maniraptoran

Maniraptora is a clade of theropod dinosaurs within the larger group Coelurosauria that includes the birds and many of their closest non-avian relatives. Members are diverse, including dromaeosaurs (raptors), troodontids, oviraptorosaurs, and therizinosaurs. In most classifications, Maniraptora is defined by shared derived features that unite birds and these relatives; the exact boundaries vary among researchers. The group represents a key stage in the evolution of flight and bird-like physiology.

Characteristic traits include a more flexible wrist, often a semilunate carpal that allows rapid flexion of the hand, and elongated forelimbs. Feathering is widespread among maniraptorans, with evidence of pennaceous wing feathers and tail fans in several lineages. Many have reduced teeth or toothless beaks, and several lineages show adaptations for precise predation, omnivory, or herbivory. The skeletons typically reveal keen senses and enlarged brains compared with earlier theropods.

Among non-avian members, dromaeosaurids and troodontids were small to medium-sized predators with agile builds and specialized claws. Oviraptorosaurs and therizinosaurs have unusual skulls and feeding adaptations, including beaked snouts and herbivorous tendencies in therizinosaurs. Birds are the only surviving lineage, forming the crown group, with some lineages achieving powered flight and maintaining many maniraptoran traits in their skeletons and plumage.

Originating in the Jurassic, maniraptorans diversified during the Cretaceous across multiple landmasses. Birds emerged from within this clade by the Late Jurassic to Early Cretaceous, leaving a living lineage that directly descends from maniraptorans.