Rinconsaurus
Encyclopedia
Rinconsaurus is a genus
of dinosaur
from the Late Cretaceous
. It was a titanosaur
id sauropod which lived in what is now Argentina
. The type species
, Rinconsaurus caudamirus, was described by Calvo and Riga in 2003, and is based on three partial skeletons.
al animal, with a long, whip-like tail and four pillar-like legs. Rinconsaurus was an unusually slender sauropod. Although fossil discoveries are incomplete, and no complete necks or heads have been found, fully grown Rinconsaurus are estimated to have been 11 meters (36 ft) long and approximately 2.5 meters (8 ft) high at the shoulder. Though only a portion of one skull has been recovered, Rinconsaurus may have had a long, narrow skull, based on fossil evidence of the skulls of related titanosaurs.
province of Argentina. The fossils, which consisted of three individuals (two adults and one juvenile), were excavated by Jorge Calvo of the Paleontology Museum of the National University of Comahue.
The type
, and only known species, Rinconsaurus caudamirus, was described by Calvo and Bernardo J. González Riga of the Paleovertebrate Laboratory in Mendoza, Argentina, in 2003. The authors noted derived traits unique to the genus, including distinctive tail vertebrae with bony processes. The fossil remains included vertebrae, limb bones, scapula
, hip bones (pubis
, ilium
, and ischium) and several ribs. Cranial fragments, a mandible
, and two teeth have also been discovered. These teeth resemble those of another titanosaurid, Malawisaurus dixeyi
.
The generic name refers to Rincón de los Sauces, where the fossils were discovered, while the specific name, caudamirus, means "amazing tail", in reference to the unusual shape of the tail vertebrae.
id sauropod. Within the titanosaurs, Coria and Riga regard this dinosaur as closely related to Aeolosaurus
based on several derived traits. In 2007, Casal et al. assigned Rinconsaurus, Gondwanatitan
, and Aeolosaurus to Aeolosaurini, a proposed stem-based clade
of titanosaurs. It remains to be seen, however, if this classification will receive widespread acceptance.
. Fossilized dung
associated with late Cretaceous titanosaurids has revealed phytoliths, silicified plant fragments, that offer clues to a broad, unselective plant diet. Besides the plant remains that might have been expected, such as cycad
s and conifers, discoveries published in 2005 revealed an unexpectedly wide range of monocotyledon
s, including palm
s and grasses (Poaceae
), including ancestors of rice
and bamboo
, which has given rise to speculation that herbivorous dinosaurs and grasses co-evolved
.
Titanosaurid teeth are usually spatulate (spoon-shaped) or shaped like pegs. Teeth found in association with Rinconsaurus have been described as "pencil-chisel-like teeth" and had sharply inclined wear facets. Without the ability to grind food, Rinconsaurus, like other sauropods, would have stripped foliage.
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 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 Late 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...
. It was a 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...
id sauropod which lived in 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...
. 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...
, Rinconsaurus caudamirus, was described by Calvo and Riga in 2003, and is based on three partial skeletons.
Description
Like all sauropods, Rinconsaurus was a large long-necked quadrupedQuadruped
Quadrupedalism is a form of land animal locomotion using four limbs or legs. An animal or machine that usually moves in a quadrupedal manner is known as a quadruped, meaning "four feet"...
al animal, with a long, whip-like tail and four pillar-like legs. Rinconsaurus was an unusually slender sauropod. Although fossil discoveries are incomplete, and no complete necks or heads have been found, fully grown Rinconsaurus are estimated to have been 11 meters (36 ft) long and approximately 2.5 meters (8 ft) high at the shoulder. Though only a portion of one skull has been recovered, Rinconsaurus may have had a long, narrow skull, based on fossil evidence of the skulls of related titanosaurs.
Discovery and species
Fossils of Rinconsaurus were discovered in 1997 by Gabriel Benítez near Rincón de los Sauces, in the NeuquenNeuquén
Neuquén is the name of the following things:* Neuquén, Argentina* Neuquén Province* Neuquén River* Neuquén Group...
province of Argentina. The fossils, which consisted of three individuals (two adults and one juvenile), were excavated by Jorge Calvo of the Paleontology Museum of the National University of Comahue.
The type
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...
, and only known species, Rinconsaurus caudamirus, was described by Calvo and Bernardo J. González Riga of the Paleovertebrate Laboratory in Mendoza, Argentina, in 2003. The authors noted derived traits unique to the genus, including distinctive tail vertebrae with bony processes. The fossil remains included vertebrae, limb bones, scapula
Scapula
In anatomy, the scapula , omo, or shoulder blade, is the bone that connects the humerus with the clavicle ....
, hip bones (pubis
Pubis (bone)
In vertebrates, the pubic bone is the ventral and anterior of the three principal bones composing either half of the pelvis.It is covered by a layer of fat, which is covered by the mons pubis....
, 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 ,...
, and ischium) and several ribs. Cranial fragments, a mandible
Mandible
The mandible pronunciation or inferior maxillary bone forms the lower jaw and holds the lower teeth in place...
, and two teeth have also been discovered. These teeth resemble those of another titanosaurid, Malawisaurus dixeyi
Malawisaurus
Malawisaurus was a genus of sauropod dinosaur . It lived in what is now Africa, specifically Malawi, during the Aptian age of the Early Cretaceous Period. It is one of the few titanosaurs for which skull material has been found.It was named by Louis L. Jacobs and colleagues, and was originally...
.
The generic name refers to Rincón de los Sauces, where the fossils were discovered, while the specific name, caudamirus, means "amazing tail", in reference to the unusual shape of the tail vertebrae.
Classification
Rinconsaurus is a titanosaurTitanosaur
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...
id sauropod. Within the titanosaurs, Coria and Riga regard this dinosaur as closely related to Aeolosaurus
Aeolosaurus
Aeolosaurus is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Period of what is now South America. Like most sauropods, it would have been a quadrupedal herbivore with a long neck and tail...
based on several derived traits. In 2007, Casal et al. assigned Rinconsaurus, Gondwanatitan
Gondwanatitan
Gondwanatitan was a titanosaurian sauropod dinosaur. Gondwanatitan was found in Brazil, at the time part of the southern supercontinent Gondwana , in the late Cretaceous Period . Like some other sauropods, Gondwanatitan was tall and ate tough shoots and leaves off of the tops of trees. G...
, and Aeolosaurus to Aeolosaurini, a proposed stem-based 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 titanosaurs. It remains to be seen, however, if this classification will receive widespread acceptance.
Diet
Rinconsaurus, like all sauropods, was an herbivoreHerbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...
. Fossilized dung
Coprolite
A coprolite is fossilized animal dung. Coprolites are classified as trace fossils as opposed to body fossils, as they give evidence for the animal's behaviour rather than morphology. The name is derived from the Greek words κοπρος / kopros meaning 'dung' and λιθος / lithos meaning 'stone'. They...
associated with late Cretaceous titanosaurids has revealed phytoliths, silicified plant fragments, that offer clues to a broad, unselective plant diet. Besides the plant remains that might have been expected, such as cycad
Cycad
Cycads are seed plants typically characterized by a stout and woody trunk with a crown of large, hard and stiff, evergreen leaves. They usually have pinnate leaves. The individual plants are either all male or all female . Cycads vary in size from having a trunk that is only a few centimeters...
s and conifers, discoveries published in 2005 revealed an unexpectedly wide range of monocotyledon
Monocotyledon
Monocotyledons, also known as monocots, are one of two major groups of flowering plants that are traditionally recognized, the other being dicotyledons, or dicots. Monocot seedlings typically have one cotyledon , in contrast to the two cotyledons typical of dicots...
s, including palm
Arecaceae
Arecaceae or Palmae , are a family of flowering plants, the only family in the monocot order Arecales. There are roughly 202 currently known genera with around 2600 species, most of which are restricted to tropical, subtropical, and warm temperate climates...
s and grasses (Poaceae
Poaceae
The Poaceae is a large and nearly ubiquitous family of flowering plants. Members of this family are commonly called grasses, although the term "grass" is also applied to plants that are not in the Poaceae lineage, including the rushes and sedges...
), including ancestors of rice
Rice
Rice is the seed of the monocot plants Oryza sativa or Oryza glaberrima . As a cereal grain, it is the most important staple food for a large part of the world's human population, especially in East Asia, Southeast Asia, South Asia, the Middle East, and the West Indies...
and bamboo
Bamboo
Bamboo is a group of perennial evergreens in the true grass family Poaceae, subfamily Bambusoideae, tribe Bambuseae. Giant bamboos are the largest members of the grass family....
, which has given rise to speculation that herbivorous dinosaurs and grasses co-evolved
Co-evolution
In biology, coevolution is "the change of a biological object triggered by the change of a related object." Coevolution can occur at many biological levels: it can be as microscopic as correlated mutations between amino acids in a protein, or as macroscopic as covarying traits between different...
.
Titanosaurid teeth are usually spatulate (spoon-shaped) or shaped like pegs. Teeth found in association with Rinconsaurus have been described as "pencil-chisel-like teeth" and had sharply inclined wear facets. Without the ability to grind food, Rinconsaurus, like other sauropods, would have stripped foliage.
External links
- Rinconsaurus caudamirus gen. et sp. nov., a new titanosaurid (Dinosauria, Sauropoda) from the Late Cretaceous of Patagonia, Argentina Original paper describing Rinconsaurus (technical)
- Saltasauridae from Thescelosaurus!
- Rinconsaurus DinoData.org