Dinosaurs in New Mexico
Above: A cast of the Cretaceous horned dinosaur Pentaceratops from northwestern New Mexico on display in the museum's Seacoast Hall. Sponsored by Bank of America.
Dinosaurs lived in New Mexico between 225 and 66 million years ago. These 159 million years encompass the Late Triassic and the entire Jurassic and Cretaceous periods of geologic history. New Mexico is unique in that it preserves both body fossils and trace fossils of Triassic, Jurassic, and Cretaceous dinosaurs. Body fossils are actual pieces of an animal, such as fossil bones and teeth. Trace fossils are "fossilized behavior" and can include footprints, skin impressions, coprolites, and egg shells.
The fossil record of New Mexico covers nearly the entire timespan of the dinosaurs, from their first appearance during the Late Triassic until their extinction at the end of the Cretaceous.
Dinosaur fossils have been found across all of New Mexico except for the southeastern corner of the state. Dinosaur fossils were first collected in New Mexico during the 1880s, and the state's dinosaurs now are displayed in many museums throughout the world. Facilities in New Mexico that display dinosaur fossils include the New Mexico Museum of Natural History and Science, the Geology Museum of the University of New Mexico, the Ruth Hall Museum of Paleontology at Ghost Ranch near Abiquiu, Clayton Lake State Park near Clayton, the Mesalands Dinosaur Museum in Tucumcari, and the Museum of the New Mexico Bureau of Mines and Mineral Resources in Socorro. Of these, the New Mexico Museum of Natural History and Science holds the most dinosaurs on exhibit.
Dinosaurs became extinct 66 million years ago at the end of the Cretaceous Period. The Late Cretaceous dinosaurs from the San Juan Basin were some of the last to have lived on Earth. They are world famous because of the information they provide scientists about the cause of dinosaur extinction.
Above: Skin impression of a Cretaceous hadrosaur on display in the museum's New Mexico's Seacoast exhibit.New Mexico's Triassic Dinosaurs
New Mexico has the best record of Triassic dinosaurs of any of the United States. This record includes skeletons of Coelophysis, teeth of Revueltosaurus, bones of Eucoelophysis, fragmentary skeletons of other dinosaurs, and tracks of many dinosaurs. The New Mexican record is particularly significant because some of these dinosaurs are among the oldest known in the world. Additionally, Coelophysis, the official state fossil, is one of the best-preserved dinosaurs in terms of both completeness and abundance.
Hundreds of skeletons of Coelophysis were discovered at Ghost Ranch (Rio Arriba County) during the 1940s. This two- to three-meter-long, meat-eating dinosaur was one of the first dinosaurs on Earth and is the best-known Late Triassic dinosaur. The museum is presently preparing its block from the Coelophysis quarry for exhibit. The block holds dozens of well-preserved skeletons of Coelophysis and other animals.
Above: An exquisitely preserved juvenile skull of Coelophysis under preparation at the museum. Scale bar is in mm.
In 1988, scientists at the New Mexico Museum of Natural History and Science discovered a new Late Triassic dinosaur near Tucumcari. They named this two-meter-long, plant-eating dinosaur Revueltosaurus, after Revuelto Creek in Quay County. Later museum scientists discovered a second species of Revueltosaurus from central New Mexico and eastern Arizona.
Above: Tooth of Revueltosaurus callenderi in two different views. The actual teeth are only 1/3 in (8.3 mm) tall.
Above: Tooth of Revueltosaurus hunti in two different views. The scale bar is 1 mm (1/25 in) long, so the tooth is 7.6 mm tall.
The museum is also home to Eucoelophysis, a dinosaur extremely similar to Coelophysis found in slightly older rocks in Rio Arriba County.
Above: Fragmentary skull of Eucoelophysis from the Snyder quarry in northern New Mexico. Scale bar is 5 cm (~2 in) long.
Eastern New Mexico is home to dozens of footprint sites, which include tracks of theropod dinosaurs (Grallator), prosauropods (Pseudotetrasauropus) and possibly even Triassic sauropods (Tetrasauropus).
Other Late Triassic dinosaurs known from New Mexico are only represented by isolated bones and teeth. Much more study and scientific collecting of New Mexico's Triassic dinosaurs remains to be done!
New Mexico's Jurassic DinosaursAll Jurassic dinosaur bones from New Mexico are 140-150 million years old, and their fossils are found only in the northern half of the state. This is where rocks of this age, called the Morrison Formation are exposed.
New Mexico is home to two giant Jurassic dinosaurs: Seismosaurus and Saurophaganax.
SeismosaurusOne of the world's longest dinosaurs, Seismosaurus, was discovered near San Ysidro (Sandoval County) in 1979. This 33-meter-long sauropod resembled a huge version of the better-known Diplodocus. Both the actual fossil and a life-sized skeletal reconstruction of Seismosaurusis on display in the New Mexico Museum of Natural History and Science's new Age of Giants Hall which opened on August 7, 2004.
A single vertebra from Seismosaurus in anterior (head-on) view. The scale bar is 1 ft (~300 mm) long.
Saurophaganax and the Peterson quarry
New Mexico's best Morrison Formation dinosaur quarry is the Peterson quarry, located on BLM land in central New Mexico. A father-son team, the Petersons first discovered the site in the 1960s. Since 1989, they have led dozens of excavations at the site, pouring in thousands of volunteer hours to excavate almost 70 jackets containing dinosaur bones and teeth. The most dramatic specimen from the Peterson quarry is a partial skeleton of the giant (40 ft/12 m long theropod Saurophaganax. This partial skeleton and a full-size mounted cast is on display in the New Mexico Museum of Natural History and Science's new Age of Giants Hall which opened on August 7, 2004.
Quarry map compiled by Ron and Rod Peterson of the Peterson quarry in central New Mexico. Most of the Saurophaganax bones came out of grid squares G-I/11-14.
NMMNH volunteers and their vehicles at the Peterson quarry in central New Mexico.New Mexico's Cretaceous Dinosaurs
The oldest Cretaceous dinosaurs in New Mexico are known from 100-million-year-old footprints in Harding and Union counties. These are footprints of ornithopod dinosaurs closely related to duck-billed dinosaurs. A representative slab from Mosquero Creek is on display outside the museum. The footprints are best seen in place at Clayton Lake state Park, where an exhibit explains the more than 500 dinosaur footprints exposed at the dam spillway. Another trackway will lead from the new Jurassic hall to the New Mexico's Seacoast in the museum.
Above: Cretaceous ornithopod tracks (Caririchnium) from northeastern New Mexico on display north of the main entrance of the museum. This is the only dinosaur fossil on display to the public 24 hours a day 365 days a year in New Mexico. Ruler is 1 ft (300 mm) long.
New Mexico's best-known dinosaurs come from 75-66 million-year-old rocks in the San Juan Basin of the northwestern part of the state. These Late Cretaceous dinosaur fossils are particularly abundant in the Bisti/De-na-zin Federal Wilderness Areas south of Farmington. The museum works closely with the United States Bureau of Land Management (BLM) and obtains special permits to excavate and house these fossils.
The Late Cretaceous dinosaurs from the San Juan Basin lived in the river floodplains and jungles near a seacoast that was then located in northwestern New Mexico. This seacoast and its dinosaurs are featured in New Mexico's Seacoast, an exhibit at the Museum.
The duck-billed dinosaurs Parasaurolophus and Kritosaurus and the horned dinosaur Pentaceratops were the most common dinosaurs living in northwestern New Mexico during the Late Cretaceous. An extremely important specimen of Parasaurolophus, discovered in 1995, is on display at the museum.
Photograph of the skull of the crestedhadrosaur Parasaurolophus on display in the New Mexico's Seacoast hall of the museum.Link to Parasaurolophus Sound page
Also present were Albertosaurus, a nine-meter-long, close relative of Tyrannosaurus rex. North America's last sauropod dinosaur, Alamosaurus sanjuanensis, takes its name from Ojo Alamo, a spring south of Bloomfield, and the San Juan Basin.
Blackhawk helicopters of the New Mexico Army National Guard airlifting out the "Bisti Beast" from the Bisti/De-na-zin Wilderness Area.
Late Cretaceous dinosaurs also have been collected in New Mexico near Deming and east of Elephant Butte Reservoir.
The "Elephant Butte T. rex" on display in the New Mexico's Seacoast Hall at the museum.
