Dinosaurs of Mexico

The Unknown South of North America: The Ancient World of Southern Laramidia

For a long time, dinosaur research in North America centered on the western United States and Alberta, Canada. However, recent discoveries in northern Mexico are bringing about a dramatic shift.

The latest research reveals that strong "provincialism" existed within the continent of Laramidia. The fossil record of Mexico holds the key to unlocking the unique ecosystem of this "Southern Laramidia."

Coahuila: A Tropical Delta for Dinosaurs

The state of Coahuila in northern Mexico is often called the "Holy Land" of Mexican paleontology. In particular, the "Cerro del Pueblo Formation" in the southern part of the state preserves the ecosystem of the Campanian age (about 72.5 million years ago) in amazing condition.

This land was once a vast delta situated on the coastline of the Western Interior Seaway. The climate was tropical to subtropical, a humid environment where palms, ginger plants, and mangrove forests flourished. These lush evergreen plants filled the stomachs of giant herbivorous dinosaurs.

The Explosive Diversity of Hadrosaurs

Dominating the landscape of Late Cretaceous Mexico were the "duck-billed" hadrosaurs. While diversity was declining in the north during this period, multiple diverse genera coexisted and thrived in Mexico.

Sailed Forehead: Velafrons

Velafrons coahuilensis is a lambeosaurine dinosaur described in 2007. The genus name means "sailed forehead" (from Latin velum and frons), derived from the fan-shaped crest on its head.
Although the specimen discovered was a juvenile still growing, it had already reached a length of about 7.6 meters. It is estimated that adults would have exceeded 9 to 10.5 meters, making it one of the largest hadrosaurs in North America at the time.

Speaking Crest: Tlatolophus

Described in 2021, Tlatolophus galorum belongs to the tribe Parasaurolophini.
Its name combines the Nahuatl word for "word" (tlahtolli) and the Greek word for "crest" (lophus). It was named because the shape of its crest resembles a symbol representing "word" in Aztec manuscripts.
It possessed a long, hollow crest of about 1.3 meters and is thought to have communicated over long distances using low-frequency sounds.

Proof of Southern Diversity: Coahuilasaurus

Coahuilasaurus lipani, newly described in 2024, was identified as a new genus after re-examining fossils previously attributed to Kritosaurus.
It possessed a specialized saw-toothed structure on its snout (rostrum), thought to have evolved for eating tough, fibrous plants like palm leaves. This discovery revealed that all three major lineages—Kritosaurini, Lambeosaurini, and Parasaurolophini—coexisted in southern Laramidia.

Giant Tail: Magnapaulia

From Baja California state, Magnapaulia laticaudus, the largest lambeosaurine in North America, has been discovered.
Its total length may have reached up to 15 meters, and it is characterized by a very high and broad tail. There is a theory that it used this tail for swimming.

Evolution and Gigantism of Ceratopsians

Ceratopsians, represented by Triceratops, also underwent unique evolution in Mexico.

Largest Horns in History: Coahuilaceratops

Described in 2010, Coahuilaceratops magnacuerna is characterized by "massive horns," as its name suggests.
The length of the horns above its eyes reached about 1.2 meters, the largest among all known ceratopsians. Its total length is estimated at about 6.7 to 8 meters, making it a dominant herbivore in the ecosystem of that time.

Small Ceratopsian: Yehuecauhceratops

On the other hand, Yehuecauhceratops mudei, described in 2017, is a small ceratopsian with a length of about 3 meters.
It belongs to the subfamily Centrosaurinae and features a unique projection on the edge of its frill. The specific name honors the nickname (MUDE) of the "Museo del Desierto (Desert Museum)" which houses the fossil.

Theropods: Southern Tyrants and Strange Runners

Research on carnivorous dinosaurs (theropods) in Mexico is also revealing the bigger picture thanks to recent discoveries.

Labocania: Once a dinosaur of much mystery, the discovery of a new species in 2024 confirmed it as a tyrannosaurid (Teratophoneini) endemic to southern Laramidia. Unlike northern tyrannosaurs, it had a short, deep skull.

Paraxenisaurus: Described in 2020, this is the first deinocheirid dinosaur from North America. Unlike typical ornithomimosaurs, it had a robust, heavy build and is thought to have adapted to life in wetlands.

Tototlmimus: The first formal ornithomimid discovered in Mexico, found in the state of Sonora. Its name derives from "bird" (Tototl) in Nahuatl.

In Search of Lost Time: Michoacan and Chiapas

Mexican dinosaur fossils are not limited to the north. Important discoveries have also been reported from the southern states of Michoacan and Chiapas.

The Most Ancient Duck: Huehuecanauhtlus

From the state of Michoacan, a hadrosauroid from the Santonian age (about 85 million years ago), older than the Campanian, has been discovered: Huehuecanauhtlus tiquichensis.
Its name means "ancient duck" in Nahuatl. It is an important dinosaur that preserves the early form of hadrosaurs as they began to radiate in North America.

Present of Mexican Dinosaur Research

Currently, Mexico is in the midst of a paleontological "Renaissance."
The "Museo del Desierto (Desert Museum)" in Saltillo, Coahuila, is a center for research, offering skeletal exhibits based on the latest studies and views of research in glass-walled labs.
Also, the "Rincón Colorado Paleontological Zone" offers a "living fossil experience" where visitors can view actual fossil layers in the field.

Table: List of Major Mexican Dinosaurs