"J. David Archibald's Bird Lizard"
Brett-Surman & Paul, 1985
Length: 45cm (1.5ft)
Weight: 200g (7oz)
Location: Montana, USA
Era: Maastrichtian age, upper Cretaceous (65 million years ago)
The youngest known Enantiornithine, Avisaurus represents a problem many Enantiornithine birds have, known from very scant fossils--in the case with Avisaurus, only a single tarsometatarsus has been published (though there is apparently an undescribed partial skeleton).