| Summary: | A recently discovered small maniraptoran from the Morrison Formation of Wyoming provides new evidence for the placement or small Jurassic maniraptorans in theropod phylogeny. The specimen, WDC DML-01, is one of the oldest known taxa to be referred to the Troodontidae, estimated to be about 70% complete, and is assignable to the Order Maniraptora based on the presence of elongate forelimbs and manus almost as long as the pes. Previously, the earliest non-avian maniraptorans were Early Cretaceous in age with a gap of more than 20 million years between them and the Late Jurassic avian Archaeopteryx. WDC DML-01 provides a bridge in this stratigraphic gap in knowledge of maniraptoran evolution. WDC DML-01 also sheds light on the pattern of maniraptoran evolution, the adaptive grade of Jurassic deinonychosaurs, and possibly provides our earliest glimpse of an ecologic niche likely filled by small Jurassic maniraptorans.
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