Maniraptoriformes

Maniraptoriformes is a clade of coelurosaurian dinosaurs that includes both the non-avian dinosaurs and the birds (Aves). Originating in the Late Jurassic period, Maniraptoriformes is distinguished by various skeletal features, especially in the pelvis, hand, and shoulder. Members of this group are characterized by their three-fingered hands and a semi-lunate carpal (a crescent-shaped wrist bone), which are indicative of their evolutionary adaptations towards flight and improved manual dexterity.

Characteristics

Maniraptoriformes exhibit a range of distinctive features that set them apart from other dinosaurs. These include a more bird-like pelvis, in which the pubis bone points backward and down, a feature that is also seen in modern birds. Their forelimbs are elongated, with the presence of a semi-lunate carpal bone, allowing for a greater range of motion. This adaptation is crucial for the wing movements in avian species and also facilitated the varied feeding and hunting strategies of non-avian maniraptoriforms.

Evolution and Phylogeny

The evolutionary history of Maniraptoriformes is complex, with the group showing a high degree of diversification during the Cretaceous period. Phylogenetically, Maniraptoriformes is situated within Theropoda, a larger group of bipedal saurischian dinosaurs. Within Maniraptoriformes, several subgroups are recognized, including Deinonychosauria (which includes Velociraptor and its relatives), Therizinosauroidea, and Avialae, the clade that encompasses all modern birds and their closest dinosaurian relatives.

Fossil Record

The fossil record of Maniraptoriformes is rich, with specimens found across the world, from Asia to the Americas. These fossils have provided critical insights into the life appearance, behavior, and ecology of these animals. Notable fossil sites include the Yixian Formation in China, which has yielded well-preserved specimens of early birds and feathered dinosaurs, highlighting the evolutionary transition from non-avian dinosaurs to birds.

Classification

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Paleobiology

Maniraptoriformes displayed a wide array of lifestyles, from the carnivorous habits of Velociraptor to the herbivorous or omnivorous diets of some therizinosaurs and oviraptorosaurs. The presence of feathers in many maniraptoriforms, including non-avian species, suggests that these structures initially evolved for purposes other than flight, such as insulation, display, or brooding.

Impact on Science and Culture

The discovery and study of Maniraptoriformes have significantly impacted our understanding of dinosaur biology and the evolution of birds. These creatures have also captured the public imagination, featuring prominently in popular culture, notably in films, literature, and documentaries.

See Also

• Feathered dinosaur
• Origin of birds
• Dinosaur classification