Pampadromaeus
Encyclopedia
Pampadromaeus is an extinct genus
of basal
sauropodomorph dinosaur
s known from the Triassic
of Rio Grande do Sul
, southern Brazil.
specimen ULBRA
-PVT016, a disarticulated, partial but well preserved skeleton
from a single individual which includes most of the skull
bones and the lower jaws; dorsal, sacral and caudal vertebrae; elements of the shoulder girdle
and the forelimb
s, an ilium
and elements of the hindlimbs. It was collected in the upper Hyperodapedon
biozone from the Alemoa Member of the Santa Maria Formation
(Rosário do Sul Group) in the "Janner" (also known as "Várzea do Agudo") locality, geopark
of Paleorrota
, dating to the Carnian
faunal stage
of the early Late Triassic
, about 230-228 million years ago.
, the Theropoda
: the premaxilla
is pointed downwards forming a subnarial gap with the maxilla
and the anterior-most teeth are unserrated; in the location where with theropods the fenestra promaxillaris is positioned, a small depression is present. Basal traits consist of a large skull, a short thighbone, the possession of just two sacral vertebrae and the presence of fifteen teeth in the pterygoid
.
There were four teeth in the premaxilla and about twenty in both the maxilla and the lower jaw for a total of eighty-eight. The teeth were large, elongated, lanceolate, slightly recurved, sharply pointed and coarsely serrated. The lower leg was much longer than the thighbone, indicating Pampadromaeus was good runner.
and the type species
is Pampadromaeus barberenai. The generic name is derived from Quechua
pampa, "plain", in reference to the present landscape of the site, and Greek δρομεύς, dromeus, "runner", referring to the cursorial habits; the Latinised spelling variant dromaeus is used. The specific name honours the Brazilian paleontologist Mário Costa Barberena
.
sauropodomorph in four different cladistic analyses. The describers emphasized however, that this position was not strongly supported, showing the difficulties of determining the affinities of such early forms with the basal Dinosauromorpha
, Saurischia
, Sauropodomorpha and Theropoda.
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...
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:...
sauropodomorph 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 known from the 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...
of Rio Grande do Sul
Rio Grande do Sul
Rio Grande do Sul is the southernmost state in Brazil, and the state with the fifth highest Human Development Index in the country. In this state is located the southernmost city in the country, Chuí, on the border with Uruguay. In the region of Bento Gonçalves and Caxias do Sul, the largest wine...
, southern Brazil.
Discovery
Pampadromaeus is known only from the holotypeHolotype
A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...
specimen ULBRA
Museu de Ciências Naturais da Fundação Zoobotânica do Rio Grande do Sul
The Museu de Ciências Naturais da Fundação Zoobotânica do Rio Grande do Sul , is a Brazilian museum located inside the Porto Alegre Botanical Garden...
-PVT016, a disarticulated, partial but well preserved skeleton
Skeleton
The skeleton is the body part that forms the supporting structure of an organism. There are two different skeletal types: the exoskeleton, which is the stable outer shell of an organism, and the endoskeleton, which forms the support structure inside the body.In a figurative sense, skeleton can...
from a single individual which includes most of the skull
Skull
The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...
bones and the lower jaws; dorsal, sacral and caudal vertebrae; elements of the shoulder girdle
Girdle
A girdle is a garment that encircles the lower torso, perhaps extending below the hips, and worn often for support. The word girdle originally meant a belt. In modern English, the term girdle is most commonly used for a form of women's foundation wear that replaced the corset in popularity...
and the forelimb
Forelimb
A forelimb is an anterior limb on an animal's body. When referring to quadrupeds , the term foreleg is often instead used....
s, an ilium
Ilium
-Places:* Ilion or, Latinized, Ilium, another name for the legendary city of Troy, hence the title of Homer's Iliad*Ilium , an ancient city in Epirus...
and elements of the hindlimbs. It was collected in the upper Hyperodapedon
Hyperodapedon
Hyperodapedon is a genus of rhynchosaur from the late Triassic period . The type species of Scaphonyx , Scaphonyx fischeri that once thought to be a dinosaur, is now known to be based on dubious material and therefore should be a nomen dubium...
biozone from the Alemoa Member of the Santa Maria Formation
Santa Maria Formation
The Santa Maria Formation is a sedimentary rock formation found in Rio Grande do Sul, Brazil. It has a late Ladinian – early Carnian age , and is notable for its fossils of early dinosaurs, including the herrerasaur Staurikosaurus, the basal saurischian Teyuwasu, and the basal sauropodomorph...
(Rosário do Sul Group) in the "Janner" (also known as "Várzea do Agudo") locality, geopark
Geopark
A Geopark is defined by the United Nations Educational, Scientific and Cultural Organization in its UNESCO Geoparks International Network of Geoparks programme as follows:...
of Paleorrota
Paleorrota
Paleorrota , is a geopark located in the center of the Brazilian state of Rio Grande do Sul. The rocks and fossils found along the route date back to the times when there was only one supercontinent Pangaea....
, dating to the Carnian
Carnian
The Carnian is the lowermost stage of the Upper Triassic series . It lasted from about 228.7 till 216.5 million years ago . The Carnian is preceded by the Ladinian and is followed by the Norian...
faunal stage
Faunal stage
In chronostratigraphy, a stage is a succession of rock strata laid down in a single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by convention have the same name, and the same boundaries.Rock...
of the early 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...
, about 230-228 million years ago.
Description
Pampadromaeus was a small bipedal animal. It shows a mosaic of basal and derived traits. It differs from other sauropodomorphs by a combination of characters. Some of these are shared with some members of the sister group of the SauropodomorphaSauropodomorpha
Sauropodomorpha is an extinct clade of long-necked, herbivorous, saurischian dinosaurs which includes the sauropods and their ancestral relatives. Sauropods generally grew to very large sizes, had long necks and tails, were quadrupedal, and became the largest animals to ever walk the Earth. The...
, the Theropoda
Theropoda
Theropoda is both a suborder of bipedal saurischian dinosaurs, and a clade consisting of that suborder and its descendants . Dinosaurs belonging to the suborder theropoda were primarily carnivorous, although a number of theropod groups evolved herbivory, omnivory, and insectivory...
: the premaxilla
Premaxilla
The incisive bone is the portion of the maxilla adjacent to the incisors. It is a pair of small cranial bones at the very tip of the jaws of many animals, usually bearing teeth, but not always. They are connected to the maxilla and the nasals....
is pointed downwards forming a subnarial gap with the maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
and the anterior-most teeth are unserrated; in the location where with theropods the fenestra promaxillaris is positioned, a small depression is present. Basal traits consist of a large skull, a short thighbone, the possession of just two sacral vertebrae and the presence of fifteen teeth in the pterygoid
Pterygoid
Pterygoid can refer to:* Pterygoid processes of the sphenoid bone** The Lateral pterygoid plate by it* a muscle such as Lateral pterygoid muscle or Medial pterygoid muscle* a branch of the Mandibular nerve...
.
There were four teeth in the premaxilla and about twenty in both the maxilla and the lower jaw for a total of eighty-eight. The teeth were large, elongated, lanceolate, slightly recurved, sharply pointed and coarsely serrated. The lower leg was much longer than the thighbone, indicating Pampadromaeus was good runner.
Etymology
Pampadromaeus was first named by Sergio F. Cabreira, Cesar L. Schultz, Jonathas S. Bittencourt, Marina B. Soares, Daniel C. Fortier, Lúcio R. Silva and Max C. Langer in 20112011 in paleontology
-Lobopods:-Arachnids:-Insects:-Newly named jawless vertebrates:-Newly named acanthodian:-Newly named cartilaginous fishes:-Newly named bony fishes:-Newly named lepospondyls:-Newly named temnospondyls:-Newly named lissamphibians:...
and the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
is Pampadromaeus barberenai. The generic name is derived from Quechua
Quechua languages
Quechua is a Native South American language family and dialect cluster spoken primarily in the Andes of South America, derived from an original common ancestor language, Proto-Quechua. It is the most widely spoken language family of the indigenous peoples of the Americas, with a total of probably...
pampa, "plain", in reference to the present landscape of the site, and Greek δρομεύς, dromeus, "runner", referring to the cursorial habits; the Latinised spelling variant dromaeus is used. The specific name honours the Brazilian paleontologist Mário Costa Barberena
Mário Costa Barberena
- Biography :Did graduate in Natural History at the Pontifícia Universidade Católica do Rio Grande do Sul in 1956 to 1959. Did his doctorate at Harvard University, in Stratigraphic and Paleontology...
.
Phylogeny
Pampadromaeus was found to be a basalBasal (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:...
sauropodomorph in four different cladistic analyses. The describers emphasized however, that this position was not strongly supported, showing the difficulties of determining the affinities of such early forms with the basal 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...
, Saurischia
Saurischia
Saurischia meaning 'lizard' and ischion meaning 'hip joint') is one of the two orders, or basic divisions, of dinosaurs. In 1888, Harry Seeley classified dinosaurs into two orders, based on their hip structure...
, Sauropodomorpha and Theropoda.