A fossil that sat unnoticed in a museum drawer for over a century has been identified as an entirely new dinosaur species. The skull fragment, originally misattributed to a long-snouted diplodocid, is now recognized as Athenar bermani, a dicraeosaurid sauropod from the Late Jurassic Morrison Formation in what is now eastern Utah.
The specimen, CM 26552, consists of a braincase and portions of the skull roof. It was collected in 1913 at Carnegie Quarry in Dinosaur National Monument and stored at the Carnegie Museum of Natural History in Pittsburgh. In a recent study, researchers reexamined the skull and found features incompatible with Diplodocus, prompting a reassessment that redefines its identity and evolutionary relationships within sauropods.
Led by Dr. John A. Whitlock, a paleontologist at Mount Aloysius College and the Carnegie Museum of Natural History, the project focused on how skull bones record the evolution of long-necked dinosaurs. Whitlock notes that Carnegie Museum holds crucial specimens for understanding diplodocoid cranial anatomy, yet CM 26552 had long served as the textbook braincase for Diplodocus — a misclassification that overlooked a different lineage.
What makes Athenar bermani distinctive
The name honors a musician and acknowledges earlier researchers who studied similar fossils. Unlike the towering giants like Diplodocus or Apatosaurus, Athenar belongs to the smaller dicraeosaurids, which have shorter necks and taller neural spines along their backs. Its skull exhibits a mosaic of traits seen in dicraeosaurids from South America and China, rather than those typical of Diplodocus. A particularly notable feature is a tiny bony tooth along a skull suture at the rear of the head, a detail that helps set Athenar apart. Other skull characteristics — such as openings in the braincase roof and a hook-shaped prong on the squamosal bone near the jaw joint — further support its reclassification.
Putting dicraeosaurids on the map
Dicraeosaurids were once thought to be largely confined to South America and a few African sites. Athenar bermani provides a solid North American example of this group and suggests that smaller sauropods were more widespread in the Late Jurassic than previously believed. The skull features observed in this fossil help paleontologists trace how bone structures evolved as dicraeosaurids migrated into new regions, shedding light on shifts in diet, habitat, and posture that informed their distinct evolutionary path from longer-necked relatives.
A bustling Jurassic landscape
Magnetostratigraphy has dated the Morrison Formation layer housing Athenar’s skull to roughly 151–150 million years ago, making Athenar one of the last long-necked dinosaurs known from this portion of the formation. At that time, the region featured a low-lying landscape with rivers, floodplains, and forests, and the Morrison Formation preserves a diversity of dinosaurs, including plant-eaters like Apatosaurus and Stegosaurus and theropods such as Allosaurus. The formation is renowned for its sauropod diversity, rivaling that of any other Jurassic-aged rock unit.
What we gain from this find
Even though Athenar bermani is known from a single skull fragment, that fragment carries meaningful clues about neural and vascular passageways and how its head compared with related species. This discovery underscores the importance of reexamining old collections; many museum specimens were labeled at times when fewer dinosaurs were known and fewer comparative tools existed. Modern methods — precise anatomical surveys and advanced imaging — can turn older fossils into fresh data.
In this case, a specimen once used to describe Diplodocus’s braincase has revealed a distinct, regionally spread cousin sharing its habitat. The study appears in Palaeontologia Electronica and highlights how reinterpreting existing fossils can reshape our understanding of dinosaur diversity and distribution.
For more engaging paleontology news and analysis, you can subscribe to the Earth newsletter or explore EarthSnap, a free app offering updates and features about dinosaur research.
