Fossils of a new dinosaur species discovered in Morocco are shedding light on the evolutionary relationships between dinosaurs and other animals, and providing clues as to why they went extinct.

The new species, named _Adynomosaurus arcanus_ (“mysterious undiscovered reptile”), was a small, bird-like dinosaur that lived in North Africa about 66 million years ago, during the Late Cretaceous period. It was discovered in the Kem Kem Group, a geological formation in Morocco that has yielded a wealth of dinosaur fossils.

_Adynomosaurus_ was a member of the group of dinosaurs known as theropods, which includes the fearsome _Tyrannosaurus rex_ as well as modern-day birds. However, _Adynomosaurus_ was much smaller than _T. rex_, weighing only about 10 kilograms (22 pounds). It had long legs, a slender body, and a long, bony tail.

_Adynomosaurus_ is significant because it helps to fill in a gap in the fossil record of theropods. It is one of the most complete skeletons of a small theropod from the Late Cretaceous period, and it provides new information about the evolution of feathers, flight, and bird origins.

The discovery of _Adynomosaurus_ also provides clues about the extinction of the dinosaurs. The Kem Kem Group, where _Adynomosaurus_ was found, was once a lush, tropical environment, but it became increasingly dry and arid during the Late Cretaceous period. This change in climate may have contributed to the extinction of many dinosaur species, including _Adynomosaurus_.

The discovery of _Adynomosaurus_ is an important addition to our knowledge of the dinosaurs. It provides new insights into the evolution of dinosaurs, and it helps us to better understand the causes of their extinction.