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Somphospondyli
Temporal range:
Ma
Skeleton of Qiaowanlong
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Sauropodomorpha
Clade: Sauropoda
Clade: Macronaria
Clade:
Camarasauromorpha
Clade:
Titanosauriformes
Clade: Somphospondyli
Wilson & Sereno, 1998
Genera

Somphospondylans are an

sauropods that lived throughout the world from the Late Jurassic (Kimmeridgian) through the Late Cretaceous (Maastrichtian) in North America, South America, Europe, Asia, Africa and Australia. The group was first defined in 1998 by Jeffrey A. Wilson and Paul Sereno; uniting Euhelopus and Titanosauria.[1]

The name Somphospondyli is derived from the Greek "somphos" meaning spongy and "spondylos" meaning vertebra.[1] One of the most unique features of Somphospondylans is the spongy composition of the presacral vertebrae.[1] Being titanosauriforms, members of Somphospondyli were among the largest land-dwelling dinosaurs known to exist.

Classification

Somphospondylans were first defined by Wilson & Sereno (1998) as "the most inclusive clade that includes

Brachiosaurus altithorax". The group includes titanosauriform sauropods that are more similar to Saltasaurus than to Brachiosaurus.[1] Mannion et. al (2013) describes Somphospondyli as one of the two sister clades of Titanosauriformes, with the other being Brachiosauridae.[2]

Characteristics

Somphospondylans share the following

synapomorphies among tutanosauriforms:[1]

Additional features found as diagnostic of this clade by Mannion et al. (2013) include the possession of at least 15

caudal vertebrae; biconvex distal caudal vertebrae; humerus anterolateral corner "squared"; among multiple others.[2]

Cladistics

There exists some uncertainty in the classification of individual Somphospondylan sub-taxa.

Paluxysaurus were previously thought to be brachiosaurids, but later analyses have linked several of their synapomorphies to Somphospondyli.[5]

The following cladograms show Somphospondyli membership at increasing resolutions.

Wilson & Sereno (1998)

Adapted from Wilson & Sereno (1998), the cladogram below describes the relationships between Somphospondyli and its nearest relatives.[1]

Sauropodomorpha

Taylor (2009)

The following cladogram constructed from Taylor (2009) highlights Brachiosauridae and Somphospondyli, the branching constituent clades of Titanosauriformes.[6]

Elliott et. al. (2014)

Elliott et. al. (2014) derives a cladogram of Somphospondyli with a species-level resolution.[7]

Somphospondyli

Dongbeititan dongi

Euhelopodidae

Liubangosaurus hei

Gobititan shezhouensis

Tangvayosaurus hoffeti

Phuwiangosaurus sirindhornae

Qiaowanlong kangxii

Euhelopus zdanskyi

Erketu ellisoni

Astrophocaudia slaughteri

Brontomerus mcintoshi

Sonorasaurus thompsoni

Chubutisaurus insignis

Tastavinsaurus sanzii

Malarguesaurus florenciae

Sauroposeidon proteles

Paluxysaurus jonesi

Ligabuesaurus leanzai

"Cloverly titanosauriform"

Fukuititan nipponensis

Angolatitan adamastor

Wintonotitan wattsi

Ruyangosaurus giganteus

Huanghetitan liujiaxiaensis

"Huanghetitan" ruyangensis

Titanosauria

Andesaurus delgadoi

Xianshanosaurus shijiagouensis

Daxiatitan binglingi

Lithostrotia

Malawisaurus dixeyi

Rapetosaurus krausei

Mongolosaurus haplodon

Saltasauridae

Saltasaurus loricatus

Jiangshanosaurus lixianensis

Alamosaurus sanjuanensis

Dongyangosaurus sinensis

Opisthocoelicaudia skarzynskii

Diamantinasaurus matildae

Dongbeititan dongi is shown here to be the most basal member of Somphospondyli. This result is derived from the analysis in Mannion et. al. (2013) but is subject to variability in its position.[2]

Paleogeography

Somphospondylans were absent from Antarctica and Australasia during the Late Jurassic, although titanosauriformes were found in Africa, Europe, the Americas, and Pakistan at that time.[2] The Middle Jurassic Ardley tracksite in the UK provides evidence for an earlier origin of titanosaurs, or derived somphospondylans[8]. Somphospondylans became the dominant sauropods by the Cretaceous, reaching every continent with the exception of Antarctica.[2]

Some Somphospondylans are believed to have existed exclusively in inland environments.[9] This is a result of “wide-gauge”trackway remnants of Somphospondylans found to be indicative of terrestrial sauropods.

See also

References