|Skeletal mount with skull based on Camarasaurus|
Britt et al., 2017
Britt et al., 2017
Moabosaurus is characterized by a suite of features including: extremely low neural spines that are thin, transverse ridges in the posterior cervical vertebrae and anterior dorsal vertebrae; strongly procoelous proximal and distal caudal vertebrae; and an ulna with well-developed lateral and medial anteroproximal ridges combined with a large olecranon process.
Moabosaurus was collected from the Dalton Wells Quarry, which is about 20 km northwest of Moab, Utah. The quarry produced parts of at least 18 individuals of Moabosaurus based on the number of braincases present, totalling over 5,500 bones. Many of the recovered bones are fragmentary due to intense trampling as evidenced by breakage and trample scratches. Another factor that degraded the bones before burial was consumption by insects. Insects, probably beetle larvae, consumed portions of the bones that were in contact with the ground, as evidenced by burrows and mandible marks. Later, the bones were transported a short distance by a stream and buried in sediments reworked from the underlying Morrison Formation. Detrital zircon crystals from the Dalton Wells Quarry yield an age of 125 million years, indicating Moabosaurus is Aptian in age.
Phylogenetic analyses in the describing article indicated that Moabosaurus is a basal titanosauriform macronarian neosauropod. Unlike other titanosauriform sauropods it has thick-walled vertebrae with large pneumatic chambers (camerate-grade) as in basal macronarians and large, spatulate teeth, as in Camarasaurus. However, a second study in 2017 placed it in the Turiasauria, thus outside of the Neosauropoda. With Turiasaurus it shares derived features of the braincase; bifurcated cervical (neck) ribs; extremely low neural spines on the cervical and anterior dorsal vertebrae; and strongly procoelous proximal caudal vertebrae.
The Dalton Wells quarry has also yielded specimens of Venenosaurus (a brachiosaurid sauropod), the theropod dinosaurs Utahraptor and Nedcolbertia, plus a tall-spined iguanodontian, and the ankylosaurian Gastonia. Non-dinosaurian taxa are rare at the quarry and are limited to fragments of a pterosaur, crocodilian, turtle, and a neochoristodere.
Apatosaurinae is the name of a subfamily of diplodocid sauropods that existed between 157 and 150 million years ago in North America. The group includes two genera for certain, Apatosaurus and Brontosaurus, with at least five species. Atlantosaurus and Amphicoelias might also belong to this group.Below is a cladogram of apatosaurinae interrelationships based on Tschopp et al., 2015.Argyrosauridae
Argyrosauridae is a family of large titanosaurian dinosaurs known from the late Cretaceous period of Argentina and Egypt. The group has been recovered as monophyletic, including the type genus Argyrosaurus as well as Paralititan.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.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).Eomamenchisaurus
Eomamenchisaurus (meaning "dawn Mamenchisaurus") is a genus of mamenchisaurid sauropod dinosaur from the Middle Jurassic of Yuanmou, Yunnan, China. The type species is E. yuanmouensis, described by Lü Junchang et al. in 2008.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.Jiutaisaurus
Jiutaisaurus is a genus of sauropod dinosaur from the Quantou Formation of China. Jiutaisaurus was a sauropod which lived during the Cretaceous. The type species, Jiutaisaurus xidiensis, was described by Wu et al. in 2006, and is based on eighteen vertebrae.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.Mierasaurus
Mierasaurus is an extinct genus of sauropod dinosaur from the Early Cretaceous of Utah, United States. The taxon was first described and named in 2017 by Rafael Royo-Torres and colleagues, from a mostly complete skeleton including a disarticulated partial skull and mandible, teeth, multiple vertebrae from along the length of the body, both scapulae, radius and ulna bones, a left manus, a complete pelvis, both femora and the entire left hindlimb. Additionally, they also referred a lower jaw and femur from juvenile individuals, which were found nearby, to the genus. Collectively, Mierasaurus is among the most completely known North American sauropods. The genus name honours Bernardo de Miera y Pacheco, the first European scientist to enter what is now Utah. The type species for Mierasaurus is Mierasaurus bobyoungi, named after Robert Glen Young, a paleontologist who researched the Early Cretaceous of Utah.Along with its closest relative Moabosaurus, also from the Early Cretaceous of Utah, Mierasaurus is among the last-surviving members of the Turiasauria, an otherwise Jurassic and European group which can be distinguished by heart-shaped teeth, slender humeri, and the presence of an extra depression on the surface of the ulnae, among other characteristics. Mierasaurus differs from Moabosaurus in characteristics such as lacking vertical ridges on its teeth, having relatively smooth bottom surfaces on its cervical vertebrae, having cervical ribs that do not prominently split into two at their tips, and lacking a bulge on the side of the femur. It is probable that the ancestors of Mierasaurus and Moabosaurus migrated, shortly before the emergence of the former, to western North America from surviving populations of turiasaurs in either Europe or eastern North America.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.Tastavinsaurus
Tastavinsaurus is a genus of sauropod dinosaur belonging to the Titanosauriformes. It is based on a partial skeleton from the Early Cretaceous of Spain. The type species is Tastavinsaurus sanzi, named in honor of the Rio Tastavins in Spain and Spanish paleontologist José Luis Sanz.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.Turiasauria
Turiasauria is an unranked clade of basal sauropod dinosaurs known from Middle Jurassic to Early Cretaceous deposits in Europe, North America, and Africa.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.