At the Zanno Lab we emphasize transparency and transdisciplinary research.
Our science blends field discoveries with quantitative approaches and frontier technologies to reconstruct the biodiversity, evolution, and paleobiology of dinosaurs—from transitions in reproduction, diet, and growth, to the impact of climate change on Cretaceous terrestrial ecosystems.
Come visit us at the world's only open-access paleontology lab—the SECU DinoLab at the North Carolina Museum of Natural Sciences in downtown Raleigh.
Newly Published Science
Zanno LE and Napoli JG. 2025. Nanotyrannus and Tyrannosaurus co-existed at the close of the Cretaceous. Nature https://doi-org.prox.lib.ncsu.edu/10.1038/s41586-025-09801-6
Abstract Tyrannosaurus rex ranks among the most comprehensively studied extinct vertebrates and a model system for dinosaur paleobiology. As one of the last surviving non-avian dinosaurs, Tyrannosaurus is a crucial datum for assessing terrestrial biodiversity, ecosystem structure, and biogeographic exchange immediately preceding the end-Cretaceous mass extinction—one of Earth’s greatest biological catastrophes. Paleobiological studies of Tyrannosaurus, including ontogenetic niche partitioning, feeding, locomotor biomechanics and life history have drawn upon an expanding skeletal sample comprising multiple hypothesized growth stages—and yet the Tyrannosaurus hypodigm remains controversial. A key outstanding question relates to specimens considered to exemplify immature Tyrannosaurus, which have been argued to represent the distinct taxon Nanotyrannus. Here, we describe an exceptionally well-preserved, near somatically mature tyrannosaur skeleton (NCSM 40000) from the Hell Creek Formation that shares autapomorphies with the holotype specimen of N. lancensis. We couple comparative anatomy, longitudinal growth models, observations on ontogenetic character invariance, and a novel phylogenetic dataset to test the validity of Nanotyrannus, demonstrating conclusively that this taxon is distinguishable from Tyrannosaurus, sits outside Tyrannosauridae, and unexpectedly contains two species—N. lancensis and N. lethaeus, sp. nov. Our results prompt a re-evaluation of dozens of existing hypotheses based on currently indefensible ontogenetic trajectories. Finally, we document at least two co-occurring, ecomorphologically distinct genera in the Maastrichtian of North America, demonstrating that tyrannosauroid alpha diversity was thriving within one million years of the end-Cretaceous extinction.
Zanno LE. 2025. Dinosaur diversity before the asteroid. Science Oct 23;390(6771):332-333. doi: 10.1126/science.aeb5725. Epub 2025 Oct 23. PMID: 41129655.
Abstract Few phenomena in Earth’s history have been as widely popularized as the mass extinction of non-avian dinosaurs. Yet, the disappearance of such awe-inspiring animals has roused more than public fascination—it has spurred enduring scientific debate. Paleontologists largely agree that an asteroid dealt the final blow to non-avian dinosaurs, but their susceptibility to annihilation when the asteroid plummeted to Earth remains an open question. On page 400 of this issue, Flynn et al. (1) reveal that a well-known rock layer in northwestern New Mexico captures a rare glimpse into the last days of the dinosaurs. Their findings markedly increase the number of dinosaur species known to have roamed Earth ~400,000 years before the asteroid’s impact, challenging the idea that weakened ecosystems played a role in their demise.
Chinzorig T, Takasaki R, Yoshida J, Tucker RT, Buyantegsh B, Mainbayar B, Tsogtbaatar K, Zanno LE. 2025. A Domed Pachycephalosaur From the Early Cretaceous of Mongolia. Nature 2025 Sep 17:1-8
Abstract The dome-headed pachycephalosaurians are among the most enigmatic dinosaurs. Bearing a hypertrophied skull roof and elaborate cranial ornamentation, members of the clade are considered to have evolved complex sociosexual systems1,2,3. Despite their importance in understanding behavioural ecology in Dinosauria, the absence of uncontested early diverging taxa has hindered our ability to reconstruct the origin and early evolution of the clade4,5,6,7. Here we describe Zavacephale rinpoche gen. et sp. nov., from the Lower Cretaceous Khuren Dukh Formation of Mongolia, the most skeletally complete and geologically oldest pachycephalosaurian discovered globally. Z. rinpoche exhibits a well-developed frontoparietal dome and preserves the clade’s first record of manual elements and gastroliths. Phylogenetic analysis recovered Z. rinpoche as one of the earliest diverging pachycephalosaurians, pushing back fossil evidence of the frontoparietal dome by at least 14 Myr and clarifying macroevolutionary trends in its assembly. We found that the earliest stage of dome evolution occurred by means of a frontal-first developmental pattern with retention of open supratemporal fenestra, mirroring proposed ontogenetic trajectories in some Late Cretaceous taxa. Finally, intraskeletal osteohistology of the frontoparietal dome and hindlimb demonstrate decoupling of sociosexual and somatic maturity in early pachycephalosaurians, with advanced dome development preceding terminal body size.
Tucker RT, Venter KE, Lana C, Roberts EM, Chinzorig T†, Tsogtbaatar K, Chiarenza AA, Zanno LE. 2025. U-Pb calcite age dating of fossil eggshell, an accurate deep-time geochronometer. Communications Earth & Environment 6, 872. https://doi-org.prox.lib.ncsu.edu/10.1038/s43247-025-02895-w
Abstract Earth’s sedimentary rock record is the primary archive for biotic, environmental, and climatic trends in deep time. Reconstructing these patterns requires a high-resolution geochronologic framework. This remains a significant challenge for many terrestrial ecosystems and an acute problem for some of the world’s most important Mesozoic and Cenozoic fossil records. Overcoming this issue requires frontier approaches, such as directly dating fossils, long considered untenable. Here, we test the reliability of novel LA-ICP-MS U-Pb calcite dating and elemental mapping of non-avian dinosaur eggshells to produce accurate “burial ages.” We directly dated fossilized dinosaur eggs recovered from the Western Interior Basin of North America, producing ages within 5% of high-precision ages from bracketing ash beds. We then directly dated dinosaur eggs from Upper Cretaceous strata within Mongolia’s famous yet poorly age-constrained Gobi Basin, providing the first radioisotopic age for these deposits. Geochemical data coupled with trace elemental mapping indicate early uptake of uranium (U) in non-avian dinosaur eggshells via sediment contact, consistent with findings from Quaternary avian eggs. Calcified eggs, having evolved over 250 million years ago, offers a promising experimental methodology for determining the age of globally distributed fossil assemblages and recovering temporal, environmental, and ecological data from a single fossil.
