Camarasauridae

Lore & Background

Camarasauridae was named by Edward Drinker Cope in 1877, with Camarasaurus as its type genus. The family is defined as the clade containing all species more closely related to Camarasaurus supremus than Saltasaurus loricatus. Camarasaurus is the only taxon uncontroversially regarded as a valid genus, containing four species: C. grandis, C. lentus, C. lewisi, and C. supremus, though C. lewisi may represent a distinct genus, Cathetosaurus. Lourinhasaurus is regarded as a camarasaurid by most studies, though it has also been considered a basal eusauropod. Other possible members include Oplosaurus, known only from a tooth; Tehuelchesaurus, which has been placed in various positions and extends the family's distribution to South America (Gondwana); and Bellusaurus, known only from juvenile remains.

Reader's Guide

Camarasauridae occupies a significant position in sauropod evolution, typically regarded as belonging to Macronaria, one of the two major branches of Neosauropoda, where it occupies a basal position outside Titanosauriformes. However, some studies have found Camarasauridae to lie outside Neosauropoda, indicating ongoing phylogenetic uncertainty. The family's distribution was limited to the Laurasian continent during the Upper Jurassic, with most specimens discovered in the Morrison Formation of North America, though some from the African Tendaguru Formation have been speculated to belong to Camarasaurus, and the closely related Lourinhasaurus was found in Portugal. Dental microwear indicates camarasaurids had a narrow ecological niche breadth and likely frequently migrated in search of new food sources. In North America, they filled a similar niche to turiasaurs, while in Europe, where turiasaurs were present, the two groups occupied clearly distinct niches due to niche partitioning.

Did You Know?

• Camarasaurids had a short skull with an external narial diameter approximately 40% of the long-axis length of the skull.
• Camarasaurids were once thought to be limited to Laurasia, but possible members like Tehuelchesaurus from South America suggest a broader distribution, including Gondwana.