The Sabinal Formation is a Late Jurassic and Early Cretaceous-aged geological formation in Oaxaca, Mexico. It preserves a highly diverse marine fauna.
It was initially thought to only encompass the Late Jurassic (Kimmeridgian & Tithonian), but more recent studies have redefined it to cover the earliest Cretaceous (Berriasian & Valanginian) as well. It is part of the Tlaxiaco Basin, a prominent structural basin in southern Mexico that accumulated both continental and marine sediments between the Early Jurassic and the Paleogene. The most prolific site of the formation is the Kimmeridgian-aged Llano Yosobe site near Tlaxiaco.
Vertebrate paleobiota
Cartilaginous fish Cartilaginous fish of the Sabinal FormationGenusSpeciesLocationStratigraphic positionMaterialNotesImagesPlanohybodusP. sp.YosobéKimmeridgianTeethA hybodont.
Ray-finned fish Ray-finned fish of the Sabinal Formation'GenusSpeciesLocationStratigraphic positionMaterialNotesImagesBelonostomusB. ornatusCerro de la VirgenBerriasianAn aspidorhynchid.GyrodusG. sp.YosobéKimmeridgianTeeth, partial skeletonA pycnodont. The most abundant vertebrate fossil in the formation.NhanulepisosteusN. mexicanusYosobéKimmeridgianPartial craniumA gar, the earliest known from the fossil record.OtomitlaO. mexicanaCerro de la VirgenBerriasianAn ichthyodectiform.O. speciosaPleuropholidae indet.YosobéKimmeridgianTrunk with scalesA pleuropholid.PleuropholisP. cisnerosorumYosobéKimmeridgianPartial skullA pleuropholid.?ThrissopsT. sp.Cerro de la VirgenBerriasianAn ichthyodectiform.VinctiferV. ferrusquiaiYosobéKimmeridgianParts of head and trunkAn aspidorhynchid.
Reptiles
Crocodylomorphs Crocodylomorphs of the Sabinal FormationGenusSpeciesLocationStratigraphic positionMaterialNotesImagesMaledictosuchusM. nuyivijananYosobéKimmeridgianNearly complete cranium, jaws, and some vertebraeA metriorhynchid thalattosuchian. First record of this genus outside Europe.TorvoneustesT. mexicanus (=Plesiosaurus mexicanus, Cricosaurus mexicanus)Unknown, but most likely YosobéKimmeridgianParts of cranium and jawsA metriorhynchid thalattosuchian. First record of this genus outside Europe.
Turtles Turtles of the Sabinal FormationGenusSpeciesLocationStratigraphic positionMaterialNotesImagesNotoemysN. tlaxiacoensisYosobéKimmeridgianNearly complete carapace with plastronA stem-group sideneck turtle.
Plesiosaurs Plesiosaurs of the Sabinal FormationGenusSpeciesLocationStratigraphic positionMaterialNotesImagesLiopleurodonL. sp.YosobéKimmeridgianPartial jaw with teethA pliosaur. First record of this genus outside Europe.Pliosauridae indet.YosobéKimmeridgianVertebrae and ribsAn indeterminate pliosaur. Remains appear to have been scavenged by Planohybodus.
Ichthyosauria Ichthyosaurs of the Sabinal FormationGenusSpeciesLocationStratigraphic positionMaterialNotesImagesOphthalmosauridae indet.YosobéKimmeridgianVertebraeAn ophthalmosaurid ichthyosaur.
References