Galeamopus

Galeamopus was a long, slender diplodocine sauropod that inhabited North America during the Late Jurassic period, around 152 million years ago. For over a century, its fossils were classified as a species of Diplodocus until comprehensive phylogenetic analyses in 2015 demonstrated that it was a distinct genus. Measuring between 23 and 27 metres in length, Galeamopus possessed a whip-like tail, pillar-like legs, and an extraordinarily long neck. It is particularly valuable to palaeontologists because several well-preserved skulls have been recovered, which are exceedingly rare for diplodocids. These skulls reveal distinct differences in the braincase and snout shape compared to Diplodocus, indicating niche partitioning in feeding habits among Morrison sauropods.

Its genus name translates poetically to 'needing a helmet', honouring researcher Oliver P. Hay whose surname sounds like helmet in German.

Where and when

Galeamopus lived in the Late Jurassic, from 155 to 150 million years ago (Kimmeridgian age). Its remains come from United States, in the Morrison Formation.

The numbers

Length 25 m (estimates run from 23 to 27 m). Mass about 15 t. Hip height about 4.5 m. That is 14.7 human-lengths, or 2.23 of a double-decker bus. These are estimates from partial skeleton; fields marked estimated by the site are length, mass, hip height.

Compare Galeamopus with a bus Place on the timeline