Birds are synonymous with beaks of various shapes and sizes but new fossils unearthed by researchers show that their ancestors had even evolved teeth for specialised diets, according to a US study. For instance, Sulcavis geeorum, an enantiornithine bird from the Early Cretaceous (121-125 million years ago) of Liaoning province in China, had a durophagous diet, meaning that its teeth were capable of eating prey with hard outer skeletons like insects or crabs.
Enantiornithine birds are an early group of birds, and the most numerous birds from the Mesozoic (the time of the dinosaurs). Sulcavis is the first discovery of a bird with ornamented tooth enamel, the Journal of Vertebrate Paleontology reports.
Researchers from the Natural History Museum of Los Angeles county believe the teeth of the new specimen greatly increase the known diversity of tooth shape in early birds, and hints at previously unrecognized ecological diversity.
The dinosaurs - from which birds evolved - are mostly characterised by carnivorous teeth with special features for eating meat. The enantiornithines are unique among birds in showing minimal tooth reduction and a diversity of dental patterns, according to a Natural History statement.
This new enantiornithine has robust teeth with grooves on the inside surface, which likely strengthened the teeth against harder food items, says Luis Chiappe, from Natural History Museum, who co-authored the study.
"While other birds were losing their teeth, enantiornithines were evolving new morphologies and dental specialisations. We still don't understand why enantiornithines were so successful in the Cretaceous but then died out - maybe differences in diet played a part," says Jingmai O'Connor, who led the study.