# Cerro del Pueblo Formation

The Cerro del Pueblo Formation is a geological formation in Coahuila, Mexico, whose strata date back to the latest Campanian of the Late Cretaceous, just before the Campanian-Maastrichtian boundary. Dinosaur remains are among the fossils that have been recovered from the formation. The formation is believed to correlate with the Baculites reesidesi and Baculites jenseni ammonite zones, which dates it to 73.63-72.74 Ma.
The Cerro del Pueblo Formation includes marine, brackish, and non-marine environments, and was laid down in a coastal lowland environment, with Coahuila being on the edge of the Western Interior Seaway at the time. Fossils are abundant in the Cerro del Pueblo Formation, and include dinosaurs and other vertebrates, plants and seeds, and invertebrates including oysters, snails, and other molluscs. The formation is underlain by the Parras Shale and is overlain by the Cerro Huerta Formation.

## Dinosaurs
### Ornithischians

Remains of the following ornithischians have been found in the formation:

#### Ankylosaurs

Ankylosaurs of the Cerro del Pueblo Formation :
| Genus | Species | Material | Notes |
| Ankylosauria | Indeterminate | A femur fragment, phalanx and a possible osteoderm. | Indeterminate ankylosaur remains. |
| Ankylosauridae | Indeterminate | Osteoderms. | Indeterminate ankylosaurid remains. |
| Nodosauridae | Indeterminate | A caudal vertebra, osteoderms and a tooth. | Indeterminate nodosaurid remains. |

#### Ceratopsians

Ceratopsians of the Cerro del Pueblo Formation :
| Genus | Species | Material | Notes |
| Centrosaurinae | Indeterminate | A partial right squamosal. | Probably represents a new taxon. |
| Ceratopsidae | Indeterminate | Squamosal fragment, metatarsal, metacarpal, sacral vertebrae, proximal end of femora, proximal end of ulna, possible frill fragments and teeth. | Indeterminate ceratopsid remains. |
| Chasmosaurinae | Indeterminate | Supraorbital horncores, an orbit, dorsal vertebra, indeterminate cranial fragments, limb bones, and unspecified postcranial elements pertaining to juvenile specimens. | Indeterminate chasmosaurine remains belonging to juvenile specimens. |

#### Ornithopods

Ornithopods of the Cerro del Pueblo Formation :
| Genus | Species | Material | Notes | Images |
| Coahuilasaurus | C. lipani | | A kritosaurin hadrosaurid | CoahuilasaurusLatirhinus Tlatolophus Velafrons |
| Hadrosauridae | Indeterminate | A braincase, postorbital, quadrate, laterosphenoid, dentaries, mandibles, maxillae, cervical vertebrae, dorsal vertebrae, sacral vertebrae, caudal vertebrae, neural spines, ribs, ilium, femora, fibulae, tibiae, humeri, ulnae, metatarsals, metacarpals, pedal phalanxes, pedal phalanges, pedal ungula, phalanges, phalanxes, various bone fragments, fibulae, scapulae, radii, coracoids, astragali, indeterminate pelvic bones, ossified tendons, isolated teeth and integumentary impressions. | Indeterminate hadrosaurid remains from numerous specimens. | CoahuilasaurusLatirhinus Tlatolophus Velafrons |
| Kritosaurus | K. navajovius | Predentary, symphyseal processes, rostral portion of dental battery of dentaries, rostral region of premaxillae, and fragments of maxilla. | A kritosaurin hadrosaurid, originally referred to K. navajovius, but reclassified to Coahuilasaurus. | CoahuilasaurusLatirhinus Tlatolophus Velafrons |
| Lambeosaurinae | Indeterminate | Maxillae, premaxillae, quadrate, partial braincase, dentaries, cervical vertebrae, dorsal vertebrae, sacral vertebrae, caudal vertebrae, neural spines, ribs, ilia, ischium, femora, fibulae, tibiae, humeri, ulnae, metatarsals, metacarpals, pedal phalanges, phalanges, pedal unguals, astragali, radii, scapulae, pubes and other unprepared elements. | Indeterminate lambeosaurine remains from numerous specimens, including a large hadrosaurid. | CoahuilasaurusLatirhinus Tlatolophus Velafrons |
| Latirhinus | L. uitstlani | Caudal vertebrae, scapulae, humeri, ulnae, coracoid, metacarpals, manual ungual, ilia, ischia, femora, tibiae, fibula, and astragalus. | Holotype specimen is chimeric as it consists of multiple individuals. Some material from the holotype specimen is assigned to Lambeosaurinae indet. and Saurolophinae indet.. | CoahuilasaurusLatirhinus Tlatolophus Velafrons |
| Saurolophinae | Indeterminate | A braincase, brain endocast, dentaries, maxillae, cervical vertebrae, dorsal vertebrae, sacral vertebrae, caudal vertebrae, chevrons, neural spines, ribs, ilium fragments, femora, fibulae, tibiae, humeri, ulnae, metatarsals, phalanges, phalanxes, scapulae, a possible coracoid, radii, ossified tendons, and undescribed juvenile specimens. | Indeterminate saurolophine remains from numerous specimens, including juvenile individuals. | CoahuilasaurusLatirhinus Tlatolophus Velafrons |
| Tlatolophus | T. galorum | An almost complete skull, mandible, partial ilium, partial ischium, a femur, scapula, coracoid, sacral vertebrae, caudal vertebrae, and chevrons. | A parasaurolophin hadrosaur, closely related to Charonosaurus and Blasisaurus. | CoahuilasaurusLatirhinus Tlatolophus Velafrons |
| Velafrons | V. coahuilensis | Dentaries, predentaries, ceratobranchial, premaxillae, maxillae, jugal, quadrate, nasal, skull roof, cervical vertebrae, dorsal vertebrae, sacral vertebrae, caudal vertebrae, neural arches, cervical ribs, ribs, chevrons, scapula, coracoids, humeri, ulnae, radii, metacarpals, manual phalanges, ilium, ischia, pubes, femora, tibiae, astragalus, metatarsals and pedal phalanges. | A lambeosaurine hadrosaurid known only from a juvenile specimen. | CoahuilasaurusLatirhinus Tlatolophus Velafrons |

#### Thescelosaurids

Thescelosaurids of the Cerro del Pueblo Formation :
| Genus | Species | Material | Notes | Images |
| Thescelosauridae | Indeterminate | A right premaxillary tooth and a posterior sacral vertebral centrum. | Indeterminate thescelosaurid remains. |

### Saurischians

Remains of the following saurischians have been found in the formation:

#### Theropods
##### Coelurosaurs

Coelurosaurs of the Cerro del Pueblo Formation :
| Genus | Species | Material | Notes | Images |
| cf. Richardoestesia | Indeterminate | A tooth. | A taxon only known from teeth. | |

##### Dromaeosaurs

Dromaeosaurs of the Cerro del Pueblo Formation :
| Genus | Species | Material | Notes | Images |
| Dromaeosaurinae | Indeterminate | A pedal ungual and dentary teeth. | Indeterminate dromaeosaurine remains. | |
| Saurornitholestinae | Indeterminate | A pedal ungual, manual unguals and teeth. | Indeterminate saurornitholestine remains. | |

##### Oviraptorosaurs

Oviraptorosaurs of the Cerro del Pueblo Formation :
| Genus | Species | Material | Notes | Images |
| Caenagnathidae | | 3 tibia fragments, distal, proximal and medial shaft elements respectively. | An oviraptorosaur. Two different morphotypes are suggested, a small one, less than a meter in length. And a big morphotype, almost reaching two meters. | |

##### Ornithomimosaurs

Ornithomimosaurs of the Cerro del Pueblo Formation :
| Genus | Species | Material | Notes |
| Mexidracon | M. longimanus | A partial skeleton | A ornithomimid theropod |
| Paraxenisaurus | P. normalensis | Caudal vertebrae, femur, peses, manual phalanxes, manual ungual, tarsals, metatarsals, metacarpals, pedal phalanx, pedal phalanges, and pedal unguals. | Represents the first known deinocheirid from North America. |
| "Saltillomimus" | "S. rapidus" | Partial skeleton. | An informally named ornithomimosaur. |

##### Tyrannosaurs

Tyrannosaurs of the Cerro del Pueblo Formation :
| Genus | Species | Material | Notes | Images |
| Labocania | L. aguillonae | | A teratophonein tyrannosaurine | |
| Tyrannosauridae | Indeterminate | A caudal vertebra, indeterminate vertebrae, tibia, fibula, fragments of ungual phalanges, phalanges, and teeth. | Indeterminate tyrannosaurid remains. | |

##### Other theropods

Theropods of the Cerro del Pueblo Formation :
| Genus | Species | Material | Notes | Images |
| Theropoda | Indeterminate | A neural arch, complete and fragmented pedal and manual phalanxes, manual unguals, unspecified vertebra, complete and fragmented caudal vertebrae, chevron, proximal end of femur, and unidentified bone fragments. | Indeterminate theropod remains. | |
| Troodontidae | Indeterminate | A pedal phalanx and a tooth. | Indeterminate troodontid remains. | |

## Other Fossils
### Pterosaurs

Pterosaurs of the Cerro del Pueblo Formation :
| Taxa | Presence | Description | Images |
| Ichnogenus: Pteraichnus | Saltillo, Coahuila | Specimens kept at the Dinosaur Tracks Museum, of the University of Colorado at Denver and the Secretaría de Educación Pública de Coahuila, Mexico; might also represent Haenamichnus. | |

### Turtles

Turtles of the Cerro del Pueblo Formation :
| Genus | Species | Notes |
| Mexichelys | M. coahuilaensis | New genus for Euclastes coahuilaensis, sea turtle |
| Chedighaii | C. hutchisoni | A bothremydid turtle |
| Yelmochelys | Y. rosarioae | A stem-kinosternid turtle |
| Color key Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon | Notes Uncertain or tentative taxa are in small text; crossed out taxa are discredited. |

### Other vertebrates
#### Fish

Fish of the Cerro del Pueblo Formation :
| Genus | Species | Material | Notes | Images |
| Lepisosteus | L. sp. | | | |
| Amiidae | Indet. | | | |

#### Fossil eggs

* Porituberoolithus sp.
* Spheroolithus sp.
* ?Prismatoolithus sp.

#### Mammals

Mammals of the Cerro del Pueblo Formation :
| Genus | Species | Notes |
| Cimolomyidae indet. | | A cimolomyid multituberculate. |
| Pediomys | P. cf. elegans | A pediomyid tribosphenidan. |
| Taeniolabidoidae indet. | | A taeniolabidoid multituberculate. |
| Turgidodon | T. cf. russelli | An alphadontid marsupialiform. |