Sidersaura Temporal range: Late Cretaceous, | |
---|---|
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | † Sauropodomorpha |
Clade: | † Sauropoda |
Superfamily: | † Diplodocoidea |
Family: | † Rebbachisauridae |
Genus: | † Sidersaura Lerzo et al., 2024 |
Species: | †S. marae |
Binomial name | |
†Sidersaura marae Lerzo et al., 2024 | |
Sidersaura (meaning "star lizard") is an extinct genus of rebbachisaurid sauropod dinosaur from the Late Cretaceous Huincul Formation of Argentina. The genus contains a single species, S. marae, known from the remains of four individuals. Sidersaura represents one of the largest known rebbachisaurids.
The Sidersaura fossil material was discovered in 2012 in sediments from the base of the Huincul Formation (Barda Atravesada de Las Campanas locality) in Cañadón de las Campanas near Villa El Chocón of Neuquén Province, Argentina. The bones were then excavated over the course of five years, during which the holotype of the giant carcharodontosaurid Meraxes was also found. [1] [2]
The holotype specimen, MMCh-PV 70, belonging to a mature individual, consists of a braincase fused to the skull roof and partial neurocranium, partial dorsal vertebrae, fourteen caudal vertebrae with some haemal arches, a partial left scapula, right pubic peduncle, part of both tibiae and fibulae, and several bones from the feet, including metatarsals, phalanges, ungual phalanges. [1]
Additional specimens were also assigned as paratypes. MMCh-PV 236, belonging to a mature individual, was found in close proximity to the holotype of Meraxes, about 20 metres (66 ft) from the other Sidersaura specimens. It includes an indeterminate vertebra (likely a sacral or caudal), a dorsal rib, two metacarpals, a partial pelvic girdle including an incomplete ilium, ischia, and pubes, and the left femur and fibula. Additional bones of this specimen, including sacral neural arches, caudal vertebrae, the right femur, left tibia, right fibula, and a metatarsal, have also been found but are currently not prepared. MMCh-PV 307, also from a mature individual, is a partial left fibula. MMCh-PV 309, belonging to a juvenile individual, consists of a dorsal centrum. [1]
In 2024, Lerzo et al. described Sidersaura marae as a new genus and species of rebbachisaurid sauropod based on these fossil remains. The generic name, "Sidersaura", combines the Latin word "sidus, sideris", meaning "star"—in reference to the shape of some of the preserved haemal arches—and "saura", the feminine declination of the Greek word "sauros", meaning "lizard" or "reptile". The specific name, "marae", honors fossil preparator and MMCh-PV director Mara Ripoll. [1] [3]
Sidersaura was a very large rebbachisaurid. Aside from the controversial giant sauropod Maraapunisaurus which may be a rebbachisaurid, Sidersaura may represent one of the largest known members of this group, at around 18–20 metres (59–66 ft) long and 15 tons in weight. [2] [4]
The left femur (MMCh-PV 236) of Sidersaura is 1.55 metres (5.1 ft) long, thus representing the largest known rebbachisaurid femur; other large femurs include those of Limaysaurus, at 1.44 metres (4.7 ft) long, and Comahuesaurus, at 1.13 metres (3.7 ft) long. The femur of Amphicoelias , a diplodocid from the Late Jurassic Morrison Formation of the United States estimated at 18 metres (59 ft) in length, was similar in size, at 1.52 metres (5.0 ft). [1] [5]
Several unique features are seen in the Sidersaura fossil material that differentiate it from all other species. For example, Sidersaura is the first rebbachisaurid known to have a frontoparietal foramen, a feature otherwise seen only in dicraeosaurids, the related Apatosaurus , and Spinophorosaurus , a basal sauropod. The crescent-shaped calcaneum is different from any other sauropod, more closely resembling basal sauropods such as Vulcanodon than other neosauropods. The haemal arches are also unusual, bearing two sets of projections that give them a star shape. While this is not seen in any other named species, an unnamed rebbachisaurid specimen from the geologically older Candeleros Formation—originally described in 2011 as belonging to a titanosaur—also has a similar haemal arch morphology, indicating the two taxa may be related. [6] Some features of the caudal vertebrae are also seen in titanosaurs, having been previously thought to be synapomorphies of that group. [1]
Lerzo et al. (2024) recovered Sidersaura as a rebbachisaurid member of the sauropod clade Diplodocoidea, as the sister taxon to Itapeuasaurus in a clade also containing Zapalasaurus . This group is not particularly closely related to Limaysaurus and Cathartesaura (sometimes recovered in a clade called Limaysaurinae), the two other rebbachisaurids named from the Huincul Formation. Sidersaura was one of the last rebbachisaurids known before the clade went extinct at the end of the Turonian age. The results of the phylogenetic analyses of Lerzo et al. are shown in the cladogram below: [1]
Diplodocoidea |
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Sidersaura is known from the Late Cretaceous Huincul Formation of Río Negro Province, Argentina. [1] Many dinosaurs, including fellow rebbachisaurids ( Cathartesaura and Limaysaurus ), [7] titanosaurs ( Argentinosaurus , Bustingorrytitan , Chucarosaurus , and Choconsaurus ), [8] carcharodontosaurids ( Mapusaurus , Meraxes , and Taurovenator ), [9] a megaraptoran ( Aoniraptor ), abelisaurids ( Skorpiovenator , Tralkasaurus , and Ilokelesia ), an elaphrosaurine ( Huinculsaurus ), [10] a paravian ( Overoraptor ), and the unusual avetheropod Gualicho have also been named from the formation. [11] [12] Remains of unenlagiids, iguanodonts, and elasmarian ornithopods are also known. [13]
Argentinosaurus is a genus of giant sauropod dinosaur that lived during the Late Cretaceous period in what is now Argentina. Although it is only known from fragmentary remains, Argentinosaurus is one of the largest known land animals of all time, perhaps the largest, measuring 30–35 metres (98–115 ft) long and weighing 65–80 tonnes. It was a member of Titanosauria, the dominant group of sauropods during the Cretaceous. It is widely regarded by many paleontologists as the biggest dinosaur ever, and perhaps lengthwise the longest animal ever, though both claims have no concrete evidence yet.
Agustinia is a genus of sauropod dinosaur from the Early Cretaceous of South America. The genus contains a single species, Agustinia ligabuei, known from a single specimen that was recovered from the Lohan Cura Formation of Neuquén Province in Argentina. It lived about 116–108 million years ago, in the Aptian–Albian stages of the Early Cretaceous Period.
Limaysaurus is a genus represented by a single species of rebbachisaurid sauropod dinosaurs, which lived during the mid-Cretaceous period, about 99.6 to 97 million years ago, in the Cenomanian, in what is now South America.
Andesaurus is a genus of basal titanosaurian sauropod dinosaur which existed during the middle of the Cretaceous Period in South America. Like most sauropods, belonging to one of the largest animals ever to walk the Earth, it would have had a small head on the end of a long neck and an equally long tail.
The Candeleros Formation is a geologic formation that crops out in the Río Negro, Neuquén, and Mendoza provinces of northern Patagonia, Argentina. It is the oldest formation in the Neuquén Group and belongs to the Rio Limay Subgroup. Formerly that subgroup was treated as a formation, and the Candeleros Formation was known as the Candeleros Member.
Neuquensaurus is a genus of saltasaurid sauropod dinosaur that lived in the Late Cretaceous, about 80 million years ago in Argentina in South America. Its fossils were recovered from outcrops of the Anacleto Formation around Cinco Saltos, near the Neuquén river from which its name is derived.
Rocasaurus is a genus of titanosaurian sauropod that lived in South America. Rocasaurus was discovered in Argentina in 2000, within the Allen Formation which is dated to be middle Campanian to early Maastrichtian in age. This genus grew up to 8 metres (26 ft) long, making it one of the smaller sauropods. It seems to be closely related to saltasaurid dinosaurs, like Saltasaurus and Neuquensaurus.
The Huincul Formation is a geologic formation of Late Cretaceous age of the Neuquén Basin that outcrops in the Mendoza, Río Negro and Neuquén Provinces of northern Patagonia, Argentina. It is the second formation in the Río Limay Subgroup, the oldest subgroup within the Neuquén Group. Formerly that subgroup was treated as a formation, and the Huincul Formation was known as the Huincul Member.
Cathartesaura is a genus of rebbachisaurid sauropod dinosaur hailing from the Late Cretaceous strata of the Huincul Formation, at the "La Buitrera" locality, in the Neuquén Basin of Río Negro Province, Argentina. The fossil remains, described by Gallina and Apesteguía in 2005, consist of a partial skeleton including vertebrae and limb bones. These were found at the base of the formation, which spans the Cenomanian and Coniacian epochs, in mudstone and sandstone levels.
Amargatitanis is a genus of dicraeosaurid sauropod dinosaur from the Barremian-age La Amarga Formation of Neuquén, Argentina. It is known from a single, incomplete postcranial skeleton consisting of a partial hindlimb, ischium, and two vertebrae. These remains were unearthed by Argentine paleontologist José Bonaparte in 1983 during an expedition by the Museo Argentino de Ciencias Naturales and later described as a new genus and species, Amargatitanis macni by Sebastián Apesteguía. The genus name comes from the words Amarga, where the fossils were collected, and titanis meaning "titan". Its species name is in reference to the MACN, where the remains are stored.
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.
Katepensaurus is an extinct genus of rebbachisaurid sauropod dinosaur known from the Late Cretaceous of south-central Chubut Province of central Patagonia, Argentina. It contains a single species, Katepensaurus goicoecheai.
Leinkupal is a genus of diplodocine sauropod known from the Early Cretaceous of the Bajada Colorada Formation, southeastern Neuquén Basin in the Neuquén Province of Argentina. It contains a single species, Leinkupal laticauda.
Choconsaurus is an extinct genus of herbivorous sauropod dinosaur belonging to the group Titanosauriformes, which lived in the area of present-day Argentina at the end of the Cretaceous.
Tralkasaurus is a genus of abelisaurid dinosaur from the Huincul Formation from Río Negro Province in Argentina. The type and only species is Tralkasaurus cuyi, named in 2020 by Mauricio Cerroni and colleagues based on an incomplete skeleton. A medium-sized abelisaurid, Tralkasaurus exhibits a conflicting blend of characteristics found among the early-diverging abelisauroids with others that characterize the highly specialized clade Brachyrostra, and thus its position within the clade is poorly-resolved.
Kaikaifilusaurus is an extinct genus of rhynchocephalians in the family Sphenodontidae from the Late Cretaceous of South America. Fossils of the genus were found in Cenomanian sediments of the Candeleros Formation and Turonian layers of the Huincul Formation, both of the Neuquén Basin and the Albian strata of the Cerro Barcino Formation in the Cañadón Asfalto Basin, all in Patagonia, Argentina. The genus contains two species, K. minimus and the type species K. calvoi.
Overoraptor is an extinct genus of paravian theropod of uncertain affinities from the Late Cretaceous Huincul Formation of Argentinian Patagonia. The genus contains a single species, O. chimentoi, known from several bones of the hands, feet, and hips alongside some vertebrae.
Meraxes is a genus of large carcharodontosaurid theropod dinosaur from the Late Cretaceous Huincul Formation of Patagonia, Argentina. The genus contains a single species, Meraxes gigas.
Chucarosaurus is an extinct genus of titanosaurian dinosaur from the Late Cretaceous Huincul Formation of Argentina. The genus contains a single species, C. diripienda, known from various limb and pelvic bones.
Chakisaurus is an extinct genus of elasmarian ornithopod dinosaur from the Late Cretaceous Huincul Formation of Argentina. The genus contains a single species, C. nekul, known from multiple partial skeletons belonging to individuals of different ages. Chakisaurus represents the first ornithischian species to be named from the Huincul Formation.