Zupaysaurus
Encyclopedia
Zupaysaurus is a genus
of early theropod dinosaur
living during the Rhaetian
stage of the Late Triassic
to Hettangian
stage of the Early Jurassic
of what is now Argentina
. Although a full skeleton has not yet been discovered, Zupaysaurus can be considered a biped
al predator, up to 4 meters (13 ft) long. It may have had two parallel crests running the length of its snout.
measured approximately 45 centimeters (18 in) in length, indicating a body length of approximately 4 meters (13 ft) from snout to tail tip. Like all known theropods, Zupaysaurus walked only on its hindlegs, leaving the forelimbs free to grasp its prey. A small gap separated the teeth of the premaxilla
ry and maxilla
ry bones of the upper jaw, and the astragalus
and calcaneum bones of the ankle
were fused together, as seen in many early theropods.
As Zupaysaurus was originally described, the skull bore two thin parallel crests on top of the skull, similar to other theropods like Dilophosaurus
and Megapnosaurus (Syntarsus) kayentakatae
. These crests were allegedly formed by the nasal
bones solely, unlike those of many other theropods which also incorporated the lacrimal
. Crests on the skull were pervasive among theropods and may have been used for communicative purposes
such as species or gender recognition. However, more recent analysis of the skull has cast doubt on the presence of these crests in Zupaysaurus. An unpublished abstract presented at a recent conference indicated the structures initially identified as crests were in fact the lacrimal bones displaced upwards during the process of fossil
ization.
word σαυρος ("lizard"). The type species
has been named Z. rougieri after Guillermo Rougier, the scientist who led the expedition which discovered and collected the holotype
(original specimen). Zupaysaurus was first described and named in the scientific journal Ameghiniana
by Argentine
paleontologists Andrea Arcucci and Rodolfo Coria
in 2003.
Originally, Zupaysaurus was classified as the earliest known tetanuran theropod due to several features of its skull and hindlimb. However, several features typical of more basal
theropods were also noted by the original authors. More recent analyses, both published and unpublished, have agreed with the latter assessment, establishing Zupaysaurus as a coelophysoid related to Segisaurus
and Dilophosaurus, probably more basal than the group containing Liliensternus
, Megapnosaurus (Syntarsus)
, and Coelophysis
. Yates (2006) found Zupaysaurus to form a group with Dilophosaurus and Dracovenator
, placing it in a monophyletic Dilophosauridae
.. But later studies , found "Zupaysaurus" to be not a dilophosaurid.
girdle, the lower right leg and ankle
, and twelve vertebrae from the neck, back, and hips. Additional material of a smaller individual found at the same site may or may not belong to Zupaysaurus. Both specimens are housed in the collection of the National University of La Rioja in La Rioja, Argentina
.
Zupaysaurus is known from the "Quebrada de los Jachaleros" locality within the Los Colorados Formation
of La Rioja
province in Argentina. This formation is usually thought to date to the Norian
stage of the Late Triassic
Period (216 to 203 Ma), but has also been assigned to the slightly younger Rhaetian
stage (203-200 Ma). The Los Colorados Formation is also home to several types of early sauropodomorph dinosaurs (including Riojasaurus
, Coloradisaurus
, and Lessemsaurus
).
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 early theropod 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...
living during the Rhaetian
Rhaetian
The Rhaetian is in geochronology the latest age of the Triassic period or in chronostratigraphy the uppermost stage of the Triassic system. It lasted from 203.6 ± 1.5 to 199.6 ± 0.6 million years ago...
stage of 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...
to Hettangian
Hettangian
The Hettangian is the earliest age or lowest stage of the Jurassic period of the geologic timescale. It spans the time between 199.6 ± 0.6 Ma and 196.5 ± 1 Ma . The Hettangian follows the Rhaetian and is followed by the Sinemurian.In Europe stratigraphy the Hettangian is a part of the time span in...
stage of the Early Jurassic
Early Jurassic
The Early Jurassic epoch is the earliest of three epochs of the Jurassic period...
of what is now 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...
. Although a full skeleton has not yet been discovered, Zupaysaurus can be considered a biped
Biped
Bipedalism is a form of terrestrial locomotion where an organism moves by means of its two rear limbs, or legs. An animal or machine that usually moves in a bipedal manner is known as a biped , meaning "two feet"...
al predator, up to 4 meters (13 ft) long. It may have had two parallel crests running the length of its snout.
Description
Zupaysaurus was a medium-sized theropod. An adult skullSkull
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...
measured approximately 45 centimeters (18 in) in length, indicating a body length of approximately 4 meters (13 ft) from snout to tail tip. Like all known theropods, Zupaysaurus walked only on its hindlegs, leaving the forelimbs free to grasp its prey. A small gap separated the teeth of 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....
ry and 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...
ry bones of the upper jaw, and the astragalus
Talus bone
-External links:* *...
and calcaneum bones of the ankle
Ankle
The ankle joint is formed where the foot and the leg meet. The ankle, or talocrural joint, is a synovial hinge joint that connects the distal ends of the tibia and fibula in the lower limb with the proximal end of the talus bone in the foot...
were fused together, as seen in many early theropods.
As Zupaysaurus was originally described, the skull bore two thin parallel crests on top of the skull, similar to other theropods like Dilophosaurus
Dilophosaurus
Dilophosaurus was a theropod dinosaur from the Sinemurian stage of the Early Jurassic Period, about 193 million years ago. The first specimens were described in 1954, but it was not until over a decade later that the genus received its current name...
and Megapnosaurus (Syntarsus) kayentakatae
Megapnosaurus
Megapnosaurus was a dinosaur of the theropod family Coelophysidae, formerly called Syntarsus , living during the Early Jurassic. It was renamed by American entomologist Dr. Michael Ivie , Polish Australian Dr...
. These crests were allegedly formed by the nasal
Nasal bone
The nasal bones are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face, and form, by their junction, "the bridge" of the nose.Each has two surfaces and four borders....
bones solely, unlike those of many other theropods which also incorporated the lacrimal
Lacrimal
The term Lacrimal can refer to:*In typography:** A type of Stroke ending *In anatomy** Lacrimal apparatus** Lacrimal artery** Lacrimal bone...
. Crests on the skull were pervasive among theropods and may have been used for communicative purposes
Animal communication
Animal communication is any behavior on the part of one animal that has an effect on the current or future behaviour of another animal. The study of animal communication, is sometimes called Zoosemiotics has played an important part in the...
such as species or gender recognition. However, more recent analysis of the skull has cast doubt on the presence of these crests in Zupaysaurus. An unpublished abstract presented at a recent conference indicated the structures initially identified as crests were in fact the lacrimal bones displaced upwards during the process of fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
ization.
Taxonomy
The name Zupaysaurus is composed of the Quechua word zupay ("devil") and the GreekGreek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
word σαυρος ("lizard"). 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...
has been named Z. rougieri after Guillermo Rougier, the scientist who led the expedition which discovered and collected the holotype
Holotype
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...
(original specimen). Zupaysaurus was first described and named in the scientific journal Ameghiniana
Ameghiniana
Ameghiniana is a peer-reviewed palaeontology journal published by the Asociación Paleontológica Argentina. The journal is named after the 19th century Italian Argentine palaeontologist Florentino Ameghino...
by Argentine
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...
paleontologists Andrea Arcucci and Rodolfo Coria
Rodolfo Coria
Dr. Rodolfo Coria is an Argentine paleontologist.He is best known for having directed the field study and co-naming of the Argentinosaurus in 1993, and the Giganotosaurus , in 1996 among other landmark South American dinosaurs...
in 2003.
Originally, Zupaysaurus was classified as the earliest known tetanuran theropod due to several features of its skull and hindlimb. However, several features typical of more 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:...
theropods were also noted by the original authors. More recent analyses, both published and unpublished, have agreed with the latter assessment, establishing Zupaysaurus as a coelophysoid related to Segisaurus
Segisaurus
Segisaurus is a genus of small coelophysoid theropod dinosaur, that measured approximately 1 metre in length. The only known specimen was discovered in 1933 in early Jurassic strata in Tsegi Canyon, Arizona, for which it was named. Segisaurus is the only dinosaur to have ever been excavated from...
and Dilophosaurus, probably more basal than the group containing Liliensternus
Liliensternus
Liliensternus was a genus of coelophysoid dinosaur from the Late Triassic period, about 205 Ma.Liliensternus was originally named in 1934 by Friedrich von Huene as a second species of Halticosaurus, H. liliensterni, the specific name honouring the German amateur paleontologist, Dr...
, Megapnosaurus (Syntarsus)
Megapnosaurus
Megapnosaurus was a dinosaur of the theropod family Coelophysidae, formerly called Syntarsus , living during the Early Jurassic. It was renamed by American entomologist Dr. Michael Ivie , Polish Australian Dr...
, and Coelophysis
Coelophysis
Coelophysis , meaning "hollow form" in reference to its hollow bones , is one of the earliest known genera of dinosaur...
. Yates (2006) found Zupaysaurus to form a group with Dilophosaurus and Dracovenator
Dracovenator
Dracovenator is the name of a genus of dinosaur from the Early Jurassic. It was a theropod which lived in what is now South Africa.The type species, Dracovenator regenti, was formally described by A.M. Yates in 2006. The genus name is a contraction of the Latin draco, "dragon", and venator, "hunter"...
, placing it in a monophyletic Dilophosauridae
Dilophosauridae
Dilophosauridae is a family of early carnivorous dinosaurs. They are well-known for their distinctive head crests, which were probably used for mating displays, or to intimidate rivals. The family was proposed by Alan Charig and Andrew Milner in 1990 to contain only the type genus, Dilophosaurus...
.. But later studies , found "Zupaysaurus" to be not a dilophosaurid.
Provenance
Only one specimen of Zupaysaurus is known to science. Designated PULR-076, it includes a nearly complete skull, the right shoulderShoulder
The human shoulder is made up of three bones: the clavicle , the scapula , and the humerus as well as associated muscles, ligaments and tendons. The articulations between the bones of the shoulder make up the shoulder joints. The major joint of the shoulder is the glenohumeral joint, which...
girdle, the lower right leg and ankle
Ankle
The ankle joint is formed where the foot and the leg meet. The ankle, or talocrural joint, is a synovial hinge joint that connects the distal ends of the tibia and fibula in the lower limb with the proximal end of the talus bone in the foot...
, and twelve vertebrae from the neck, back, and hips. Additional material of a smaller individual found at the same site may or may not belong to Zupaysaurus. Both specimens are housed in the collection of the National University of La Rioja in La Rioja, Argentina
La Rioja, Argentina
La Rioja is the capital city of the Argentine province of La Rioja, located on the east of the province. The city has a population of almost 150,000 as per the ....
.
Zupaysaurus is known from the "Quebrada de los Jachaleros" locality within the Los Colorados Formation
Los Colorados Formation
The Los Colorados Formation is a sedimentary rock formation found in La Rioja, Argentina. It has a Norian age , and is notable for its fossils of early dinosaurs, including the coelophysoid Zupaysaurus and the "prosauropods" Coloradisaurus, Lessemsaurus, and Riojasaurus.-Dinosaurs:Indeterminate...
of La Rioja
La Rioja Province (Argentina)
La Rioja is a one of the provinces of Argentina and is located in the west of the country. Neighboring provinces are from the north clockwise Catamarca, Córdoba, San Luis and San Juan.-History:...
province in Argentina. This formation is usually thought to date to the Norian
Norian
The Norian is a division of the Triassic geological period. It has the rank of an age or stage . The Norian lasted from 216.5 ± 2.0 to 203.6 ± 1.5 million years ago. It was preceded by the Carnian and succeeded by the Rhaetian.-Stratigraphic definitions:The Norian was named after the Noric Alps in...
stage of 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...
Period (216 to 203 Ma), but has also been assigned to the slightly younger Rhaetian
Rhaetian
The Rhaetian is in geochronology the latest age of the Triassic period or in chronostratigraphy the uppermost stage of the Triassic system. It lasted from 203.6 ± 1.5 to 199.6 ± 0.6 million years ago...
stage (203-200 Ma). The Los Colorados Formation is also home to several types of early sauropodomorph dinosaurs (including Riojasaurus
Riojasaurus
Riojasaurus was a herbivorous prosauropod dinosaur named after La Rioja Province in Argentina where it was found by José Bonaparte. It lived during the Late Triassic and grew to about long. Riojasaurus is the only known riojasaurid to live in South America.-Description:Riojasaurus had a heavy...
, Coloradisaurus
Coloradisaurus
Coloradisaurus is a genus of massospondylid sauropodomorph dinosaur. It lived during the Late Triassic period in what is now La Rioja Province, Argentina. It is known from the holotype PVL 5904, nearly complete skull...
, and Lessemsaurus
Lessemsaurus
Lessemsaurus is an extinct genus of sauropodomorph dinosaur named for the writer of popular science books Don Lessem. The type species, L. sauropoides, was formally described by José Fernando Bonaparte in 1999...
).
External links
- Zupaysaurus entry in The Theropod Database.