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Avisaurids
Avisauridae is a Family (biology), family of Extinction, extinct Enantiornithes, enantiornithine dinosaurs from the Cretaceous period, distinguished by several features of their ankle bones. Depending on the definition used, Avisauridae is either a broad and widespread group of advanced enantiornithines (following Cau & Arduini, 2008), or a small family within that group, restricted to species from the Late Cretaceous of North and South America (following Chiappe, 1992). Description Avisaurids were among the largest and last enantiornithines to have lived, although they are also among the most poorly preserved. The majority of them are known primarily from fossilized Tarsometatarsus, tarsometatarsal bones, the part of a bird's leg formed by fused Metatarsal bones, metatarsals (the bones which comprise the foot in humans). As a result, members of this family are distinguished from other enantiornithines exclusively by features of the tarsometatarsal and pedal Phalanx bone, phalan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enantiornithes
The Enantiornithes, also known as enantiornithines or enantiornitheans in literature, are a group of extinct Avialae, avialans ("birds" in the broad sense), the most abundant and diverse group known from the Mesozoic era. Almost all retained teeth and clawed fingers on each wing, but otherwise looked much like modern birds externally. Over seventy species of Enantiornithes have been named, but some names represent only single bones, so it is likely that not all are valid. The Enantiornithes became extinct at the Cretaceous–Paleogene boundary, along with Hesperornithes and all other non-avian dinosaurs. Discovery and naming The first Enantiornithes to be discovered were incorrectly referred to modern bird groups. For example, the first known species of Enantiornithes, ''Gobipteryx minuta'', was originally considered a paleognath related to ostriches and tinamou. The Enantiornithes were first recognized as a distinct lineage, or "subclass" of birds, by Cyril A. Walker in 1981. W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
