Silesauridae
Encyclopedia
Silesauridae is an extinct clade
of dinosauriformes
, a group of Triassic
reptiles that included early ancestors of the dinosaur
s. The silesaurids were a sister clade to the dinosaurs. The family was named in 2010 by paleontologist Max C. Langer and colleagues from Brazil and Argentina. They defined it as a branch-based clade of all archosaurs closer to Silesaurus opolensis than to either Heterodontosaurus tucki or Marasuchus lilloensis. At the same time, a second group of scientists independently named Silesauridae as a node-based clade consisting of Lewisuchus
, Silesaurus, their common ancestor and all its descendants. Currently, both definitions encompass the same group of animals.
The fossils range in age from the Anisian to the Norian stages of the Triassic, about 245 to 203 million years ago.
Basal dinosauriform phylogeny simplified after Nesbitt
et al., 2011.
Among the members of the Silesauridae were Silesaurus
(which lends its name to the family), Pseudolagosuchus
, Lewisuchus
, Asilisaurus
, Technosaurus
, Eucoelophysis
, Sacisaurus
, and Diodorus
. The cladogram to the right shows one of two current (2010) phylogenies
of the Silesauridae.
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
of dinosauriformes
Dinosauriformes
Dinosauriformes is a clade of archosaurian reptiles that include the dinosaurs and their most immediate relatives. All dinosauriformes are distinguished by several features, such as shortened forelimbs, and an at least partially perforated acetabulum, the hole in the hip socket traditionally used...
, a group of Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
reptiles that included early ancestors of the dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
s. The silesaurids were a sister clade to the dinosaurs. The family was named in 2010 by paleontologist Max C. Langer and colleagues from Brazil and Argentina. They defined it as a branch-based clade of all archosaurs closer to Silesaurus opolensis than to either Heterodontosaurus tucki or Marasuchus lilloensis. At the same time, a second group of scientists independently named Silesauridae as a node-based clade consisting of Lewisuchus
Lewisuchus
Lewisuchus is a genus of archosaur that lived during the Middle Triassic ; it was a silesaurid dinosauriform, a member of the group of reptiles which lead to the dinosaurs. Lewisuchus was about three feet long. Fossils have been found in Argentina...
, Silesaurus, their common ancestor and all its descendants. Currently, both definitions encompass the same group of animals.
The fossils range in age from the Anisian to the Norian stages of the Triassic, about 245 to 203 million years ago.
Sterling Nesbitt
Sterling Nesbitt , is an American paleontologist.-Biography:Sterling Nesbitt received his B.A. in integrative biology with a minor in geology from University of California Berkeley in 2004. He received his Ph.D from Columbia University in 2009, completing the majority of his research at the...
et al., 2011.
Among the members of the Silesauridae were Silesaurus
Silesaurus
Silesaurus is a genus of dinosauriform from the Late Triassic, approximately 230 million years ago in the Carnian faunal stage of what is now Poland....
(which lends its name to the family), Pseudolagosuchus
Pseudolagosuchus
Pseudolagosuchus is a genus of dinosauromorph from the Middle Triassic Chañares Formation of Argentina. It may be a junior synonym of Lewisuchus, but there is very little overlapping material...
, Lewisuchus
Lewisuchus
Lewisuchus is a genus of archosaur that lived during the Middle Triassic ; it was a silesaurid dinosauriform, a member of the group of reptiles which lead to the dinosaurs. Lewisuchus was about three feet long. Fossils have been found in Argentina...
, Asilisaurus
Asilisaurus
Asilisaurus , and Greek, σαυρος is an extinct genus of silesaurid archosaur. It is the oldest avian-line archosaur, dating to about 245 million years ago....
, Technosaurus
Technosaurus
Technosaurus is an extinct genus of Late Triassic archosauriform, perhaps a dinosauriform similar to Silesaurus, from the Norian age Upper Triassic Bull Canyon Formation of Texas...
, Eucoelophysis
Eucoelophysis
Eucoelophysis is a genus of dinosauriform from the Late Triassic period Chinle Formation of New Mexico...
, Sacisaurus
Sacisaurus
Sacisaurus is a dinosauriform from the Late Triassic Caturrita Formation of southern Brazil...
, and Diodorus
Diodorus (genus)
Diodorus is a genus of silesaurid dinosauriform from the The Late Triassic Timezgadiouine Formation of the Argana Basin of Morocco...
. The cladogram to the right shows one of two current (2010) phylogenies
Phylogenetics
In biology, phylogenetics is the study of evolutionary relatedness among groups of organisms , which is discovered through molecular sequencing data and morphological data matrices...
of the Silesauridae.
External links
- Silesauridae in the Paleobiology Database