Tytthostonyx is a genus of prehistoric seabird. Found in the much-debated Hornerstown Formation which straddles the Cretaceous-Paleocene boundary 65 million years ago, this animal was apparently closely related to the ancestor of some modern birds, such as Procellariiformes and/or Pelecaniformes. A single species is placed herein, Tytthostonyx glauconiticus. It has been placed into a family of its own, Tytthostonygidae, but whether this is appropriate can't be determined at present.… (More on Tytthostonyx)