Some long bony tailed pterosaurs (eg rhamphorhynchids) developed into long bony tailed scansoriopterygids. And some of those long bony tailed scansoriopterygids developed into other more derived long bony tailed members of Paraves. Then they went extinct.
But there are two paths. One from long bony tailed pterosaurs and the other from (later) short bony tailed pterosaurs (eg pterodactylids)
Some short bony tailed pterosaurs (eg pterodactylids) developed into short bony tailed scansoriopterygids. And some of the short bony tailed scansoriopterygids developed into pygostylia.
This means that later stage feathers (after stage IIIa) developed in both lines.
This suggests there was greater experimentation with wing-assisted locomotion before theropod flight evolved than previously appreciated. This study adds invaluable support for multiple origins of powered flight potential in theropods (≥3 times), which we now know was from ancestors already nearing associated thresholds, and provides a framework for its further study
In 1997, a node-based clade called Eumaniraptora ("true maniraptorans") was named by Padian, Hutchinson and Holtz. They defined their clade to include only avialans and deinonychosaurs. Paraves and Eumaniraptora are generally considered to be synonyms, though a few phylogenetic studies suggest that the two groups have a similar but not identical content; Agnolín and Novas (2011) recovered scansoriopterygids and alvarezsaurids as paravians that were not eumaniraptorans,[22] while Turner, Makovicky and Norell (2012) recovered Epidexipteryx as the only known non-eumaniraptoran paravian.[1] A nearly identical definition, "the theropod group that includes all taxa closer to Passer than to Dromaeosaurus", was used by Agnolín and Novas (2013) for their clade Averaptora.[23]
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