Pisanosaurus

Pisanosaurus skull

PisanosaurusROM1

Pisanosaurus

Pisanosaurus NT small

Pisanosaurus is a genus of dinosaur that lived during the Late Triassic period, approximately 228 million years ago, in what is now South America. It is known from a single partial skeleton discovered in the Ischigualasto Formation in Argentina, making it one of the earliest known dinosaurs. The genus contains a single species, Pisanosaurus mertii, named in honor of Juan A. Merti, who was instrumental in its discovery.

Description

Pisanosaurus was a small, bipedal animal, estimated to have been about 1 meter (3.3 feet) in length and weighing approximately 2.5 kilograms (5.5 pounds). Its body structure suggests it was a fast runner. The dentition of Pisanosaurus indicates it was herbivorous, with teeth adapted for a plant-based diet. However, due to the incomplete nature of the fossil record, interpretations of its diet and lifestyle are based on limited evidence.

Discovery and Naming

The only known specimen of Pisanosaurus was discovered in 1962 by a team led by Argentine paleontologist Rodolfo Casamiquela. The genus name, Pisanosaurus, means "Pisano's lizard", in honor of Argentine paleontologist Juan A. Pisano, and the species name, mertii, honors Juan A. Merti. The fossil remains include parts of the skull, lower jaw, vertebrae, ribs, and limbs, but the skeleton is not complete.

Classification

The classification of Pisanosaurus has been a subject of debate among paleontologists. Initially, it was classified as a member of the Ornithischia, a major group of herbivorous dinosaurs that includes stegosaurs, ankylosaurs, and the horned dinosaurs. However, some studies have suggested that Pisanosaurus might not be a true ornithischian but rather a basal member of the dinosaur lineage, close to the split between ornithischians and saurischians, which includes all carnivorous dinosaurs and the group that would evolve into birds. The precise placement of Pisanosaurus within the dinosaur family tree remains uncertain due to the paucity of its remains.

Significance

The discovery of Pisanosaurus is significant because it represents one of the earliest known dinosaurs, providing valuable insights into the early evolution and diversification of dinosaurs. Its placement within the dinosaur family tree can help paleontologists understand more about the origins and early evolutionary history of dinosaurs.

See Also

• Dinosaur
• Triassic
• Ornithischia
• Saurischia
• Ischigualasto Formation