Limaysaurus (“Limay lizard”) is a genus represented by a single species of rebbachisaurid sauropod dinosaurs, which lived during the mid-Cretaceous period, about 99.6 and 97 million years ago, in the Cenomanian, in what is now South America (northwestern Patagonia).
Salgado et al., 2004
Calvo & Salgado, 1995
Limaysaurus was a medium-sized sauropod. Gregory S. Paul in 2010 estimated its length at fifteen meters (50 ft) and its weight at seven tonnes. The neural spines on its back were very tall. The neural spines of the cervical and dorsal vertebrae are not V-shaped but they have a simple and straight form like an I. Its teeth were curved, unlike those of Diplodocus which were pencil-shaped. Another distinct characteristic of this sauropod is its phylogenetic relationship to Rebbachisaurus from Morocco. This discovery supports the theory that there was a land bridge connecting South America to Africa 100 million years ago. It shared its habitat with Andesaurus and Giganotosaurus, characterized by plains with large and shallow lagoons. The climate was mild and humid. In fossil remains of Limaysaurus, gastroliths have been found, which were used to help the stomach to grind food.
Limaysaurus includes a single type species, Limaysaurus tessonei, which was originally referred to the genus Rebbachisaurus as Rebbachisaurus tessonei, an African species, by Jorge Calvo and Leonardo Salgado in 1995. However, a generic separation was proposed by Salgado, Alberto Garrido, Sergio Cocca and Juan Cocca, and the genus Limaysaurus was named in 2004. The generic name is derived from Río Limay which borders the region and from the specific name, tessonei, in honor of Lieto Tessone, who found the first and most complete holotype. Their discovery shed some light on the distribution of Gondwanan dinosaurs in the mid-Cretaceous period. Several specimens of Limaysaurus are known, one of which (the holotype) is 80% complete, being one of the most complete Cretaceous sauropods ever found in South America.
The holotype specimen, MUCPv-205, a partial skeleton including the back of the skull, was found in 1988 by Lieto Francisco Tessone, who is honoured in the specific name. It was afterwards collected, together with MUCPv-206, a second fragmentary skeleton, by José Bonaparte. These two adult specimens likely hailed from the top of the Candeleros Formation, which is dated to the early Cenomanian age. An additional smaller specimen, MUCPv-153, was found nearby, although it belonged to the base of the Huincul Formation, from the late Cenomanian.
Limaysaurus was found 15 km (9 mi) southwest of Villa El Chocón, Picún Leufú Department, Neuquén Province, Patagonia, Argentina. The sediments belong to the Río Limay Subgroup, in Lohan Cura Formation, at Cerro Aguada del León.These beds appear to date from the Aptian-Albian interval.
The describing authors in 2004 assigned Limaysaurus to the famlily Rebbachisauridae. The rebbachisaurids are a basal clade within the Diplodocimorpha, and their remains have been found in Cretaceous-age rocks in Europe, South America, and Africa. A cladistic analysis of macronarian sauropods (Salgado et al., 2004) demonstrated close affinities between Limaysaurus, the African genera Rebbachisaurus and Nigersaurus, and the South American genera Rayososaurus and Cathartesaura. 
Andesaurus ( AN-də-SOR-əs; "Andes lizard") is a genus of basal titanosaurian sauropod dinosaur which existed during the middle of the Cretaceous Period in South America. Like most sauropods, it would have had a small head on the end of a long neck and an equally long tail. Andesaurus was a very large animal, as were many others of its relatives, which included the largest animals ever to walk the Earth.Comahuesaurus
Comahuesaurus is a genus of sauropod dinosaur of the family Rebbachisauridae. It was found in the Lohan Cura Formation, in Argentina and lived during the Early Cretaceous, Aptian to Albian. The type species is C. windhauseni, named by Carballido and colleagues in 2012. It had originally been assigned to Limaysaurus by Salgado et al. (2004), but was later assigned its own genus based on the presence of diagnostic characters in the caudal centra, pubis and ischium.Comahuesaurus is known from abundant material compared to other rebbachisaurids; 37 caudal vertebrae, three fragmentary dorsal vertebrae and multiple appendicular elements, including a right humerus, pubis, ischium and a 113 cm long left femur. In their phylogenetic analysis, Carballido et al. (2012) placed Comahuesaurus in an intermediate position between basal rebbachisaurids such as Histriasaurus and the derived clade formed by subfamilies Rebbachisaurinae and Limaysaurinae.It shares with more derived rebbachisaurids a reduced hyposphene-hypantrum system, but hadn't yet completely lost said structure; that change would happen at some further point in the evolution of the clade, as it is so far only known to be fully absent in limaysaurines.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.Dicraeosaurus
Dicraeosaurus (Gr. δικραιος, dikraios "bifurcated, double-headed" + Gr. σαυρος, sauros "lizard") is a genus of small diplodocoid sauropod dinosaur that lived in what is now Tanzania during the late Jurassic. It was named for the spines on the back of the neck. The first fossil was described by paleontologist Werner Janensch in 1914.Diplodocimorpha
Diplodocimorpha is a clade of extinct sauropod dinosaurs, existing from the Early Jurassic until the Late Cretaceous. The group includes three main families and some other genera, Rebbachisauridae, Dicraeosauridae and Diplodocidae, the latter two forming Flagellicaudata. The name was first used by Calvo & Salgado (1995), who defined it as "Rebbachisaurus tessonei sp. nov., Diplodocidae, and all descendants of their common ancestor." The group was not used often, and was synonymized with Diplodocoidea as the groups were often found to have the same content. In 2005, Mike P. Taylor and Darren Naish reviewed diplodocoid phylogeny and taxonomy, and realized that Diplodocimorpha could not be synonymized with Diplodocoidea. Whereas the former was defined node-based, the latter was branch-based. In 2015, Emanuel Tschopp, Octavio Mateus and Roger Benson published a specimen-based phylogeny on diplodocid interrelationships, and supported the separation of Diplodocimorpha. Haplocanthosaurus was found to be more basal than rebbachisaurids, and therefore outside Diplodocimorpha, but closer to Diplodocus than Saltasaurus, and therefore within Diplodocoidea. The below cladogram follows the findings of Tschopp et al.Diplodocoidea
Diplodocoidea is a superfamily of sauropod dinosaurs, which included some of the longest animals of all time, including slender giants like Supersaurus, Diplodocus, Apatosaurus, and Amphicoelias. Most had very long necks and long, whip-like tails; however, one family (the dicraeosaurids) are the only known sauropods to have re-evolved a short neck, presumably an adaptation for feeding low to the ground. This adaptation was taken to the extreme in the highly specialized sauropod Brachytrachelopan. A study of snout shape and dental microwear in diplodocoids showed that the square snouts, large proportion of pits, and fine subparallel scratches in Apatosaurus, Diplodocus, Nigersaurus, and Rebbachisaurus suggest ground-height nonselective browsing; the narrow snouts of Dicraeosaurus, Suuwassea, and Tornieria and the coarse scratches and gouges on the teeth of Dicraeosaurus suggest mid-height selective browsing in those taxa. This taxon is also noteworthy because diplodocoid sauropods had the highest tooth replacement rates of any vertebrates, as exemplified by Nigersaurus, which had new teeth erupting every 30 days.Eusauropoda
Eusauropoda (meaning "true sauropods") is a derived clade of sauropod dinosaurs. Eusauropods represent the node-based group that includes all descendant sauropods starting with the basal eusauropods of Shunosaurus, and possibly Barapasaurus, and Amygdalodon, but excluding Vulcanodon and Rhoetosaurus. The Eusauropoda was coined in 1995 by Paul Upchurch to create a monophyletic new taxonomic group that would include all sauropods, except for the vulcanodontids.Eusauropoda are herbivorous, quadrupedal, and have long necks. They have been found in South America, Europe, North America, Asia, Australia, and Africa. The temporal range of Eusauropoda ranges from the early Jurassic to the Latest Cretaceous periods. The most basal forms of eusauropods are not well known and because the cranial material for the Vulcanodon is not available, and the distribution of some of these shared derived traits that distinguish Eusauropoda is still completely clear.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.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.Itapeuasaurus
Itapeuasaurus (meaning "Itapeua lizard") is a genus of rebbachisaurid sauropod dinosaur from the Alcântara Formation from Maranhão in Brazil. The type and only species is Itapeuasaurus cajapioensis. It would have been around 10 metres (33 ft) to 15 metres (49 ft) when fully grown.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.Maraapunisaurus
Maraapunisaurus is a genus of sauropod dinosaur from the Late Jurassic Morrison Formation of western North America. It is known only from what has sometimes been estimated to be the largest dinosaur specimen ever discovered, originally named Amphicoelias fragillimus. Based on surviving descriptions of a single fossil bone, scientists have produced numerous size estimates over the years; the largest estimate M. fragillimus to have been the longest known animal at 58 metres (190 ft) in length and with a mass of 122.4 tonnes (120.5 long tons; 134.9 short tons). However, because the only fossil remains were lost at some point after being studied and described in the 1870s, evidence survived only in drawings and field notes.
More recent studies have made a number of suggestions regarding the possibility of such an animal. One analysis of the surviving evidence, and the biological plausibility of such a large land animal, has suggested that the enormous size of this animal were over-estimates due partly to typographical errors in the original 1878 description. More recently, it was suggested by paleontologist Kenneth Carpenter that the species is a rebbachisaurid, rather than a diplodocid sauropod. He therefore used Limaysaurus instead of Diplodocus as a basis for size estimates. This resulted in a smaller, 30.3 metres (99 ft) animal, and he dismissed the idea that there must have been typographical errors.Pilmatueia
Pilmatueia is a diplodocoid sauropod belonging to the family Dicraeosauridae that lived in Argentina during the Early Cretaceous.Rebbachisauridae
Rebbachisauridae is a family of sauropod dinosaurs known from fragmentary fossil remains from the Cretaceous of South America, Africa, North America, and Europe.Rebbachisaurinae
Rebbachisaurinae is a subfamily within the family Rebbachisauridae, defined to include Rebbachisaurus garasbae and exclude Limaysaurus tessonei. It was first proposed as a rank by Jose Bonaparte in 1995, to include Rebbachisaurus. Some phylogenies however, include Rebbachisaurus in a clade with Limaysaurus, and thus the subfamily was not used. In 2015, a phylogenetic analysis was conducted, and it found Rebbachisaurus instead to be closer to Nigersaurus and related genera than Limaysaurus, and thus was used to replace Nigersaurinae as Rebbachisaurinae is the older term and is named after the genus used for the formation of the family Rebbachisauridae. The 2015 cladogram of Fanti et al. is shown below.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.