Lithornis is a genus of extinct paleognathous birds. Although Lithornis was able to fly well, their closest relatives are the extant tinamous (which are poor flyers) and ratites (which are flightless birds).

The oldest raptorial bird (Lithornis) known is from the late Paleocene Epoch (57.9 to 54.8 million years ago) and may have been a New World vulture (family Cathartidae). Cathartids may have evolved in the Old World, dying out there and surviving only in the New World.

Lithornithidae is an extinct, possibly paraphyletic [1] (but see below) group of early paleognath birds.

Lithornis: genus: belongs to Ornithurae: stated with evidence: Kurochkin et al., 2013: Status (PBDB) extinct: Taxon Size (PBDB) 8: First Recorded Appearance: 61.7 - 56.8 Ma Paleocene: Last Recorded Appearance: 47.8 - 41.3 Ma Eocene: Environment: terrestrial (based on Theropoda) Motility:

Here, we report five new partial skeletons of lithornithids from the Fossil Butte Member of the Green River Formation (early Eocene) of Wyoming. One spectacularly preserved specimen is identified as the holotype of a new species, Calciavis grandei, gen. et …

Description of the fossil remains of a mammal (Hyracotherium leporinum) and of a bird (Lithornis vulturinus) from the London clay. Transactions of the Geological Society of London 6: 203–208. DOI : 10.1144/transgslb.6.1.203 BHL

Here, we report five new partial skeletons of lithornithids from the Fossil Butte Member of the Green River Formation (Early Eocene) of Wyoming. One spectacularly preserved specimen is identified as the holotype of a new species, Calciavis grandei, gen. et …

The flying ratite (Lithornis sciifii, name meaning "SciiFii's stone bird) is a species of paleognathous bird that originally lived in the early Cenozoic (and possibly the Cretaceous) in what is now North America and England as several extinct species and was once extinct, but has since been...

Jan 7, 2025 · We describe multiple partial skeletons and isolated bones of the palaeognathous Lithornithiformes from the early Eocene London Clay of Walton-on-the-Naze (Essex, UK). The well-preserved specimens are assigned to at least four species of the taxa Lithornis and Pseudocrypturus. Two species of Lithornis are identified as L. nasi and L. cf. grandei.

Lithornis may provide the clearest insights to date into the neuroanatomy of the ancestral crown bird, combining an ancestrally unflexed brain with a caudally oriented connection with the spinal cord, a moderately enlarged telencephalon, and ventrally shifted, enlarged optic lobes.