The search for dinosaurs in New York State presents a unique challenge, as the geological record differs significantly from the fossil-rich badlands of the American West. New York’s history of dinosaur life is recorded not primarily in bones, but in the impressions left behind by their feet. The evidence consists almost entirely of trace fossils, or ichnofossils, which provide direct testimony of the creatures that walked across the ancient landscape during the Mesozoic Era.
The Geological Context of New York’s Mesozoic Era
Much of New York State is covered by rock layers that predate or postdate the Age of Dinosaurs, making skeletal remains exceedingly rare. The state’s rock record is generally composed of very old Paleozoic or much younger Cenozoic deposits. However, a specific sliver of Mesozoic rock exists in the southeastern portion of the state near the New Jersey border, within the Newark Supergroup.
This geological formation is part of a vast system of rift basins that formed when the supercontinent Pangea began to break apart (Late Triassic and Early Jurassic periods, 220 to 190 million years ago). The environment within these basins was a rift valley, dominated by large, cyclical freshwater lakes and broad floodplains. The sedimentary rocks, including the Passaic, Feltville, and Towaco Formations, were deposited in these low-energy environments.
These ancient lake beds and mudflats provided the perfect conditions for preserving tracks, as the fine-grained sediment retained the shape of a foot before being covered by subsequent layers. While excellent for track preservation, the conditions were less favorable for the long-term fossilization of bones, which are often eroded away or remain buried deep underground.
Primary Evidence: The Age of Dinosaur Footprints
The dinosaur evidence found in the Newark Supergroup consists of ichnofossils, or trace evidence of life, such as tracks, burrows, or coprolites. These fossils are particularly concentrated around the Triassic-Jurassic boundary, a period marked by a mass extinction event, providing a unique window into dinosaur life before and after this global upheaval.
Paleontologists use specific ichnogenus names to classify these tracks, distinct from the genus names given to skeletal remains. This convention is necessary because it is impossible to definitively link a single footprint to a single dinosaur species. The most common ichnogenus names found are Grallator and Eubrontes, signifying different sizes of bipedal dinosaurs.
The analysis of a trackway reveals details about the trackmaker, including its size, speed, gait, and social behavior. The distance between steps and the depth of the impression allow scientists to estimate the dinosaur’s hip height and weight. Parallel trackways suggest that some early dinosaurs may have moved in groups, providing behavioral insights not available from isolated bones.
Confirmed and Suggested Dinosaur Types
The footprints left in the Newark Supergroup confirm the presence of at least three major groups of dinosaurs in the New York region during the Early Mesozoic. The most abundant tracks belong to the ichnogenus Grallator. These are small, three-toed prints (four to eight inches long) created by small, bipedal theropods, or meat-eating dinosaurs, likely similar in size to Coelophysis.
A second, much larger theropod is represented by the ichnogenus Eubrontes, with tracks measuring up to 18 inches long. These substantial prints indicate the presence of medium to large predatory dinosaurs, possibly reaching 15 to 20 feet in length, comparable to Dilophosaurus. The prevalence of both Grallator and Eubrontes suggests that theropods were dominant in the local ecosystem.
The third group of dinosaurs is represented by tracks like Anomoepus, made by ornithischians, or “bird-hipped” dinosaurs, who were typically herbivores. Anomoepus tracks are often smaller and sometimes show impressions from a hand, suggesting the dinosaur could walk on all four limbs at times. A few isolated, non-diagnostic bone fragments have also been found in the region, reinforcing the footprint evidence of these early dinosaur lineages.
The Geological Context of New York’s Mesozoic Era
Much of New York State is covered by rock layers that predate or postdate the Age of Dinosaurs, which is why skeletal remains are exceedingly rare. The state’s rock record is generally composed of very old Paleozoic formations or much younger Cenozoic deposits. However, a specific sliver of Mesozoic rock exists, primarily in the southeastern portion of the state near the New Jersey border, within what is known as the Newark Supergroup.
This geological formation is part of a vast system of rift basins that formed when the supercontinent Pangea began to break apart, spanning the Late Triassic and Early Jurassic periods, roughly 220 to 190 million years ago. The environment within these basins was a rift valley, dominated by large, cyclical freshwater lakes and broad floodplains. The sedimentary rocks, which include the Passaic, Feltville, and Towaco Formations, were deposited in these low-energy environments.
These ancient lake beds and mudflats provided the perfect conditions for preserving tracks, as the fine-grained sediment would retain the shape of a foot before being covered and protected by subsequent layers. Although this environment was excellent for track preservation, the conditions were less favorable for the long-term fossilization of bones, which are often eroded away or remain buried deep underground. This geological circumstance explains why New York’s dinosaur record is a story told in footprints.
Primary Evidence: The Age of Dinosaur Footprints
The dinosaur evidence found in New York and the surrounding Newark Supergroup is categorized as ichnofossils, meaning trace evidence of life, such as tracks, burrows, or coprolites, rather than body fossils like bones or teeth. These ichnofossils are particularly concentrated around the critical time known as the Triassic-Jurassic boundary, a period marked by a mass extinction event. The tracks provide a unique window into the life of dinosaurs immediately before and after this global upheaval.
Paleontologists use specific ichnogenus names to classify these tracks, which are distinct from the genus names given to skeletal remains. This naming convention is necessary because it is impossible to definitively link a single footprint to a single dinosaur species. Two of the most common ichnogenus names found are Grallator and Eubrontes, which signify different sizes of bipedal dinosaurs.
The analysis of a trackway reveals rich details about the trackmaker, including its size, speed, gait, and even social behavior. For example, the distance between steps and the depth of the impression allow scientists to estimate the dinosaur’s hip height and weight. Parallel trackways suggest that some of these early dinosaurs may have moved in groups, providing early behavioral insights not available from isolated bones.
Confirmed and Suggested Dinosaur Types
The footprints left in the Newark Supergroup confirm the presence of at least three major groups of dinosaurs in the New York region during the Early Mesozoic. The most abundant tracks belong to the ichnogenus Grallator, which are small, three-toed prints typically measuring four to eight inches long. These tracks were created by small, bipedal theropods, or meat-eating dinosaurs, likely similar in size and form to the well-known Coelophysis.
A second, much larger theropod is represented by the ichnogenus Eubrontes, with tracks that can measure up to 18 inches long. These substantial prints indicate the presence of medium to large predatory dinosaurs, possibly reaching 15 to 20 feet in length, comparable to a species like Dilophosaurus. The prevalence of both Grallator and Eubrontes tracks suggests that theropods were dominant in the local ecosystem.
The third group of dinosaurs is represented by tracks like Anomoepus, which were made by ornithischians, or “bird-hipped” dinosaurs, who were typically herbivores. Anomoepus tracks are often smaller and sometimes show impressions from a hand, suggesting the dinosaur could walk on all four limbs at times. While the evidence is overwhelmingly trace-based, a few isolated, non-diagnostic bone fragments have been found in the region, reinforcing the footprint evidence of these early dinosaur lineages.