Somphospondyli

Somphospondylans are an extinct clade of titanosauriform sauropods that lived throughout the world from the Late Jurassic through the Cretaceous in North America, South America, Europe, Asia, Africa and Australia. The group can be defined as "the most inclusive clade that includes Saltasaurus loricatus but excludes Brachiosaurus altithorax". Features found as diagnostic of this clade by Mannion et al. (2013) include the possession of at least 15 cervical vertebrae; a bevelled radius bone end; sacral vertebrae with camellate internal texture; convex posterior articular surfaces of middle to posterior caudal vertebrae; biconvex distal caudal vertebrae; humerus anterolateral corner "squared"; among multiple others. [1]

Somphospondylans
Temporal range: Late Jurassic to Late Cretaceous, 155–66 Ma
Skeleton of Qiaowanlong kangxii
Skeleton of Qiaowanlong
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Saurischia
Suborder: Sauropodomorpha
Clade: Sauropoda
Clade: Camarasauromorpha
Clade: Titanosauriformes
Clade: Somphospondyli
Wilson & Sereno, 1998
Genera

References

  1. ^ Mannion, P.D.; Upchurch, P.; Barnes, R.N.; Mateus, O. (2013). "Osteology of the Late Jurassic Portuguese sauropod dinosaur Lusotitan atalaiensis (Macronaria) and the evolutionary history of basal titanosauriforms". Zoological Journal of the Linnean Society. 168: 98–206. doi:10.1111/zoj.12029.
Agustinia

Agustinia is a genus of sauropod dinosaurs from the Early Cretaceous Period of South America. It contains the single species Agustinia ligabuei, a single specimen of which was recovered from the Lohan Cura Formation of Neuquen Province in Argentina, thought to date from the late Aptian to Albian stages of the Early Cretaceous Period, between 116 and 100 million years ago.The name Agustinia honors the discoverer of the specimen, Agustin Martinelli. This dinosaur was originally named in a 1998 abstract written by famous Argentine paleontologist Jose Bonaparte. The original generic name was "Augustia", which, as it turned out, was already preoccupied by a beetle (see also: Megapnosaurus, Protognathosaurus). Bonaparte changed the name to Agustinia in a full paper published in 1999. There is one named species (A. ligabuei), which is named in honor of Dr. Giancarlo Ligabue, a philanthropist who provided financial support to the expedition which recovered the remains.

Astrophocaudia

Astrophocaudia is a genus of somphospondylan sauropod known from the late Early Cretaceous (Albian stage) of Texas, United States. Its remains were discovered in the Trinity Group. The type species is Astrophocaudia slaughteri, described in 2012 by Michael D. D’Emic while a doctoral student at the Museum of Paleontology of the University of Michigan, USA.

Austrosaurus

Austrosaurus (meaning "Southern lizard") was an extinct genus of sauropod dinosaur from the Allaru Formation and Winton Formation, from the early Cretaceous (110-105 million years ago) of Central-Western Queensland in Australia.

Euhelopodidae

Euhelopodidae is a family of sauropod dinosaurs which includes the genus Euhelopus. All known euhelopodids lived in what is now East Asia. The family name was first proposed by American paleontologist Alfred Sherwood Romer in 1956. The four genera Chiayusaurus, Omeisaurus, Tienshanosaurus, and Euhelopus were the original proposed euhelopodines (subfamily Euhelopodinae). Other genera such as Mamenchisaurus and Shunosaurus were formerly placed within this family, but these are now regarded as more basal sauropods.

Michael D'Emic (2012) formulated the first phylogenetic definition of Euhelopodidae, defining it as the clade containing "neosauropods more closely related to Euhelopus zdanskyi than to Neuquensaurus australis". Below is a cladogram presenting the cladistic hypothesis of Euhelopodidae proposed by D'Emic.

Gobititan

Gobititan is a genus of herbivorous sauropod dinosaur from the Barremian faunal stage of the Early Cretaceous, approximately 129-125 million years ago. The name of this genus, is derived from the Gobi desert region and the Titans of Greek mythology, which is a reference to its large body size. The specific name shenzhouensis, is derived from "Shenzhou", an ancient name for China.

Huabeisaurus

Huabeisaurus (, meaning "North China lizard") was a genus of dinosaur from the Late Cretaceous (Cenomanian to Maastrichtian stages, around 99.7–70.6 million years ago). It was a sauropod which lived in what is present-day northern China. The type species, Huabeisaurus allocotus, was first described by Pang Qiqing and Cheng Zhengwu in 2000. Huabeisaurus is known from numerous remains found in the 1990s, which include teeth, partial limbs and vertebrae. Due to its relative completeness, Huabeisaurus represents a significant taxon for understanding sauropod evolution in Asia. Huabeisaurus comes from Kangdailiang and Houyu, Zhaojiagou Town, Tianzhen County, Shanxi province, China. The holotype was found in the unnamed upper member of the Huiquanpu Formation, which is Late Cretaceous (?Cenomanian–?Campanian) in age based on ostracods, charophytes, and fission-track dating.

Huabeisaurus measures 20 metres (66 ft) long and 5 metres (16 ft) high, as estimated by Pang and Cheng in 2000. It would have been a quadrupedal herbivore with a long neck and tail, like most other sauropods. The skeleton has been presumed to have belonged to an almost mature individual, because it lacks sutures on vertebrae, but not on pelvic material. A set of 12 characters were identified by D'Emic et al. in 2013 that differentiate Huabeisaurus from other sauropods.

An isolated humerus, designated the paratype by Pang and Cheng, comes from a locality over 200 meters away from the type locality of Huabeisaurus, in a fluvially deposited sandy conglomeratic layer in the lower member of the Huiquanpu Formation. This layer is roughly 90 m lower stratigraphically than the type horizon of Huabeisaurus, which comes from the upper member of the Huiquanpu Formation. The humerus thus comes from a stratum representing a different and likely older depositional environment than that of Huabeisaurus, and does not overlap anatomically with the holotypic skeleton, and so cannot currently be referred it.

The discoverers erected a new family for the genus, Huabeisauridae, although this family name is not widely used amongst paleontologists. Recently, the family was again proposed, this time by D'Emic et al. because Euhelopodidae, which Huabeisaurus has been assigned to most recently, might have to be split into smaller clades throughout Somphospondyli because of all the taxa assigned to it.

Pang and Cheng tentatively suggested that "Titanosaurus" falloti be referred to Huabeisaurus. One problem, however, is that the femora of Huabeisaurus and "T." falloti differ in the bevel of the distal end versus the long axis of the bone, so the two cannot represent the same genus.

Jeffrey A. Wilson

Jeffrey A. Wilson also known as "JAW" is a professor of geological sciences and assistant curator at the Museum of Paleontology at the University of Michigan.

His doctoral dissertation was on sauropod evolution and phylogeny, and he has continued this work in cladistic analysis and revision of the group (see e.g. Wilson and Sereno 1994, 1998, Wilson 2005b, and especially Wilson 2002). With Paul Sereno, he defined the clades Macronaria and Somphospondyli (Wilson & Sereno 1998).

Wilson was also involved in the discovery and description of Pabwehshi pakistanensis, the first discovery of decent (diagnostic) Cretaceous crocodylian fossil remains from the Indian subcontinent, in the discovery of Rajasaurus narmadensis, the most completely known theropod dinosaur from India and a member of the family Abelisauridae, description of a number of North African dinosaurs (theropods and sauropods) from Niger, and rediscriptions of the Cretaceous sauropods Titanosaurus colberti (as Isisaurus) and Nemegtosaurus (previously thought to be a diplodocoid, but now recognised as a titanosaur).

His younger brother, Dr. Gregory P. Wilson, studies Mesozoic mammals and is currently an assistant professor in the Department of Biology at the University of Washington, and adjunct curator of vertebrate paleontology at the Burke Museum of Natural History and Culture.

Malarguesaurus

Malarguesaurus is a genus of titanosauriform sauropod dinosaur from the Late Cretaceous of Mendoza Province, Argentina. Its fossils, consisting of tail vertebrae, chevrons, ribs, and limb bones, were found in the late Turonian-early Coniacian-age (~89 million years old) Portezuelo Formation of the Neuquén Group. The type species, described by González Riga et al. in 2008, is M. florenciae.

Phuwiangosaurus

Phuwiangosaurus (meaning "Phu Wiang lizard") is a genus of titanosauriform dinosaur from the Early Cretaceous (Valanginian-Hauterivian) Sao Khua Formation of Thailand. The type species, P. sirindhornae, was described by Martin, Buffetaut, and Suteethorn in 1994; it was named to honour Princess Maha Chakri Sirindhorn of Thailand, who was interested in the geology and palaeontology of Thailand.

It was a mid-sized sauropod, measuring 15–20 m in length.

Phuwiangosaurus was originally assigned to Titanosauria, but more recent studies have placed it in a more basal position within the Titanosauriformes. Phylogenetic analyses presented by D'Emic (2012), Mannion et al. (2013), and Mocho et al. (2014) resolve Phuwiangosaurus within the Euhelopodidae, alongside genera such as Euhelopus and Tangvayosaurus. Other analyses have failed to find support for such a grouping, including some finding it to be paraphyletic at the base of Somphospondyli.

Ruyangosaurus

Ruyangosaurus (Ruyang County lizard) is a genus of titanosauriform sauropod dinosaur recovered from the Early Cretaceous Haoling Formation of China. The type species is R. giganteus, described in 2009 by Lü Junchang et al. Along with Huanghetitan and Daxiatitan, Ruyangosaurus is among the largest dinosaurs discovered in Cretaceous Asia.

Saltasaurinae

Saltasaurinae is a subfamily of titanosaurian sauropods known from the late Cretaceous period of South America, India and Madagascar. They are considered to be the most derived of all sauropods.

Sauroposeidon

Sauroposeidon ( SOR-o-po-SY-dən; meaning "lizard earthquake god", after the Greek god Poseidon) is a genus of sauropod dinosaur known from several incomplete specimens including a bone bed and fossilized trackways that have been found in the American states of Oklahoma, Wyoming, and Texas. The fossils were found in rocks dating from near the end of the Early Cretaceous (Aptian–early Albian), a time when sauropod diversity in North America had greatly diminished. It was the last known North American sauropod prior to an absence of the group on the continent of roughly 40 million years that ended with the appearance of Alamosaurus during the Maastrichtian.

While the holotype remains were initially discovered in 1994, due to their unexpected age and unusual size they were initially misclassified as pieces of petrified wood. A more detailed analysis in 1999 revealed their true nature which resulted in a minor media frenzy, and formal publication of the find the following year.Paleoecological analysis indicates that Sauroposeidon lived on the shores of the Gulf of Mexico, in a river delta. Extrapolations based on the more completely known Brachiosaurus indicate that the head of Sauroposeidon could reach 18 m (59 ft) in height with its neck extended, which would make it the tallest known dinosaur. With an estimated length of up to 34 m (112 ft) and a mass of 50–60 t (55–66 short tons), it also ranks among the longest and heaviest. However, this animal may not be as closely related to Brachiosaurus as previously thought, so these estimates may be inaccurate.

While initially described as a brachiosaurid closely related to Brachiosaurus and Giraffatitan, the discovery of additional remains in the Cloverly Formation of Wyoming suggested that it was in fact more closely related to the titanosaurs, in the group Somphospondyli. Analysis of these remains and comparison with others from Texas supported this conclusion, and demonstrated that the more completely known sauropods from the Twin Mountains Formation (including a partial skull and fossil trackways) previously named Paluxysaurus jonesi also belonged to Sauroposeidon. It is the state dinosaur of Texas.

Sibirotitan

Sibirotitan ("Siberian titan") is a genus of somphospondyl sauropod from the Ilek Formation of Russia. The type and only species is S. astrosacralis.

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.

Tangvayosaurus

Tangvayosaurus (meaning "Tang Vay lizard") is a genus of sauropod dinosaur from the Aptian-Albian age Lower Cretaceous Grès Supérior Formation of Savannakhet, Laos. It was a basal somphospondylan, about 15 m long, and is known from the remains of two or three individuals.

Tendaguria

Tendaguria ( TEN-də-GEWR-ee-ə; meaning "the Tendaguru one") is a genus of herbivorous sauropod dinosaur from the Late Jurassic of Tanzania.

Titanosaurus

Titanosaurus (meaning 'titanic lizard' – named after the mythological Titans, deities of Ancient Greece) is a dubious genus of sauropod dinosaurs, first described by Lydekker in 1877. It is known from the Maastrichtian (Upper Cretaceous) Lameta Formation of India.

Triunfosaurus

Triunfosaurus (meaning "Triunfo Basin reptile") is a genus of somphospondylan sauropod dinosaur from the Early Cretaceous of Brazil. It contains a single species, T. leonardii, described by Carvalho et al. in 2017. As a genus, Triunfosaurus can be distinguished from all other titanosaurs by the unique proportions of its ischium. It was initially described as a basal titanosaur, making it the earliest basal titanosaur known; however, subsequent research questioned the identification of the taxon as a titanosaur, instead reassigning it to the Somphospondyli.

Yongjinglong

Yongjinglong is an extinct genus of herbivorous derived titanosaur sauropod dinosaur known from the Early Cretaceous of Lanzhou-Minhe Basin of Gansu Province, China. It contains a single species, Yongjinglong datangi.

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