Lagerpetonidae
Encyclopedia
The Lagerpetonidae is a family
of basal
dinosauromorphs
. Members of the family are known from the Late Triassic
of Argentina
, Arizona
, New Mexico
, and Texas
.
oriented vertebrae, a sacral including two vertebrae, a closed acetabulum
, and an up facing ilium
". They had a short and wide pubis, and had an ischium with extensive ventral lamina. In relation to the genus
Lagosuchus
, the genera had shorter thigh bones
than shins
.
The lagerpetonids were relatives of the dinosaur
s, being a branch of the group Dinosauromorpha
. They were assigned by S. J. Nesbitt et al. 2009.
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
of basal
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...
dinosauromorphs
Dinosauromorpha
Dinosauromorpha is the name of a clade of archosaurs that includes the closest relatives of dinosaurs, and the order Dinosauria itself. Basal forms include Saltopus, Marasuchus, the perhaps identical Lagosuchus, the lagerpetonids Lagerpeton from the Ladinian of Argentina and Dromomeron from the...
. Members of the family are known from the Late Triassic
Late Triassic
The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...
of Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
, Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
, New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
, and Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
.
Description
Lagerpetonids are defined as being rather small (length of one hind limb being 25 centimetres (9.8 in)), with "very marked locomotor specializations", final presacral and anteriorlyAnatomical terms of location
Standard anatomical terms of location are designations employed in science that deal with the anatomy of animals to avoid ambiguities that might otherwise arise. They are not language-specific, and thus require no translation...
oriented vertebrae, a sacral including two vertebrae, a closed acetabulum
Acetabulum
The acetabulum is a concave surface of the pelvis. The head of the femur meets with the pelvis at the acetabulum, forming the hip joint.-Structure:...
, and an up facing ilium
Ilium (bone)
The ilium is the uppermost and largest bone of the pelvis, and appears in most vertebrates including mammals and birds, but not bony fish. All reptiles have an ilium except snakes, although some snake species have a tiny bone which is considered to be an ilium.The name comes from the Latin ,...
". They had a short and wide pubis, and had an ischium with extensive ventral lamina. In relation to the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Lagosuchus
Lagosuchus
Lagosuchus is a genus of small archosaur from the middle Triassic period. It is generally thought to be closely related to dinosaurs, as a member of the Dinosauromorpha...
, the genera had shorter thigh bones
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
than shins
Tibia
The tibia , shinbone, or shankbone is the larger and stronger of the two bones in the leg below the knee in vertebrates , and connects the knee with the ankle bones....
.
Classification and systematics
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, being a branch of the group Dinosauromorpha
Dinosauromorpha
Dinosauromorpha is the name of a clade of archosaurs that includes the closest relatives of dinosaurs, and the order Dinosauria itself. Basal forms include Saltopus, Marasuchus, the perhaps identical Lagosuchus, the lagerpetonids Lagerpeton from the Ladinian of Argentina and Dromomeron from the...
. They were assigned by S. J. Nesbitt et al. 2009.