Leptorhynchos

Leptorhynchos was a small caenagnathid theropod from the Late Cretaceous of North America, described from the Aguja Formation in western Texas. Measuring roughly one to one and a half metres long, it was considerably smaller than contemporary giants like Anzu. The genus is distinguished by its delicate, upturned lower jaw with a distinctly pointed tip and specialized vascular grooves, pointing to an animal equipped with a sharp keratinous rhamphotheca. Because it lived in coastal plain environments, it may have fed on small vertebrates, invertebrates, and soft waterside vegetation. Although known from limited skeletal elements, its presence reveals that caenagnathids occupied diverse ecological niches across North America.

A diminutive caenagnathid recognized primarily from delicate, upturned lower jawbones.

Where and when

Leptorhynchos lived in the Late Cretaceous, from 80.5 to 75 million years ago (Campanian age). Its remains come from United States, in the Aguja Formation.

The numbers

Length 1.4 m (estimates run from 1.2 to 1.5 m). Mass about 16 kg. Hip height about 0.6 m. That is 0.8 human-lengths, or 0.13 of a double-decker bus. These are estimates from fragmentary remains; fields marked estimated by the site are length, mass, first ma, last ma, hip height.

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