What is the closest thing to dinosaurs

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Closest Relatives to Dinosaurs: Insights from Recent Research

Dromaeosaurids: Feathered Relatives of Birds

Dromaeosaurids, often referred to as "raptors," are among the closest relatives to modern birds. These theropod dinosaurs from the Early Cretaceous period exhibit significant similarities to birds, particularly in their feather structures. The discovery of Zhenyuanlong suni, a large-bodied, short-armed dromaeosaurid from Liaoning Province, China, has provided crucial insights into feather evolution. This species had large wings with pennaceous feathers on the arms and tail, similar to smaller dromaeosaurids, but likely lacked vaned feathers on the legs. These findings highlight the diversity within dromaeosaurids and their close evolutionary relationship with birds.

Dinosauriforms: Precursors to Dinosaurs

Dinosauriforms, such as Asilisaurus kongwe, are another group closely related to dinosaurs. Asilisaurus, from the Middle Triassic period of Tanzania, provides a detailed anatomical record that helps clarify the evolutionary relationships of early dinosaurs. This species had a unique combination of features, including a crocodylian-like ankle and a short foot with well-developed metatarsals, which are plesiomorphic traits for Archosauria. The detailed study of Asilisaurus suggests high homoplasy and parallel evolutionary trends within early dinosaur lineages and their relatives. This indicates that dinosauriforms like Asilisaurus are crucial for understanding the early evolutionary stages leading to true dinosaurs.

Silesaurids: Non-Dinosaurian Dinosauriforms

Silesaurids, such as Sacisaurus agudoensis from the Late Triassic period of Brazil, are considered the closest non-dinosaurian relatives of crown-group dinosaurs. The osteohistology of Sacisaurus reveals rapid growth patterns similar to early dinosaurs, although they lack the complex vascular arrangements seen in saurischian dinosaurs. Instead, silesaurids exhibit simpler vascular patterns, indicating relatively slower growth rates. This simpler bone structure is consistent across all studied silesaurids and provides important clues about the growth and development of early dinosauromorphs. These findings underscore the significance of silesaurids in understanding the origins and early evolution of dinosaurs.

Conclusion

The closest relatives to dinosaurs include dromaeosaurids, dinosauriforms, and silesaurids. Dromaeosaurids, with their bird-like feathers, highlight the evolutionary link between dinosaurs and birds. Dinosauriforms like Asilisaurus provide critical anatomical details that help unravel the complex evolutionary history of early dinosaurs. Silesaurids, as the nearest non-dinosaurian relatives, offer valuable insights into the growth and development patterns that preceded true dinosaurs. Together, these groups paint a comprehensive picture of the evolutionary landscape surrounding the origin of dinosaurs.