Every so often it’s worthwhile to take a wider view
to appreciate the model of evolution hypothesized by the large reptile tree (LRT, 1761+ taxa) to see the patterns of microevolution it documents. Otherwise, all you have is a long list of under-appreciated taxa on a dense family tree.
Today, let’s look at the ancestry of one of the smartest birds,
(Corvus brachyrhynchos, Linneaus 1758; Fig. 1), the extant American crow. Derived from a long list of longer-legged freshwater shorebirds, Corvus is generalized bird close to the stone curlew (Burhinus) and the grackle (Oedicnemus) and basal to robins, jays, birds of paradise and cuckoos.
The presence of Eogranivora in the Early Cretaceous indicates that sisters to Pseudocrypturus and Crypturus (close to Megapodius) are more ancient. Seriemas, storks and corn crakes are more recent, perhaps radiating in the Late Cretaceous. Short-legged taxa are neotonous, since chicks of long-legged taxa do not have such long bills and long legs as adults. This makes birds different than pterosaurs, in which hatchlings are identical to 8x larger adults.
Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.