|Sub-units||Lower, Middle and Upper Members|
|Underlies||Unconformity with Eocene-Oligocene Pie de Vaca Formation|
|Thickness||Lower: 50 m Middle: 35 m Upper: 40 m|
|Named for||Tlayúa Quarry|
The Tlayúa Formation is an Early Cretaceous (late Albian) geological formation near Tepexi de Rodríguez, Puebla.
The formation contains a diverse array of vertebrate and invertebrate fossils. About 70% of the macrofossils are osteichthyan fish.Other vertebrates include chelonians, pterosaurs, lepidosaurs, and crocodiles. Cyanobacteria, foraminifera, algae, gymnosperms, sponges, cnidarians, annelids, gastropods, ammonites, bivalves, arachnids, insects, isopods, anomurans, brachyurans, crinoids, echinoids, holothuroids, stelleroids, and ophiuroids, have also been recovered from the Tlayúa Formation.
|Huehuecuetzpalli||H. mixtecus||A primitive lizard|
|Pamizinsaurus||P. tlayuaensis||An osteoderm-covered sphenodontian|
|Ankylosphenodon||A. pachyostosus||An aquatic sphenodontian|
|Tepexisaurus||T. tepexii||A basal scincomorph|
Axelrodichthys is an extinct genus of mawsoniid coelacanth from the Cretaceous of Africa, North and South America, and Europe. Several species are known, the remains of which were discovered in the Lower Cretaceous (Aptian-Albian) of Brazil, North Africa, and possibly Mexico, as well as in the Upper Cretaceous of Morocco (Cenomanian), Madagascar and France. The Axelrodichthys of the Lower Cretaceous frequented both brackish and coastal marine waters while the most recent species lived exclusively in fresh waters. The French specimens are the last known fresh water coelacanths. Most of the species of this genus reached 1 metre to 2 metres in length. Axelrodichthys was named in 1986 by John G. Maisey in honor of the American ichthyologist Herbert R. Axelrod.
Mortoniceras is an ammonoid genus belonging to the superfamily Acanthocerataceae, named by Meek in 1876, based on Ammonites vespertinu, named by Morton in 1834.
The La Boca Formation is a geological formation in Tamaulipas state, northeast Mexico. It was thought to date back to the Early Jurassic, concretely the Pliensbachian stage epoch. Although, the latest studies had proven that the local Vulcanism, related to the aperture of the Atlantic Ocean and the several Rift Events, that continue until the Bajocian, while the unit itself was likely deposited between the earliest Pliensbachian, as proven by zircon with the fossil taxa deposited on the rocks above, likely of Late Pliensbachian-Lower Toarcian age, and the upper section of Late Toarcian-Late Aalenian age. Due to successions of Aalenian depositional sistems on the upper layers of the Huizachal Canyon, has been delimited the formation to the Toarcian stage, being the regional equivalent of the Moroccan Azilal Formation. Deposits of Late Triassic Age referred to this unit have been reclassified in a new formation, El Alamar Formation. In North America, La Boca Formation was found to be a regional equivalent of the Eagle Mills redbeds of southern United States, the Todos Santos Formation of southern Mexico and the Barracas Group of the Sonora desert region.
The El Gallo Formation is a geological formation in Mexico whose strata date back to the Late Cretaceous, Campanian epoch, specifically dated to 75.21 ± 0.07 Ma and 74.55 ± 0.09 Ma. Dinosaur remains are among the fossils that have been recovered from the formation.
The Cerro del Pueblo Formation is a geological formation in Coahuila, Mexico whose strata date back to the Late Cretaceous. 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.
Nursallia is an extinct genus of pycnodontid ray-finned fishes, ranging from the Late Cretaceous period until its extinction during the Eocene.
Archaeoniscus is a genus of prehistoric isopods that first appeared during the Bajocian stage of the Middle Jurassic. It is a widespread genus with a paleogeographic distribution encompassing the continental margin environments of the central Atlantic Ocean and the western Tethys Ocean. Fossils of Archaeoniscus suggest that this genus lived in diverse aquatic habitats, including the marine, paralic, and freshwater environments. While earlier descriptions suggested that it may have had an ectoparasitic association with fishes, some researchers argue that at least two species, A. aranguthyorum and A. coreaensis, lived a benthic free-living lifestyle based on morphological characteristics that are either unsuitable for or unrelated to parasitic behavior.
Araripichthys is an extinct genus of ray-finned fish that lived from the Aptian to Coniacian stages of the Cretaceous period. The genus is named after the Araripe Basin, where it was found in the Crato and Santana Formations. Other fossils of the genus have been found at Goulmima in Morocco, the Tlayua Formation of Mexico and the Apón Formation of Venezuela.
Tarpons are fish of the genus Megalops. They are the only members of the family Megalopidae. Of the two species, one is native to the Atlantic, and the other to the Indo-Pacific Oceans.
Pamizinisaurus is a genus of sphenodontian reptile known from Lower Cretaceous (Albian) Tlayúa Formation of Mexico. A crushed skeleton of a juvenile reptile was found in Tlayua Quarry, in central Mexico. It was named Pamizinsaurus tlayuaensis by Reynoso in 1997, after the name of the quarry of which it was found. Its skull length is 16 millimetres (0.63 in). The fossil was covered in small round osteoderms that could have protected it from predators.
Eucommia constans is an extinct species of flowering plant in the family Eucommiaceae. Eucommia is a genus of small trees now native to China, with a fossil record that shows a much wider distribution. E. constans is known from fossil fruits found in Miocene to Pleistocene deposits of east-central Mexico. E. constans is one of five described fossil species from North America assigned to the modern genus Eucommia. The other species are E. eocenica, E. jeffersonensis, E. montana, and E. rowlandii.
Cipactlichthys is a genus of extinct holostean fish from the Lower Cretaceous of Mexico. The only known species is Cipactlichthys scutatus.
The Smeltertown Formation is a geologic formation in New Mexico, which is particularly well exposed at Cerro de Cristo Rey near El Paso, Texas. It preserves fossils dating back to the early Cretaceous period.
The Cintura Formation is a geologic formation in the northeastern Sonora of Arizona and Mexico. It preserves fossils dating back to the Cretaceous period.
The Sierra Madre Formation is a geologic formation in Chiapas state, southern Mexico. It consists of marine dolomites and limestones. The formation dates to the Middle Cretaceous, spanning from the Aptian of the Early to the Cenomanian of the Late Cretaceous.
The Olmos Formation is a geologic formation in Mexico. It preserves fossils of plants, hadrosaurs, ceratopsians, tyrannosaurs and the turtle Palauchelys dating back to the Cretaceous period.
The El Doctor Formation is a geologic formation in Mexico. It preserves fossils dating back to the Albian and Cenomanian stages of the Cretaceous period.
Ankylosphenodon is an extinct species of sphenodontian known from Tepexi de Rodriguez, Mexico. It is known from Early Cretaceous sedimentary deposits from the Tlayua formation.
Armigatus is an extinct genus of clupeomorph fishes belonging to the order Ellimmichthyiformes. These fishes lived in the Cretaceous ; their fossil remains have been found in Mexico, Croatia, the Middle East and North Africa, suggesting the genus ranged across the Tethys Sea.