilloA saurodontid ichthyodectiform.
Lobe-finned fish Lobe-finned fish of the Agua Nueva FormationGenusSpeciesLocationMemberMaterialNotesImagesLatimerioidei indet.Gular plateA large-sized marine coelacanth, potentially Megalocoelacanthus. Originally interpreted as a cephalopod gladius and given the name "Palaeoctopus pelagicus".
Reptiles
Mosasaurs Mosasaurs of the Agua Nueva FormationGenusSpeciesLocationMemberMaterialNotesImagesYaguarasaurusY. regiomontanusA plioplatecarpine mosasaur.
Plesiosaurs Plesiosaurs of the Agua Nueva FormationGenusSpeciesLocationMemberMaterialNotesImagesMauriciosaurusM. fernandeziA polycotylid plesiosaur.
Molluscs
Cephalopods Cephalopods of the Agua Nueva Formation Genus Species Location Stratigraphic position Material Notes Images
See also
List of fossiliferous stratigraphic units in Mexico
References
External links