First parrot-sized dino with only one finger discovered in China
By ANITuesday, January 25, 2011
WASHINGTON - Scientists have discovered a new species of parrot-sized dinosaur that has only one finger, in China.
It belongs to the Alvarezsauroidea, a branch of the carnivorous dinosaur group Theropods - which eventually evolved into Tyrannosaurus and Velociraptor.
The well-preserved fossil was uncovered in rocks of the Upper Cretaceous Wulansuhai Formation, which is located near the border between Mongolia and China and is about 84-75 million years old.
Named Linhenykus monodactylus, it most likely grew to a couple of feet tall and weighed only as much as a large parrot.
The single claw may have been used to dig into insect nests, on each of its hands.
“Non-avian theropods start with five fingers but evolved to have only three fingers in later forms.
Tyrannosaurs were unusual in having just two fingers but the one-fingered Linhenykus shows how extensive and complex theropod hand modifications really were,” said Michael Pittman of the Department of Earth Sciences at University College London.
“Linhenykus highlights the vestigiality of the outer fingers of advanced alvarezsauroids and underscores the complexity in evolution of these vestigial fingers,” noted Jonah Choiniere at the American Museum of Natural History.
Although Linhenykus co-existed with closely-related and similarly-sized theropods, the specializations of its skeleton may reflect differences in behaviour or foraging strategy.
They also lived alongside small mammals, lizards, clubbed dinosaurs (ankylosaurs) and horned dinosaurs (ceratopsians).
The find appears in Proceedings of the National Academy of Sciences (PNAS).(ANI)
