An aptychus is a type of marine fossil. It is a hard anatomical structure, a sort of curved shelly plate, now understood to be part of the body of an ammonite. Paired aptychi have, on rare occasions, been found at or within the aperture of ammonite shells. The aptychus was usually composed of calcite, whereas the ammonite shell was aragonite.
Dakosaurus is an extinct genus of crocodylomorph within the family Metriorhynchidae that lived during the Late Jurassic and Early Cretaceous. It was large, with teeth that were serrated and compressed lateromedially. The genus was established by Friedrich August von Quenstedt in 1856 for an isolated tooth named Geosaurus maximus by Theodor Plieninger in 1846. Dakosaurus was a carnivore that spent much, if not all, its life out at sea. The extent of its adaptation to a marine lifestyle means that it is most likely that it mated at sea, but since no eggs or nests have been discovered that have been referred to Dakosaurus, whether it gave birth to live young at sea like dolphins and ichthyosaurs or came ashore like turtles is not known yet. The name Dakosaurus means "biter lizard", and is derived from the Greek dakos ("biter") and σαῦρος -sauros ("lizard").
Geosaurus is an extinct genus of marine crocodyliform within the family Metriorhynchidae, that lived during the Late Jurassic and the Early Cretaceous. Geosaurus was a carnivore that spent much, if not all, its life out at sea. No Geosaurus eggs or nests have been discovered, so little is known of the reptile's lifecycle, unlike other large marine reptiles of the Mesozoic, such as plesiosaurs or ichthyosaurs which are known to give birth to live young out at sea. Where Geosaurus mated, whether on land or at sea, is currently unknown. The name Geosaurus means "Mother of Giants lizard", and is derived from the Greek Ge- and σαῦρος -sauros ("lizard"). The name Geosaurus was established by the French naturalist Georges Cuvier in 1824.
Muzquizopteryx is a genus of nyctosaurid pterodactyloid pterosaur from the Late Cretaceous period of what is now Coahuila, Mexico.
Cricosaurus is an extinct genus of marine crocodyliforms of the Late Jurassic. belonging to the family Metriorhynchidae. The genus was established by Johann Andreas Wagner in 1858 for three skulls from the Tithonian of Germany. The name Cricosaurus means "Ring lizard", and is derived from the Greek Krikos- ("ring") and σαῦρος -sauros ("lizard"). It was a relatively small reptile, with C. suevicus and C. araucanensis measuring 2 m (6.6 ft) and 3.2 m (10 ft) in total body length, respectively.
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.
Amphekepubis is a dubious genus of mosasaur from the Late Cretaceous of Mexico. Their remains correspond to the holotype specimen UM VP 509, a partial skeleton preserved in three dimensions, comprising the pelvic area, hind limb bones and nine caudal vertebrae, found in the east of Monterrey, in the state of Nuevo Leon, which come from marine sediments (claystones) apparently from the San Felipe Formation, which corresponds to the boundary between the ages of Coniacian and Santonian in the early Late Cretaceous. Amphekepubis is classified within the Mosasaurinae subfamily of mosasaurs.
The Solnhofen Limestone or Solnhofen Plattenkalk is a collective term for multiple Late Jurassic lithographic limestones in southeastern Germany, which is famous for its well preserved fossil flora and fauna dating to the late Jurassic (Kimmeridgian-Tithonian). The paleoenvironment is also often referred to as the Solnhofen Archipelago. The Solnhofen Archipelago was located at the northern edge of the Tethys Ocean as part of a shallow epicontinental sea and is firmly a part of the Mediterranean realm.
The "Monster of Aramberri", also nicknamed in the scientific literature as the Aramberri pliosaur or the Aramberri specimen, is an informal name given to UANL-FCT-R2, a fossil skeleton of a very large pliosaur of which the first remains were discovered during the 1980s near the town of Aramberri, in Nuevo León, Mexico. The specimen was first interpreted as a dinosaur in 1988, before later inspections re-identified it as a marine reptile belonging to the family Pliosauridae. Initially, two concretions only containing the animal's fossils were discovered, with one of the two—containing the fossils of a rostrum and teeth—later noted as lost in the first in-depth re-identification of the specimen in 2003. During the early 2000s, a new excavation campaign unearthed several additional fossils of the animal, in which some of them were subsequently sent to Karlsruhe State Museum of Natural History, Germany, to be prepared, before returning them in 2012 to the Autonomous University of Nuevo León, where they are mainly stored. Another significant portion of the fossils are currently stored in the Desert Museum of Saltillo.
This list of fossil arthropods described in 2013 is a list of new taxa of trilobites, fossil insects, crustaceans, arachnids and other fossil arthropods of every kind that have been described during the year 2013. The list only includes taxa at the level of genus or species.
This list, 2013 in molluscan paleontology, is a list of new taxa of ammonites and other fossil cephalopods, as well as fossil gastropods, bivalves and other molluscs that have been described during the year 2013.
The La Casita Formation is a geologic formation in Mexico. It preserves fossils dating back to the Kimmeridgian to lowermost Berriasian. It is laterally equivalent to the La Caja Formation and the Pimienta Formation. The ichthyosaurs Jabalisaurus and Acuetzpalin are known from the formation, as well as the metriorhynchid Dakosaurus and indeterminate pliosaurs.
The Pimienta Formation is a geologic formation in Mexico. It preserves fossils dating back to the Tithonian-Berriasian. The formation is considered laterally equivalent to the La Casita Formation. The Metriorhynchid Cricosaurus vignaudi is known from the formation.
The Artemisa Formation is a geologic formation in western Cuba. It preserves mainly ammonite fossils dating back to the Late Oxfordian to Tithonian period. The formation is divided into two members; La Zarza and Sumidero Members. Most of the formation was deposited in deeper marine conditions.
Zapata Formation is a sedimentary formation of Lower Cretaceous age in the Magallanes or Austral Basin of Argentina and Chile. Much of the formation is folded and faulted as consequence of the Andean orogeny. In outcrops of the Zapata Formation near Torres del Paine, the ichthyosaur genus Myobradypterygius has been found.
Laevapetchyus is a genus of ammonites.
Acuetzpalin is an extinct genus of platypterygiine ophthalmosaurid ichthyosaur found in the Kimmeridgian La Casita Formation in Mexico. It is known from a partial skeleton, of which the skull is surprisingly well preserved. Its length is estimated to have been more than 3.1 metres (10 ft) long, considering the missing parts of the holotype. It was the first ichthyosaur described in 2020 and the first new ichthyosaur genus described since 2017.
Parrassaurus is an ophthalmosaurid ichthyosaur from the late Jurassic La Caja Formation of Mexico named in 2021. Parrassaurus includes one species, Parrassaurus yacahuitztli. The type specimen was around 5 metres (16 ft) long.
Jabalisaurus is an ophthalmosaurid ichthyosaur from the Late Jurassic La Caja Formation of Mexico. It contains a single species, Jabalisaurus meztli.
Mexico 
