BIOGEOGRAPHIC AND BIOSTRATIGRAPHIC SIGNIFICANCE OF THE NAVESINK/HORNERSTOWN AND LANCE/HELL CREEK AVIFAUNAS

The Hornerstown and Navesink Formations of New Jersey and the Lance and Hell Creek Formations of the Western Interior are close in age and have similar avifaunules. We compare these faunules and discuss their significance for bird survival at the end of the Cretaceous. The eastern and western depositional environments were respectively offshore shallow marine, and terrestrial freshwater in the region of an epicontinental seaway. In both regions Neornithes (modern birds) are numerically dominant, and most have shorebird or seabird features. Western sites include non-neornithine birds as a small component. The Hornerstown birds include one specimen provisionally identified as a lithornid from the terrestrial group Palaeognathae; this would be the earliest fossil evidence of that group. Both regions have specimens from the major extant group Anseriformes (which includes ducks and geese). Western sites include a possible stem-group galliform Palintropus. Wing morphology of the two Graculavus species present respectively in eastern and western sites indicates powerful flight. Fragmentary specimens of presbyornithid anseriforms were present in the western sites. Presbyornithids also appear to have had strong flight, judging by more complete specimens from other sites. Powerful flight and cosmopolitan distributions with associated refuge areas may have played a major role in survival and recovery of neornithine birds through the end-Cretaceous events.