In a remarkable breakthrough that reshapes our understanding of dinosaur ecology in northern Asia during the Early Cretaceous period, an international team of paleontologists has rediscovered and meticulously studied a long-lost dinosaur tracksite in the Saizhurakh region of northern Mongolia. Originally recorded some seventy years ago but subsequently lost due to sparse documentation and lack of continued investigation, the site has now yielded an exceptional ichnofauna demonstrating the coexistence of gigantic herbivorous sauropods and formidable carnivorous theropods on the same geological layer, dating back around 120 million years.
The researchers, hailing from the Institute of Paleontology at the Mongolian Academy of Sciences, the National University of Mongolia, and Okayama University of Science, commenced their expedition in 2024 with the aim of relocating the enigmatic site based on fragmented historical records. With invaluable assistance from local communities, they successfully pinpointed the location, enabling comprehensive paleontological and sedimentological surveys to be undertaken. This renewed focus culminated in a detailed multidisciplinary analysis culminating in a scientific publication in early 2026, providing the first substantiated evidence of large dinosaur presence in Mongolia during the Early Cretaceous.
This discovery is particularly significant because Mongolia has predominantly produced Late Cretaceous dinosaur fossils, typically dating between 70 and 90 million years ago, with Early Cretaceous fossils being rare and usually pertaining to smaller species. Previously, only modest specimens from genera such as Harpymimus, Psittacosaurus, Zavacephale, and Choyrodon had been documented, while no confirmed tracksites from the Early Cretaceous were known. Thus, the identification of a tracksite with footprints from giant titanosauriform sauropods and large theropods expands the temporal and ecological scope of dinosaur research in this part of Asia.
The tracksite lies within sedimentary layers of the Shinekhudag Formation, characterized by fine black clay sediments interspersed with thin sand deposits. These sediments accumulated on the floor of a sizable freshwater lake during the Early Cretaceous, and the presence of sandy layers suggests episodic drops in lake levels, exposing substrates suitable for track formation. Dinosaur footprints were impressed onto these temporarily exposed sandy surfaces, enabling remarkable preservation of their locomotor traces which provide glimpses of dinosaur behavior and habitat use.
Among the 31 dinosaur footprints documented, two sauropod trackways run parallel and overlap significantly, indicating intriguing behavioral implications. Both sauropods were enormous, herbivorous creatures, each exceeding 15 meters in length, with hind footprints roughly 70 centimeters long. The overlapping pathways strongly suggest that one individual followed the footsteps of another closely, perhaps as a strategy to conserve energy or navigate difficult terrain. Such behavior parallels that observed in modern elephants, hinting at complex social or migratory dynamics among these prehistoric giants.
Anatomical details preserved in the sauropod tracks reveal a unique combination of primitive and derived characteristics. The forelimb impressions include a medially projecting thumb claw—a basal trait—while also preserving soft tissue pads indicative of more advanced anatomical adaptations. Furthermore, the wide gauge of the trackways suggests a broad, outward stance during locomotion, consistent with titanosauriform sauropods, a major clade known for their colossal size and global distribution during the Mesozoic.
In addition to the sauropod prints, five distinct trackways attributed to large theropods have been documented, each exhibiting classic three-toed footprints with widely splayed digits. These carnivorous dinosaurs, measuring over eight meters in length, appear to have used the area independently, as the directions of their trackways show no coordinated movement or pack-like behavior. This contrasts with the social behaviors often attributed to certain theropod groups and implies solitary or loosely associated hunting strategies in this region during the Early Cretaceous.
The largest theropod footprint measures an impressive 57 centimeters, attesting to the massive size of apex predators inhabiting northern Mongolia at the time. While similar large theropod footprints have been known from contemporaneous Early Cretaceous localities in China, South Korea, and Japan, evidence from Mongolia and adjacent eastern Russia has been conspicuously absent until now. This discovery fills a crucial geographical gap and illustrates the expansive distribution of these formidable predators across Asia’s northern latitudes.
The paleoenvironment reconstructed from the sedimentary context and fossil finds portrays a warm, lacustrine ecosystem during a time when Earth experienced elevated global temperatures and vibrant floral diversification, including the rapid proliferation of angiosperms. These environmental factors likely influenced dinosaur dispersal and ecological niches, facilitating faunal exchanges between Asia and early North America. Mongolia’s positioning thus renders it a pivotal arena for unraveling biogeographic patterns and evolutionary trajectories linking the faunas of East Asia, Siberia, and North America.
Notably, the overlapping trackways of the two massive sauropods provide rare behavioral insights. The trailing individual’s nearly identical pathway and slower pace might suggest group cohesion, migratory behavior, or energy-efficient travel by following footsteps already compressed into the substrate. Such interpretations enrich our understanding of sauropod sociality and movement across varied terrains, complementing skeletal evidence with functional ichnological data.
This renewed scientific interest and careful investigation underscore the potential for further discoveries in the region. Adjacent to the site, gravelly sand layers might harbour skeletal remains awaiting excavation, which would grant unprecedented opportunities to correlate tracks with specific dinosaur taxa. The research team’s ongoing commitment to exploring nearby outcrops anticipates additional tracksites or fossils that could deepen understanding of Early Cretaceous dinosaur ecosystems in northern Mongolia.
The findings were formally reported in March 2026 through the reputable journal Ichnos, underscoring the importance of ichnology—the study of trace fossils—as a critical tool for paleontologists in reconstructing dinosaur life history beyond bones. This research not only illuminates Mongolia’s paleontological record but also invites reassessment of climate, biogeography, and ecosystem dynamics during a transformative epoch in Earth’s history.
By capturing evidence of both herbivorous and carnivorous dinosaurs cohabiting this lacustrine landscape, the study highlights a shared habitat where diverse dinosaurs thrived. This coexistence aids in constructing more nuanced ecological models and contributes to a global perspective on dinosaurian evolution and migration during the Early Cretaceous, setting a new benchmark for Asian dinosaur trace fossil studies.
Subject of Research: Dinosaur ichnofauna from the Lower Cretaceous Shinekhudag Formation in northern Mongolia
Article Title: A dinosaur ichnofauna from the Lower Cretaceous Shinekhudag Formation, Mongolia
News Publication Date: 19-Mar-2026
Web References:
http://dx.doi.org/10.1080/10420940.2026.2645024
Image Credits: Okayama University of Science
Keywords: Early Cretaceous, dinosaur tracksite, Mongolia, sauropod footprints, theropod footprints, Shinekhudag Formation, dinosaur behavior, titanosauriforms, paleoecology, ichnology, lacustrine sediments, dinosaur migration
