Neuquensuchus
Encyclopedia
Neuquensuchus is an extinct genus
of basal
crocodyliform
from the Santonian
-age Upper Cretaceous Bajo de la Carpa Formation
of Neuquén Province
, Argentina
. The known remains were discovered on the campus of Universidad Nacional del Comahue in the city of Neuquén. Neuquensuchus was named by Lucas E. Fiorelli and Jorge O. Calvo in a publication dated to 2007, but which became available in 2008. The type species
is N. universitas, in recognition of its discovery locality. A small, slender animal, it is the first named "protosuchian" from a Gondwana
n continent. Unlike the great majority of crocodyliforms, its shin
was longer than its thigh
, suggesting it had some running ability.
MUCPv-47, a partially articulated partial postcrania
l skeleton composed of six neck, four back, two hip, and five tail vertebrae; ribs; partial right shoulder blade
and arm; left shoulder blade and upper arm
; a partial pelvis
; and most of the right leg above the foot. Another specimen, MUCPv-161, composed of some left leg bones, was also assigned to the new genus.
It had a relatively long and slender neck. The limb bones were also slender. It was not a large animal; the upper arm bones of the type specimen measure about 10.0 centimeters
(about 3.9 in
) long, the thigh bone
about 9.4 centimeters (about 3.7 in) long, and the shin bone
about 10.5 centimeters (about 4.1 in) long. Unlike all known crocodyliforms with measurable leg bones except Shantungosuchus
, the shin was longer than the femur.
Fiorelli and Calvo ran a phylogenetic analysis
of their new genus and found it to be allied with Shantungosuchus, Sichuanosuchus
, Zosuchus
, and an unnamed form from Fruita
, Colorado
(United States
). This clade
of "protosuchians" is near the base of Mesoeucrocodylia
, which also contains modern crocodilians. Neuquensuchus is thus the first basal mesoeucrocodylian known from any Gondwanan continent (Gondwana being an ancient supercontinent composed of the modern Southern Hemisphere continents and India
). With its nearest relatives from Asia
, this raises the question of how Neuquensuchus got to South America; the authors postulate an Early Cretaceous dispersal event.
s (Dinilysia
), other crocodyliforms (Comahuesuchus
, Cynodontosuchus
, Notosuchus
, and an unnamed form), and a variety of dinosaur
s including abelisaurids
, noasaurid
(Velocisaurus
), and alvarezsaurid
(Alvarezsaurus
) theropods
, titanosaur
ians including Bonitasaura
, and bird
s (Neuquenornis
and Patagopteryx
). Neuquensuchus, a small, slender crocodyliform, had limb proportions well-suited to running
, and was probably a swift, land-living animal.
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:...
crocodyliform
Crocodyliformes
Crocodyliformes is a clade of crurotarsan archosaurs, the group often traditionally referred to as "crocodilians."In 1988, Michael J. Benton and James M. Clark argued that all traditional names for well-known groups of animals should be restricted to their crown clades, that is, used only for...
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...
-age Upper Cretaceous 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...
of 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...
, 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...
. The known remains were discovered on the campus of Universidad Nacional del Comahue in the city of Neuquén. Neuquensuchus was named by Lucas E. Fiorelli and Jorge O. Calvo in a publication dated to 2007, but which became available in 2008. 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 N. universitas, in recognition of its discovery locality. A small, slender animal, it is the first named "protosuchian" from a Gondwana
Gondwana
In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinents that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago . Gondwana is believed to have sutured between ca. 570 and 510 Mya,...
n continent. Unlike the great majority of crocodyliforms, its shin
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....
was longer than its thigh
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...
, suggesting it had some running ability.
Description
Neuquensuchus is based onHolotype
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-47, a partially articulated partial postcrania
Postcrania
Postcrania[p] in zoology and vertebrate paleontology refers to all or part of the skeleton apart from the skull. Frequently, fossil remains, e.g...
l skeleton composed of six neck, four back, two hip, and five tail vertebrae; ribs; partial right shoulder blade
Scapula
In anatomy, the scapula , omo, or shoulder blade, is the bone that connects the humerus with the clavicle ....
and arm; left shoulder blade and upper arm
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
; a partial pelvis
Pelvis
In human anatomy, the pelvis is the lower part of the trunk, between the abdomen and the lower limbs .The pelvis includes several structures:...
; and most of the right leg above the foot. Another specimen, MUCPv-161, composed of some left leg bones, was also assigned to the new genus.
It had a relatively long and slender neck. The limb bones were also slender. It was not a large animal; the upper arm bones of the type specimen measure about 10.0 centimeters
Centimetre
A centimetre is a unit of length in the metric system, equal to one hundredth of a metre, which is the SI base unit of length. Centi is the SI prefix for a factor of . Hence a centimetre can be written as or — meaning or respectively...
(about 3.9 in
Inch
An inch is the name of a unit of length in a number of different systems, including Imperial units, and United States customary units. There are 36 inches in a yard and 12 inches in a foot...
) long, the thigh bone
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...
about 9.4 centimeters (about 3.7 in) long, and the shin bone
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....
about 10.5 centimeters (about 4.1 in) long. Unlike all known crocodyliforms with measurable leg bones except Shantungosuchus
Shantungosuchus
Shantungosuchus is an extinct genus of Cretaceous crocodyliform found in China. It includes three species: Shantungosuchus chuhsienensis, and S. brachycephalus, which were both described by Yang Zhongjian – usually referred to as "Young" – in 1961 and 1982, and S. hangjinensis, which...
, the shin was longer than the femur.
Fiorelli and Calvo ran a phylogenetic analysis
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
of their new genus and found it to be allied with Shantungosuchus, Sichuanosuchus
Sichuanosuchus
Sichuanosuchus is an extinct genus of crocodylomorph from the Late Jurassic and possibly Early Cretaceous of China.-References:* Chinese Fossil Vertebrates by Spencer G. Lucas...
, Zosuchus
Zosuchus
Zosuchus is a genus of basal, Late Cretaceous crocodyliform from the Redbeds of Zos Canyon in the Gobi Desert of Mongolia. It was discovered by expeditions organized by the American Museum of Natural History, and described by palaeontologists Diego Pol and Mark Norell.The type species is Z...
, and an unnamed form from Fruita
Fruita, Colorado
The City of Fruita is a Home Rule Municipality located in the western part of Mesa County, Colorado, in the United States. It is part of the Grand Junction Metropolitan Statistical Area and within the Grand Valley...
, Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
(United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
). This clade
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 "protosuchians" is near the base of Mesoeucrocodylia
Mesoeucrocodylia
Mesoeucrocodylia is the name of the clade that includes Eusuchia and the paraphyletic group Mesosuchia. The group appeared during the Early Jurassic, and continues to the present day....
, which also contains modern crocodilians. Neuquensuchus is thus the first basal mesoeucrocodylian known from any Gondwanan continent (Gondwana being an ancient supercontinent composed of the modern Southern Hemisphere continents and India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
). With its nearest relatives from Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
, this raises the question of how Neuquensuchus got to South America; the authors postulate an Early Cretaceous dispersal event.
Paleobiology and paleoecology
Neuquensuchus shared its environment with a variety of animals, including snakeSnake
Snakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales...
s (Dinilysia
Dinilysia
Dinilysia is an extinct genus of snake from the Late Cretaceous of South America. The snake reached a length of 6-10 feet and preyed on smaller animals...
), other crocodyliforms (Comahuesuchus
Comahuesuchus
Comahuesuchus is an extinct genus of notosuchian crocodylomorph from the Late Cretaceous of Argentina. It was described by palaeontologist José Bonaparte in 1991.The type species is C. brachybuccalis.- Material :...
, Cynodontosuchus
Cynodontosuchus
Cynodontosuchus is an extinct genus of baurusuchid mesoeucrocodylian. Fossils have been found from Argentina of Late Cretaceous age from the Bajo de la Carpa Formation as well as the Pichi Picun Leufu Formation...
, Notosuchus
Notosuchus
Notosuchus is an extinct genus of South American notosuchian crocodylomorph. It was terrestrial, living approximately 85 million years ago in the Coniacian or Santonian stages of the Late Cretaceous. Remains have been found in the Bajo de la Carpa Formation in Patagonia, Argentina. First named in...
, and an unnamed form), and a variety of 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 including abelisaurids
Abelisauridae
Abelisauridae is a family of ceratosaurian theropod dinosaurs. Abelisaurids thrived during the Cretaceous Period, on the ancient southern supercontinent of Gondwana, and today their fossil remains are found on the modern continents of Africa and South America, as well as on the Indian...
, noasaurid
Noasauridae
Noasaurids were a group of theropod dinosaurs from the Cretaceous Period . They were generally small in size...
(Velocisaurus
Velocisaurus
Velocisaurus is a genus of ceratosaurian 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...
), and alvarezsaurid
Alvarezsauridae
Alvarezsauridae is an enigmatic family of small, long-legged running dinosaurs. Although originally thought to represent the earliest known flightless birds, a consensus of recent work suggests that they are primitive members of the Maniraptora. Other work found them to be the sister group to the...
(Alvarezsaurus
Alvarezsaurus
Alvarezsaurus is a genus of small alvarezsaurid dinosaur from the Late Cretaceous period of Argentina, approximately 86 - 83 million years ago. Estimates suggest that it measured about 2 meters in length and weighed approximately 20 kg...
) theropods
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...
, titanosaur
Titanosaur
Titanosaurs were a diverse group of sauropod dinosaurs, which included Saltasaurus and Isisaurus. It includes some of the heaviest creatures ever to walk the earth, such as Argentinosaurus and Paralititan — which some believe have weighed up to 100 tonnes...
ians including Bonitasaura
Bonitasaura
Bonitasaura is a titanosaurian dinosaur hailing from uppermost layers of the Late Cretaceous Bajo de la Carpa Formation, Neuquen Group, located in Río Negro Province, Northwestern Patagonia, Argentina...
, and bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s (Neuquenornis
Neuquenornis
Neuquenornis volans was an enantiornithine bird which lived during the Late Cretaceous in today's Patagonia, Argentina. It is presently the only known species of the genus Neuquenornis. Its fossils were found in the Santonian Bajo de la Carpa Formation, dating from about 85-83 million years ago....
and Patagopteryx
Patagopteryx
Patagopteryx is an extinct monotypic genus of birds that lived during the Late Cretaceous, around 80 mya, in what is now the Sierra Barrosa in northwestern Patagonia, Argentina. About the size of a chicken, it is the earliest known unequivocal example of secondary flightlessness: its skeleton...
). Neuquensuchus, a small, slender crocodyliform, had limb proportions well-suited to running
Cursorial
Cursorial is a biological term that describes an organism as being adapted specifically to run. It is typically used in conjunction with an animal's feeding habits or another important adaptation. For example, a horse can be considered a "cursorial grazer", while a wolf may be considered a...
, and was probably a swift, land-living animal.
See also
- List of crurotarsans
- SichuanosuchusSichuanosuchusSichuanosuchus is an extinct genus of crocodylomorph from the Late Jurassic and possibly Early Cretaceous of China.-References:* Chinese Fossil Vertebrates by Spencer G. Lucas...
- ZosuchusZosuchusZosuchus is a genus of basal, Late Cretaceous crocodyliform from the Redbeds of Zos Canyon in the Gobi Desert of Mongolia. It was discovered by expeditions organized by the American Museum of Natural History, and described by palaeontologists Diego Pol and Mark Norell.The type species is Z...
- TzaganosuchusTzaganosuchusTzaganosuchus is an extinct genus of fossil crocodile from the Gobi Desert of southern/southeastern Mongolia. The type and only known species for this genus, Tzaganosuchus infansis was discovered during a joint paleontological expedition conducted by the Soviet Union and Mongolia...