"Eterna" takes her name from the Latin aeternus, timeless or everlasting. Chosen to evoke the skull’s survival through deep geological time and its remarkable state of preservation. Her journey from the age of the dinosaurs to the present is a remarkable one.

After extensive prospecting work, combined with detailed field surveys and mapping, the bones of Triceratops were discovered and excavated in South Dakota. Paleontologists then carefully removed the surrounding layers of rock and sediment, freeing the fossils from the matrix that had encased them for millions of years.
Once the plaster jacket had hardened, the fossil was carefully lifted, cushioned, and transported to the laboratory. There, the plaster and field materials were meticulously removed, and fragile fossils were stabilized using specialized adhesives or resins. Missing or damaged parts were reconstructed for display, and detailed records, photographs, and scans were created for research (available on request).

Eterna is a remarkably well-preserved, near-complete skull of Triceratops and unearthed from the Late Cretaceous formations of South Dakota. Its distinctive proportions and horn structure, especially the prominent, forward-curving nasal horn, firmly identify it as Triceratops horridus. The horns of this specimen project in a way rarely observed in mounted Triceratops, striking an unusual visual pose while remaining anatomically accurate. The left horn exhibits slight flattening from the fossilization proccess, subtly lowering its profile and shaping the specimen’s distinctive appearance. The arrangement of the supraorbital horns, along with the absence of epiparietal and episquamosal ornamentation, confirms that Eterna was an adult individual. Compared to fully mature individuals, the bones are somewhat smaller, and the skull is more elongated along the craniocaudal axis, lacking the robust proportions typical of adult Triceratops. The preserved parietal bones are notably flat, unlike the upward-curving frills commonly seen in other specimens. This subdued, lower frill morphology supports the hypothesis of sexual dimorphism in Triceratops, with females potentially displaying less pronounced cranial ornamentation. Collectively, these features suggest the specimen may belong to a female of the species.

Triceratops horridus (Marsh, 1889) is one of the most iconic dinosaurs of the Late Cretaceous, instantly recognized by its three horns, massive frill, and powerful build. First described by Othniel Charles Marsh from fossils in Wyoming’s Lance Formation, it was initially named Ceratops horridus before being established later that year as the type species of the genus Triceratops. Defining features of the Ceratopsidae, such as a beak-like mouth, prominent frontal horns, broad parietal frill, and epoccipital bones, are clearly expressed in Triceratops. Its exceptionally rich fossil record, particularly of skulls at different growth stages, reveals significant changes in horn and frill morphology through ontogeny, likely linked to display, species recognition, and social behaviour. As a highly specialized herbivore, Triceratops possessed slicing teeth adapted for processing tough vegetation, representing one of the most advanced feeding systems among dinosaurs. Evidence suggests that Triceratops horridus gradually evolved into Triceratops prorsus toward the end of the Cretaceous. Ongoing studies of its bone microstructure continue to refine our understanding of Ceratopsid growth, development, and evolutionary biology, ensuring Triceratops horridus remains central to dinosaur research.