lorenornithids

Lorenornithids were a group of extinct birds belonging to the order Hesperornithiformes. These ancient birds are known from fossils found in the late Cretaceous period, primarily in North America. Lorenornithids were characterized by their large size and a lack of functional wings, indicating they were flightless. Their skeletal features suggest they were adapted for a marine or semi-aquatic lifestyle, likely spending much of their time in the water.

The diet of lorenornithids is believed to have consisted of fish, which they would have caught in their aquatic environments. Their jaws were equipped with sharp teeth, or more accurately, serrated bony projections, which aided in grasping slippery prey. Unlike modern birds, lorenornithids retained teeth in their jaws, a primitive trait shared with other early birds and their reptilian ancestors.

The most distinctive feature of lorenornithids, and indeed all hesperornithiforms, is their highly specialized pelvic girdle. It was adapted to allow them to swim effectively, with their legs positioned far back on their bodies. This arrangement, similar to that seen in modern diving birds like grebes, would have provided powerful propulsion through the water. However, it also made them awkward on land, necessitating a largely aquatic existence. The exact evolutionary relationships and classification within the Hesperornithiformes are still subjects of scientific research.