Owls Flew Over Dinosaurs

Fossil leg bones from
Montana dinosaur beds
look like those of raptors

Newly discovered Late Cretaceous birds may have carried heavy prey like extant raptors (9 Oct 2024, PLoS via Science Daily). The old story of “primitive” birds during the age of dinosaurs has taken another blow. Leg bones found in dinosaur beds in Montana look like raptor legs, most specifically like those of owls.

Analysis of the leg bones of Avisaurus and its relatives reveals proportions and adaptations similar to hawks and owls, indicating powerful leg muscles and feet that could grip and potentially carry proportionally large prey, similar to some modern raptorial birds.

New enantiornithine diversity in the Hell Creek Formation and the functional morphology of the avisaurid tarsometatarsus (Clark et al, PLoS One, 9 Oct 2024). This is the paper announcing the details of the find.

The morphology and topography of the tarsometatarsus greatly varies among extant birds, and can signal certain ecological behaviors such as wading, cursoriality, perching, prey grasping abilities, and pedal digit to substrate interaction [45–51]. When assessing the length and width of the tarsometatarsus of Mesozoic taxa, avisaurids overlap with a range of terrestrial nonvolant theropods (Fig 7 and S4 Table). Thus, it is not surprising avisaurids were originally interpreted as non-avian, or as having reduced flight capabilities [12]. However, when modern birds are added to the dataset, avisaurids cluster with larger birds like pelicans, owls, and hornbills weakening support for using the aspect ratio of the tarsometatarsus alone to predict volancy (Fig 7).

The paper finds many similarities to the leg bones of extant birds of prey. The authors have little to say about evolution. Incidentally, the Hell Creek Formation where these bones were found also contained dinosaur bones with soft tissue intact.

The evidence seems too scanty to assign these bones to “enantiornithines” (supposedly primitive birds that went extinct before modern birds “evolved”), let alone dividing the bones into three species. Why not just admit that these are bones from modern raptors? Nothing except the evolutionary timeline (i.e., the notion that modern birds should not have evolved that early) seems to require assigning these to enantiornithines. Darwin skeptics may want to follow up on this new evidence.

The Hell Creek formation also includes sea shells and marine fossils. It looks like a mass of different animals were all buried together in a Flood not that long ago.