Rinconsaurus is a genus of dinosaur from the Late Cretaceous. It was a titanosaurid 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.
Temporal range: Late Cretaceous
Calvo & Riga, 2003
Like all sauropods, Rinconsaurus was a large long-necked quadrupedal 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.
Fossils of Rinconsaurus were discovered in 1997 by Gabriel Benítezin strata belonging to the Bajo de la Carpa Formation near Rincón de los Sauces, in the Neuquen 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 in the tail" in Latin, in reference to the unusual shape of the tail vertebrae, especially a strange sequence of procoelous, amphicoelous, opisthocoelous, biconvex and ultimately again procoelous vertebrae shown by one individual.
Rinconsaurus is a titanosaurid sauropod. Within the titanosaurs, Calvo 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 the Aeolosauridae, a proposed stem-based clade of titanosaurs. Rinconsaurus would form a smaller clade Rinconsauria with Muyelensaurus. It remains to be seen, however, if this classification will receive widespread acceptance.
Rinconsaurus, like all sauropods, was an herbivore. 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 cycads and conifers, discoveries published in 2005 revealed an unexpectedly wide range of monocotyledons, including palms 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.
Aeolosaurini is an extinct clade of titanosaurian dinosaurs known from the late Cretaceous period of Argentina and Brazil. Thomas Holtz (2011) assigned Adamantisaurus, Aeolosaurus, Gondwanatitan, Muyelensaurus, Panamericansaurus, Pitekunsaurus and Rinconsaurus to Aeolosauridae. Rodrigo M. Santucci and Antonio C. de Arruda-Campos (2011) in their cladistic analysis found Aeolosaurus, Gondwanatitan, Maxakalisaurus, Panamericansaurus and Rinconsaurus to be aeolosaurids.Austroposeidon
Austroposeidon is an extinct genus of titanosaurian sauropod dinosaur from the Late Cretaceous Presidente Prudente Formation of Brazil. It contains one species, Austroposeidon magnificus.Brasilotitan
Brasilotitan is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous (early Maastrichtian) Adamantina Formation of Brazil. The type species is Brasilotitan nemophagus.Cetiosauridae
Cetiosauridae is a family of sauropod dinosaurs. While traditionally a wastebasket taxon containing various unrelated species, some recent studies have found that it may represent a natural clade. Additionally, at least one study has suggested that the mamenchisaurids may represent a sub-group of the cetiosaurids, which would be termed Mamenchisaurinae.Daxiatitan
Daxiatitan is a genus of titanosaur dinosaur from the Lower Cretaceous of Lanzhou Basin, Gansu Province, northwestern China. It is known from fossils including several neck vertebrae, a shoulder blade, and a thigh bone.It was a very large dinosaur, estimated at 23–30 meters (75–98 feet). Like both Euhelopus and Huanghetitan, it had an enormously long neck.Diplodocinae
Diplodocinae is an extinct subfamily of diplodocid sauropods that existed from the Late Jurassic to Early Cretaceous of North America, Europe and South America, about 161.2 to 136.4 million years ago. Genera within the subfamily include Tornieria, Supersaurus, Leinkupal, Galeamopus, Diplodocus, Kaatedocus and Barosaurus.Cladogram of the Diplodocidae after Tschopp, Mateus, and Benson (2015).Ferganasaurus
Ferganasaurus was a genus of dinosaur first formally described in 2003 by Alifanov and Averianov. The type species is Ferganasaurus verzilini. It was a sauropod similar to Rhoetosaurus. The fossils were discovered in 1966 in Kyrgyzstan from the Balabansai Formation and date to the Callovian stage of the Middle Jurassic.Flagellicaudata
Flagellicaudata is a clade of Dinosauria. It belongs to Sauropoda and includes two families, the Dicraeosauridae and the Diplodocidae.Futalognkosaurus
Futalognkosaurus ( FOO-tə-long-ko-SAW-rəs; meaning "giant chief lizard") is a genus of titanosaurian dinosaur. The herbivorous Futalognkosaurus lived approximately 87 million years ago in the Portezuelo Formation, in what is now Argentina, of the Coniacian stage of the late Cretaceous Period. The fish and fossilized leaf debris on the site, together with other dinosaur remains, suggest a warm tropical climate in Patagonia during this period.Gravisauria
Gravisauria is a clade of sauropod dinosaurs consisting of some genera, Vulcanodontidae and Eusauropoda.Huangshanlong
Huangshanlong is a genus of mamenchisaurid dinosaurs native to the Anhui province of China. It contains a single species, Huangshanlong anhuiensis. H. anhuiensis represents, along with Anhuilong and Wannanosaurus, one of three dinosaurs fround in Anhui province.Kaijutitan
Kaijutitan (meaning "Kaiju titan" after the type of Japanese movie monsters) is a genus of basal titanosaur dinosaur from the Sierra Barrosa Formation from Neuquén Province in Argentina. The type and only species is Kaijutitan maui.Lognkosauria
Lognkosauria is a group of giant long-necked sauropod dinosaurs within the clade Titanosauria. It includes some of the largest and heaviest dinosaurs known.Pilmatueia
Pilmatueia is a diplodocoid sauropod belonging to the family Dicraeosauridae that lived in Argentina during the Early Cretaceous.Tambatitanis
Tambatitanis is an extinct genus of titanosauriform dinosaur from the Early Cretaceous (probably early Albian) of Japan. It is known from a single type species, Tambatitanis amicitiae. It was probably around 14 meters long and its mass was estimated at some 4 tonnes. It was a basal titanosauriform and possibly belonged to the Euhelopodidae.Tengrisaurus
Tengrisaurus (meaning "Tengri lizard") is a genus of lithostrotian sauropod, from the Early Cretaceous (Barremian-Aptian), of the Murtoi Formation, Russia. It was described in 2017 by Averianov & Skutschas. The type species is T. starkovi.Titanosauria
Titanosaurs (members of the group Titanosauria) were a diverse group of sauropod dinosaurs which included Saltasaurus and Isisaurus of Africa, Asia, South America, Europe and Australia. The titanosaurs were the last surviving group of long-necked sauropods, with taxa still thriving at the time of the extinction event at the end of the Cretaceous. The group includes the largest land animals known to have existed, such as Patagotitan—estimated at 37 m (121 ft) long with a weight of 69 tonnes (76 tons)—and the comparably sized Argentinosaurus and Puertasaurus from the same region. The group's name alludes to the mythological Titans of Ancient Greece, via the type genus (now considered a nomen dubium) Titanosaurus. Together with the brachiosaurids and relatives, titanosaurs make up the larger clade Titanosauriformes.Volgatitan
Volgatitan is a genus of titanosaurian sauropod dinosaur from the Early Cretaceous of the Ulyanovsk Oblast, Russia. The type and only species is Volgatitan simbirskiensis, known from seven caudal vertebrae from a single individual. It is the oldest known titanosaur from the northern hemisphere, and is considered important for being related to the Lognkosauria, a group known only from South America later in the Late Cretaceous. It was first described in November 2018 by Russian palaeontologists Alexander Averianov and Vladimir Efimov.Vulcanodontidae
The Early Jurassic sauropod dinosaurs Zizhongosaurus, Barapasaurus, Tazoudasaurus, and Vulcanodon may form a natural group of basal sauropods called the Vulcanodontidae. Basal vulcanodonts include some of the earliest known examples of sauropods. The family-level name Vulcanodontidae was erected by M.R. Cooper in 1984. In 1995 Hunt et al. published the opinion that the family is synonymous with the Barapasauridae. One of the key morphological features specific to the family is an unusually narrow sacrum.