Velocisaurus
Encyclopedia
Velocisaurus is a genus
of ceratosauria
n theropod dinosaur
from the Cretaceous
period of Argentina
.
In 1985 Oscar de Ferrariis and Zulma Gasparini uncovered fossils at Boca del Sapo in Neuquén province
of Patagonia
from layers of the Bajo de la Carpa Formation
, dating from the Santonian
. Among them was the right lower hind limb of a small theropod. In 1991 this dinosaur was described and named by José Bonaparte
as Velocisaurus unicus. The generic name is derived from Latin
velox, "swift", a reference to the fact that the hind leg and foot show adaptations for running. The specific name means "unique" in Latin, referring to the exceptional build of the foot.
The genus and species are based on the holotype
MUCPv 41. It is part of the collection of the Museo de la Universidad Nacional del Comahue and represents the only known remains of Velocisaurus.
Velocisaurus was probably around 1.2 meters long (4 ft), the tibia
having a length of fourteen centimeters. The foot is unique in that the middle (third) metatarsal has become the main weight-bearing element. Its upper end has thickened whereas the shafts of the adjoining second and fourth metatarsals have thinned considerably. Such a configuration is unknown for other theropods, including birds. Bonaparte explained it as an adaptation for a cursorial (running) lifestyle. The high speed would have been necessary to escape larger theropods; Bonaparte suggested that Velocisaurus was itself a omnivore
, as indicated by the fact that the sole claw found, of the fourth toe, was not trenchant but relatively straight.
Bonaparte originally assigned Velocisaurus to a family of its own, the Velocisauridae. A study of theropod relationships by Fernando Novas
and Sebastian Apesteguia in 2003 showed that Velocisaurus was a close relative of the strange ceratosaur Masiakasaurus
. These two may form a subfamily, the Velocisaurinae. In 2004 this subfamily was assigned to the Noasauridae
within the more inclusive Abelisauroidea.
In a 2001 study conducted by Bruce Rothschild and other paleontologists, 12 foot bones referred to Velocisaurus were examined for signs of stress fracture
, but none were found.
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 ceratosauria
Ceratosauria
Ceratosaurs are members of a group of theropod dinosaurs defined as all theropods sharing a more recent common ancestry with Ceratosaurus than with birds. There is presently no universally agreed upon listing of species or diagnostic characters of Ceratosauria, though they were less derived...
n 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...
from the Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
period 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...
.
In 1985 Oscar de Ferrariis and Zulma Gasparini uncovered fossils at Boca del Sapo in Neuquén province
Neuquén Province
Neuquén is a province of Argentina, located in the west of the country, at the northern end of Patagonia. It borders Mendoza Province to the north, Rio Negro Province to the southeast, and Chile to the west...
of Patagonia
Patagonia
Patagonia is a region located in Argentina and Chile, integrating the southernmost section of the Andes mountains to the southwest towards the Pacific ocean and from the east of the cordillera to the valleys it follows south through Colorado River towards Carmen de Patagones in the Atlantic Ocean...
from layers of the Bajo de la Carpa Formation
Bajo de la Carpa Formation
The Bajo de la Carpa Formation is a geologic formation that outcrops in Patagonia, in the provinces of Río Negro and Neuquén, Argentina. It is the first of two formations belonging to the Río Colorado Subgroup within the Neuquén Group...
, dating from the Santonian
Santonian
The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous epoch or Upper Cretaceous series. It spans the time between 85.8 ± 0.7 mya and 83.5 ± 0.7 mya...
. Among them was the right lower hind limb of a small theropod. In 1991 this dinosaur was described and named by José Bonaparte
José Bonaparte
José Fernando Bonaparte, Ph.D. , is an Argentine paleontologist who discovered a plethora of South American dinosaurs and mentored a new generation of Argentine paleontologists like Rodolfo Coria...
as Velocisaurus unicus. The generic name is derived from Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
velox, "swift", a reference to the fact that the hind leg and foot show adaptations for running. The specific name means "unique" in Latin, referring to the exceptional build of the foot.
The genus and species are based on 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...
MUCPv 41. It is part of the collection of the Museo de la Universidad Nacional del Comahue and represents the only known remains of Velocisaurus.
Velocisaurus was probably around 1.2 meters long (4 ft), the tibia
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....
having a length of fourteen centimeters. The foot is unique in that the middle (third) metatarsal has become the main weight-bearing element. Its upper end has thickened whereas the shafts of the adjoining second and fourth metatarsals have thinned considerably. Such a configuration is unknown for other theropods, including birds. Bonaparte explained it as an adaptation for a cursorial (running) lifestyle. The high speed would have been necessary to escape larger theropods; Bonaparte suggested that Velocisaurus was itself a omnivore
Omnivore
Omnivores are species that eat both plants and animals as their primary food source...
, as indicated by the fact that the sole claw found, of the fourth toe, was not trenchant but relatively straight.
Bonaparte originally assigned Velocisaurus to a family of its own, the Velocisauridae. A study of theropod relationships by Fernando Novas
Fernando Novas
Fernando Emilio Novas is an Argentine paleontologist working for the Comparative Anatomy Department of the Bernardino Rivadavia Natural History Argentine Museum in Buenos Aires...
and Sebastian Apesteguia in 2003 showed that Velocisaurus was a close relative of the strange ceratosaur Masiakasaurus
Masiakasaurus
Masiakasaurus was a small predatory theropod dinosaur from the Late Cretaceous of Madagascar. It was named in 2001 by Scott D. Sampson, Matthew Carrano, and Catherine A. Forster. Unlike most theropods, the front teeth of Masiakasaurus projected forward instead of straight down...
. These two may form a subfamily, the Velocisaurinae. In 2004 this subfamily was assigned to the Noasauridae
Noasauridae
Noasaurids were a group of theropod dinosaurs from the Cretaceous Period . They were generally small in size...
within the more inclusive Abelisauroidea.
In a 2001 study conducted by Bruce Rothschild and other paleontologists, 12 foot bones referred to Velocisaurus were examined for signs of stress fracture
Stress fracture
A stress fracture is one type of incomplete fracture in bones. It is caused by "unusual or repeated stress" and also heavy continuous weight on the ankle or leg...
, but none were found.