Published today in Communications Biology, Imai et al. have unveiled a new basal bird from central Japan they have named
Fukuipteryx prima or ‘Fukui’s primitive wing’. This little Early
Cretaceous bird is only the size of a pigeon, roughly, but it has some
features that really set it apart from the other basal birds that we
have found so far: it is an fairly entire skeleton preserved
three-dimensionally, and it has a pygostyle!
(Adapted from Fig 1 in Imai et al. 2019)
A pygostyle is the shortened, fused tail vertebrae, which is seen in all modern birds but is difficult to place in more basal birds. Pygostyles are hypothesized to be critical to the evolution of powered flight, so it is interesting to find it on a bird with other more basal traits. Note that this team placed Fukuipteryx as more basal than Jeholornis, which has a distinctly fan-tipped long tail, suggesting that the pygostyle may have evolved multiple times, and might mean we need to rethink a linear progression in the development of powered flight in birds.
The full article is available to read here in Communications Biology. If anyone cannot access it, please message me and I will happily share a PDF copy.
