# Sabinal Formation

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 Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Planohybodus | P. sp. | Yosobé | Kimmeridgian | Teeth | A hybodont. | |

### Ray-finned fish

Ray-finned fish of the Sabinal Formation' :
| Genus | Species | Location | Stratigraphic position | Material | Notes |
| Belonostomus | B. ornatus | Cerro de la Virgen | Berriasian | | An aspidorhynchid. |
| Gyrodus | G. sp. | Yosobé | Kimmeridgian | Teeth, partial skeleton | A pycnodont. The most abundant vertebrate fossil in the formation. |
| Nhanulepisosteus | N. mexicanus | Yosobé | Kimmeridgian | Partial cranium | A gar, the earliest known from the fossil record. |
| Otomitla | O. mexicana | Cerro de la Virgen | Berriasian | | An ichthyodectiform. |
| Otomitla | O. speciosa | Cerro de la Virgen | Berriasian | | An ichthyodectiform. |
| Pleuropholidae indet. | | Yosobé | Kimmeridgian | Trunk with scales | A pleuropholid. |
| Pleuropholis | P. cisnerosorum | Yosobé | Kimmeridgian | Partial skull | A pleuropholid. |
| ?Thrissops | T. sp. | Cerro de la Virgen | Berriasian | | An ichthyodectiform. |
| Vinctifer | V. ferrusquiai | Yosobé | Kimmeridgian | Parts of head and trunk | An aspidorhynchid. |

### Reptiles
#### Crocodylomorphs

Crocodylomorphs of the Sabinal Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Maledictosuchus | M. nuyivijanan | Yosobé | Kimmeridgian | Nearly complete cranium, jaws, and some vertebrae | A metriorhynchid thalattosuchian. First record of this genus outside Europe. | |
| Torvoneustes | T. mexicanus (=Plesiosaurus mexicanus, Cricosaurus mexicanus) | Unknown, but most likely Yosobé | Kimmeridgian | Parts of cranium and jaws | A metriorhynchid thalattosuchian. First record of this genus outside Europe. | |

#### Turtles

Turtles of the Sabinal Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Notoemys | N. tlaxiacoensis | Yosobé | Kimmeridgian | Nearly complete carapace with plastron | A stem-group sideneck turtle. | |

#### Plesiosaurs

Plesiosaurs of the Sabinal Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Liopleurodon | L. sp. | Yosobé | Kimmeridgian | Partial jaw with teeth | A pliosaur. First record of this genus outside Europe. | |
| Pliosauridae indet. | | Yosobé | Kimmeridgian | Vertebrae and ribs | An indeterminate pliosaur. Remains appear to have been scavenged by Planohybodus. | |

#### Ichthyosauria

Ichthyosaurs of the Sabinal Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Ophthalmosauridae indet. | | Yosobé | Kimmeridgian | Vertebrae | An ophthalmosaurid ichthyosaur. | |