Aniksosaurus is an extinct dinosaur that lived in what we now call Argentina during the Late Cretaceous period, about 96 to 91 million years ago. The name Aniksosaurus means “spring lizard.” It was named because its fossils were found in the spring, specifically on September 21, 1995.
The dinosaur was described in 2006 based on fossils found in an area known as the Bajo Barreal Formation. The full name of this species is Aniksosaurus darwini, named in honor of Charles Darwin, who visited Patagonia a long time ago.
### Description
The main fossils of Aniksosaurus include its right leg bones, which were discovered together. The longest thigh bone, called the femur, was around 24.7 centimeters long, and the shin bone, or tibia, was about 27 centimeters long.
Initially, scientists thought Aniksosaurus was about 2 meters long and 70 centimeters tall at the hip. But newer estimates suggest it could reach lengths of 2 to 3 meters and weigh between 35 to 65 kilograms.
Studies of Aniksosaurus show that it likely did not live long enough to reach full adulthood when the fossils were found. This was determined by looking closely at the bones and noticing characteristics of younger individuals.
### Classification
Aniksosaurus belongs to a group of dinosaurs known as theropods, which are mostly known for being carnivorous. It is considered to be linked to other small theropods, but its exact place in the dinosaur family tree is still being studied.
Some unique features help scientists identify Aniksosaurus. For example, it had special bone shapes in its neck and back, which were adapted for movement. Its leg bones had certain qualities that indicated it was likely fast and agile.
### Behavior
There is evidence suggesting that Aniksosaurus may have been social, living in groups during certain times of its life. This idea comes from finding multiple bones in one location. Being in groups may have helped them survive better and fend off predators.
### Where It Lived
The fossils of Aniksosaurus were found in the lower Bajo Barreal Formation, which was a floodplain environment during its time. Many other dinosaur fossils are also found in this area, showing a rich variety of life. Examples include other large dinosaurs like sauropods and carnivorous dinosaurs.
The area where Aniksosaurus lived had a specific type of environment that was gentle and provided conditions suitable for various life forms. Fossils show that the remains were well-preserved and suggest that Aniksosaurus lived a life typical of small, agile dinosaurs of that time.
In summary, Aniksosaurus is a fascinating dinosaur from millions of years ago, and studying it gives us insights into life during the Late Cretaceous period in what is now Argentina.