Pisanosaurus

Pisanosaurus skull

PisanosaurusROM1

Pisanosaurus

Pisanosaurus NT small

Pisanosaurus is a genus of early dinosaur from the Late Triassic period. It is known from a single species, Pisanosaurus mertii, which was discovered in the Ischigualasto Formation of northwestern Argentina. This genus is significant as it is considered one of the earliest known ornithischian dinosaurs.

Discovery and Naming

The fossil remains of Pisanosaurus were discovered in 1967 by the Argentine paleontologist Rodolfo Casamiquela. The genus name Pisanosaurus honors the Argentine paleontologist Juan Arnaldo Pisano, while the species name mertii is in honor of the geologist Osvaldo Merti.

Description

Pisanosaurus is known from a partial skeleton, which includes parts of the skull, vertebrae, and limbs. It was a small, bipedal herbivore, estimated to be about 1 meter (3.3 feet) in length. The structure of its teeth and jaws suggests it was adapted to a herbivorous diet, typical of early ornithischians.

Classification

Pisanosaurus is classified within the clade Ornithischia, which is one of the two major groups of dinosaurs, the other being Saurischia. Ornithischians are characterized by their bird-like pelvic structure. The exact phylogenetic position of Pisanosaurus within Ornithischia is still debated, but it is generally considered to be one of the most basal members of this group.

Paleoecology

The Ischigualasto Formation, where Pisanosaurus was found, dates to the Late Triassic period, approximately 228 to 216 million years ago. This formation is known for its diverse assemblage of early dinosaurs and other prehistoric life, including theropods, sauropodomorphs, and various synapsids and archosaurs. The environment of the Ischigualasto Formation was likely a humid, warm climate with seasonal rainfall, supporting a variety of plant life that Pisanosaurus would have fed on.

Significance

The discovery of Pisanosaurus provides important insights into the early evolution of ornithischian dinosaurs. As one of the earliest known members of this group, it helps paleontologists understand the early diversification and adaptations of herbivorous dinosaurs.

Related Pages

• Ornithischia
• Ischigualasto Formation
• Triassic
• Rodolfo Casamiquela
• Juan Arnaldo Pisano