Dino-sized Success Story

Source Institution: Smithsonian National Museum of Natural History

Source Exhibit: David H. Koch Hall of Fossils - Deep Time

Source Url: https://naturalhistory.si.edu/visit/virtual-tour/current-exhibits/deep-time-virtual-tour-fossil-list

Source Kind: interpretive_topic_or_panel

Use: research inspiration only; SAGE will write original interpretation

Dossier Status: scientifically_enriched_concept_room_07

Plain Language Explanation: The Cretaceous lasted nearly 80 million years and contained many different dinosaur worlds. Ankylosaurs, hadrosaurs, ceratopsians, pachycephalosaurs, titanosaurs, dromaeosaurs and tyrannosaur relatives occupied a wide range of terrestrial roles. Their diversity changed through time and from continent to continent as seas divided landmasses, climates shifted and flowering plants transformed terrestrial ecosystems.

Evidence: Cretaceous fossil assemblages contain many specialized dinosaur groups with distinct skulls, teeth, armor, limbs and feeding adaptations.; North American dinosaur faunas changed substantially as the Western Interior Seaway expanded and later retreated.; Flowering plants appeared and diversified during the Cretaceous, reshaping terrestrial habitats and food webs.; Regional fossil records show that dinosaur diversity was not identical everywhere or constant through the period.

Examples From Collection: Saurornitholestes langstoni; Titanosauria indet.; Anodontosaurus lambei; Stegoceras validum; Gorgosaurus libratus; Euoplocephalus tutus; Prosaurolophus maximus; Centrosaurus apertus

Common Misconception: A generic picture containing every famous Cretaceous dinosaur does not represent one real ecosystem. Species separated by millions of years or thousands of kilometers did not necessarily encounter one another.

What Scientists Still Debate: Researchers continue to study how much apparent dinosaur diversity reflects true evolutionary patterns versus unequal rock exposure, collecting effort and preservation between regions and time intervals.

Sources: https://www.nps.gov/articles/000/cretaceous-period.htm; https://www.nps.gov/subjects/fossils/cretaceous-dinosaurs.htm; https://www.nps.gov/subjects/fossils/cretaceous-neighbors.htm; https://www.nps.gov/subjects/fossils/diversification-of-life.htm

Enrichment Method: SAGE original interpretive concept; Cretaceous ecosystems kept geographically and chronologically distinct; direct feeding evidence separated from functional inference; bird-dinosaur relationship represented phylogenetically