[D] Sacisaurus agudoensis [ncG]
Describer
Ferigolo & Langer, 2006
Time
Triassic Late Norian
Classification
Not considered dinosaur
Fossilsite
Caturrita Formation, Brazil
Info
Based on te remains of several individuals.
Eymology
Saci (Brazilian folklore), a famous one-legged elf from brazilian mythology, due to the fact that the fossil skeleton has been found missing a leg and to the city where the sacisaur was found, Agudo in the Rio Grande do Sul state.
Abstract
The South American Late Triassic offers the most comprehensive window to the early radiation of dinosaurs. This is enhanced by the discovery of Sacisaurus agudoensis, a new dinosauriform from the Caturrita Formation of Brazil.
Various morphological features suggest its close phylogenetic affinity to Silesaurus, and both may be basal ornithischian dinosaurs. Sacisaurus has a pair of elements forming the tip of its lower jaw, hypothesized to be equivalent to the ornithischian predentary. This suggests that during an initial stage of their evolution, those dinosaurs had a paired predentary, whichlater fused into a single structure.
As an originally paired bone, the predentary is comparable to elements that more often form the vertebrate mandible, such as the mentomeckelian bone. Although synapomorphic for ornithischians, the predentary does not seem neomorphic for the group, but primarily homologous to parts of the symphyseal region of the lower jaw of other vertebrates.
Ferigolo & Langer, 2006
Time
Triassic Late Norian
Classification
Not considered dinosaur
Fossilsite
Caturrita Formation, Brazil
Info
Based on te remains of several individuals.
Eymology
Saci (Brazilian folklore), a famous one-legged elf from brazilian mythology, due to the fact that the fossil skeleton has been found missing a leg and to the city where the sacisaur was found, Agudo in the Rio Grande do Sul state.
Abstract
The South American Late Triassic offers the most comprehensive window to the early radiation of dinosaurs. This is enhanced by the discovery of Sacisaurus agudoensis, a new dinosauriform from the Caturrita Formation of Brazil.
Various morphological features suggest its close phylogenetic affinity to Silesaurus, and both may be basal ornithischian dinosaurs. Sacisaurus has a pair of elements forming the tip of its lower jaw, hypothesized to be equivalent to the ornithischian predentary. This suggests that during an initial stage of their evolution, those dinosaurs had a paired predentary, whichlater fused into a single structure.
As an originally paired bone, the predentary is comparable to elements that more often form the vertebrate mandible, such as the mentomeckelian bone. Although synapomorphic for ornithischians, the predentary does not seem neomorphic for the group, but primarily homologous to parts of the symphyseal region of the lower jaw of other vertebrates.