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Leptoceratopsid maxilla from Late Cretaceous of eastern North America

Ben Creisler

A new paper:

Nicholas R. Longrich (2016) [2015]
A ceratopsian dinosaur from the Late Cretaceous of eastern North
America, and implications for dinosaur biogeography.
Cretaceous Research 57: 199–207

Tyrannosaurs and hadrosaurs from the Late Cretaceous of eastern North
America (Appalachia) are distinct from those found in western North
America (Laramidia), suggesting that eastern North America was
isolated during the Late Cretaceous. However, the Late Cretaceous
fauna of Appalachia remains poorly known. Here, a partial maxilla from
the Campanian Tar Heel Formation (Black Creek Group) of North Carolina
is shown to represent the first ceratopsian from the Late Cretaceous
of eastern North America. The specimen has short alveolar slots, a
ventrally projected toothrow, a long dentigerous process overlapped by
the ectopterygoid, and a toothrow that curves laterally, a combination
of characters unique to the Leptoceratopsidae. The maxilla has a
uniquely long, slender and downcurved posterior dentigerous process,
suggesting a specialized feeding strategy. The presence of a highly
specialized ceratopsian in eastern North America supports the
hypothesis that Appalachia underwent an extended period of isolation
during the Late Cretaceous, leading the evolution of a distinct
dinosaur fauna dominated by basal tyrannosauroids, basal hadrosaurs,
ornithimimosaurs, nodosaurs, and leptoceratopsids. Appalachian
vertebrate communities are most similar to those of Laramidia. However
some taxa-including leptoceratopsids-are also shared with western
Europe, raising the possibility of a Late Cretaceous dispersal route
connecting Appalachia and Europe.