Sibirotitan

Last updated

Sibirotitan
Temporal range: Early Cretaceous, Barremian
Ꞓ
O
S
D
C
P
T
J
K
Pg
N
↓
Sibirotitan metatarsal.png
Sibirotitan astrosacralis metatarsal I, PM TGU 16/0−8, in multiple views
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade:† Sauropodomorpha
Clade:† Sauropoda
Clade:† Macronaria
Clade:† Somphospondyli
Genus:† Sibirotitan
Averianov et al., 2017
Type species
Sibirotitan astrosacralis
Averianov et al., 2017

Sibirotitan ("Siberian titan") is a genus of somphospondyl sauropod from the Ilek Formation of Russia. The type and only species is S. astrosacralis. [1]

Contents

Discovery and naming

Sacrum on display in Tomsk State University Sibirotitan astrosacralis.jpg
Sacrum on display in Tomsk State University

The material assigned to Sibirotitan was found in the Shestakovo 1 locality of the Ilek Formation, deposited in a cliff on the Kiya River's right bank, near Shestakovo Village in Kemerovo Province, West Siberia, Russia. Vertebrate remains were first recovered in 1953, and larger dinosaur fossils were found later in the sixties. Definitive sauropod remains were first discovered during expeditions in 1994 and 1995. [1] In 2002, a reasonably complete foot would be described by Russian vertebrate paleontologist Alexander Averianov and colleagues; there was insufficient material to name the taxon, but they identified it as a member of Titanosauriformes, noting teeth from the locality indicated possible brachiosaur identity, but that a caudal vertebra from a nearby locality indicated the presence of a titanosaur as well. [2]

Model Sibirotitan model.jpg
Model

Specimens would continue to turn up, and in 2017, Averianov et al. would name those which could be confidently referred to as the same taxon as S. astrosacralis; this included teeth, a sacrum, assorted vertebrae, and the previously described foot. This made it the second sauropod species named from the country, after Tengrisaurus , named earlier in the same year; the genus Arkharavia , named in 2010, although originally described as a sauropod, was later reassigned to Hadrosauridae. [1] Earlier, in 2015, it had been informally nicknamed "Sibirosaurus" in the press. [3] [4] The final name of Sibirotitan was derived from Siberia, where it was found, and the Greek Τιτάν (titan), the second group of divine beings in Greek Mythology, preceding the Olympians. The specific name S. astrosacralis is derived from the Greek ἄστρον, meaning "star", and Latin os sacrum, meaning "sacred bone". This refers to the star-like way in which the sacral ribs radiate in dorsal view. [1]

The authors noted that Sibirotitan was one of the oldest titanosauriform species discovered in Asia. [1] More primitive known species were found in other parts of the world, such as Europe, North America, or Gondwana. Sibirotitan, alongside Fukuititan , are the first to appear in the Asian fossil record, both thought to have lived in the Barremian age. Later relatives are well known from Asia afterwards, from the Aptian through to the Santonian, and it is proposed that one of these later taxa could have given rise to the Lithostrotia, a titanosaur group whose earliest representatives are Asian genera such as Tengrisaurus (from the Barremian or Aptian of Russia) and Jiangshanosaurus (from the Albian of China). The latter was noted to have similar dorsal vertebrae to the much older Sibirotitan. [1]

Most of the referred specimens, although dis-articulated, are thought to have belonged to a single individual; it was suggested the large remains found in the 1960s could have originally been from the same skeleton as later remains, some found as recently as 2011. A singular cervical centrum was noted to be juvenile, and from a different individual, as the rest of the remains belonged to an adult animal. Among these fossils, PM TGU 120/10-Sh1-22, a dorsal vertebra, was selected as the holotype specimen. [1]

An axis vertebra from the type locality was later assigned to Sibirotitan astrosacralis as well. [5]

Description

Two characters were found to distinguish it from its close relatives. The hyposphene ridge on its dorsal vertebrae was particularly high, unlike other members of Titanosauriformes; this is the only autapomorphy of the taxon. Its possession of only five sacral vertebrae distinguishes it from all other somphospondyls, as possession of six is a synapomorphy of the clade. It was noted that juveniles have fewer vertebrae, but given the adult age of the individual examined, the trait was instead seen as an evolutionary reversal. [1]

Using one of the cervical vertebrae, a size estimate was attempted. They found it roughly corresponded in size to that of the diplodocoid sauropod Apatosaurus , and suggested a similar size of 20 tonnes might have been possible. [1]

Classification

Several characters were noted among the remains, four of which allowed classification in the group Titanosauriformes. These include the fashion in which the tooth crowns align in the jaw, presacral bone texture, and both the elongation of and the concave nature of certain parts of the cervical centra. An additional character, relating to the size of the arch of the cervical vertebrae, was used to assign it more specifically as a member of Somphospondyli. Characters in its vertebrae and ribs were found shared with Epachthosaurus and Euhelopus . [1]

A phylogenetic analysis was performed. It was noted that many differing and conflicting matrices exist for analyzing the systematics of Titanosauriformes, due to many taxa being poorly known. Because it is suited well for basal Titanosauriformes in particular, the matrix of Mannion et al. (2013) was chosen. In this analysis, it was found to be a relatively advanced non-titanosaurian somphosondyl. The following phylogenetic tree was produced: [1]

Somphospondyli

Related Research Articles

<i>Euhelopus</i> Extinct genus of dinosaurs

Euhelopus is a genus of sauropod dinosaur that lived between 145 and 133 million years ago during the Berriasian and Valanginian stages of the Early Cretaceous in what is now Shandong Province in China. It was a large quadrupedal herbivore. Like sauropods such as brachiosaurs and titanosaurs, Euhelopus had longer forelegs than hind legs. This discovery was paleontologically significant because it represented the first dinosaur scientifically investigated from China: seen in 1913, rediscovered in 1922, and excavated in 1923 and studied by T'an during the same year. Unlike most sauropod specimens, it has a relatively complete skull.

<i>Huabeisaurus</i> Extinct genus of dinosaurs

Huabeisaurus was a genus of dinosaur from the Late Cretaceous. 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.

<i>Mongolosaurus</i> Extinct genus of dinosaurs

Mongolosaurus is a genus of titanosauriform sauropod dinosaur which lived during the Early Cretaceous of China.

<i>Phuwiangosaurus</i> Extinct genus of dinosaurs

Phuwiangosaurus is a genus of titanosaur 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 a 1993 press release and was formally named in 1994. The species was named to honor Princess Maha Chakri Sirindhorn of Thailand, who was interested in the geology and palaeontology of Thailand, while the genus was named after the Phu Wiang area, where the fossil was discovered. The precise affinities of Phuwiangosaurus among titanosauriform sauropods are uncertain, though several studies have classified it as a euhelopodid.

<i>Huanghetitan</i> Extinct genus of dinosaurs

Huanghetitan, is a genus of sauropod dinosaur from the early Cretaceous Period. It was a basal titanosauriform which lived in what is now Gansu, China.

<i>Australodocus</i> Extinct genus of dinosaurs

Australodocus is a genus of sauropod dinosaur that lived during the Late Jurassic period, around 150 million years ago, in what is now Lindi Region, Tanzania. Though initially considered a diplodocid, recent analyses suggest it may instead be a titanosauriform.

Demandasaurus is a genus of rebbachisaurid sauropod dinosaur from early Cretaceous deposits of Spain. Demandasaurus is known from an incomplete but associated skeleton that includes cranial and postcranial remains. It was collected from the Castrillo de la Reina Formation in Burgos Province of Spain. It was first named by Fidel Torcida Fernández-Baldor, José Ignacio Canudo, Pedro Huerta, Diego Montero, Xabier Pereda Suberbiola and Leonardo Salgado in 2011 and the type species is Demandasaurus darwini.

<i>Overosaurus</i> Extinct genus of dinosaurs

Overosaurus is an extinct genus of sauropod dinosaurs, containing only a single species, Overosaurus paradasorum. This species lived approximately 86 to 84 million years ago during the latter part of the Cretaceous Period in what is now Patagonia. Overosaurus paradasorum was relatively small compared to other sauropods from Patagonia, like the saltasaurids and other aeolosaurines, estimated as approximately 10 m (33 ft). It was a ground-dwelling herbivore.

<i>Yongjinglong</i> Extinct genus of dinosaurs

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

The Ilek Formation is a Lower Cretaceous geologic formation in Western Siberia. Many different fossils have been recovered from the formation. It overlies the Late Jurassic Tyazhin Formation and underlies the Albian Kiya Formation.

<i>Padillasaurus</i> Extinct genus of reptiles

Padillasaurus is an extinct genus of titanosauriform sauropod known from the Early Cretaceous Paja Formation in Colombia. It contains a single species, Padillasaurus leivaensis, known only from a single partial axial skeleton. Initially described as a brachiosaurid, it was considered to be the first South American brachiosaurid ever discovered and named. Before its discovery, the only known brachiosaurid material on the continent was very fragmentary and from the Jurassic period. However, a more recent study finds it to be a basal somphospondylan.

Lohuecotitan is an extinct genus of titanosaurian sauropod dinosaur which lived during the Late Cretaceous in Spain. The only species known in the genus is Lohuecotitan pandafilandi, described and named in 2016.

<i>Savannasaurus</i> Extinct genus of dinosaurs

Savannasaurus is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Winton Formation of Queensland, Australia. It contains one species, Savannasaurus elliottorum, named in 2016 by Stephen Poropat and colleagues. The holotype and only known specimen, originally nicknamed "Wade", is the most complete specimen of an Australian sauropod, and is held at the Australian Age of Dinosaurs museum. Dinosaurs known from contemporary rocks include its close relative Diamantinasaurus and the theropod Australovenator; associated teeth suggest that Australovenator may have fed on the holotype specimen.

Tengrisaurus is a genus of lithostrotian sauropod, from the Early Cretaceous (Valanginian-Hauterivian) Murtoi Formation, Russia. It was described in 2017 by Averianov & Skutschas. The type species is T. starkovi. New remains were described in 2021 by Averianov, Sizov & Skutschas.

<i>Evgenavis</i> Extinct genus of dinosaurs

Evgenavis is a genus of pygostylian dinosaurs that lived from the Barremian to the Aptian. The type specimen ZIN PH 1/154 is an isolated tarsometatarsus found in the Ilek Formation, Western Siberia. Evgenavis may have been the only confuciusornithiform known outside the Jehol Biota, although there is also the possibility that it could have been a different type of avialan, such as an enantiornithean or a relative of Vorona. A cladogram within a 2019 study involving a wide range of theropods included Evgenavis as a longipterygid.

<i>Dzharatitanis</i> Extinct genus of dinosaurs

Dzharatitanis is a genus of sauropod from the Bissekty Formation in Uzbekistan, dating to the Turonian age of the Late Cretaceous. The genus contains a single species, Dzharatitanis kingi, named after geologist Christopher King, who contributed to the Cretaceous geology of Asia. It is currently one of two known sauropods from the Bissekty Formation, alongside an indeterminate titanosaur. In its original publication it was considered to be a member of Rebbachisauridae, but later papers considered it to be a titanosaur.

Fossiomanus is an extinct genus of tritylodontid mammaliamorphs from the Early Cretaceous of China. It includes one species, F. sinensis, which is known from a single nearly complete skeleton from the Aptian Jiufotang Formation. Features of its limbs and vertebrae indicate that Fossiomanus was adapted towards a fossorial lifestyle.

Ruixinia is an extinct genus of somphospondylan titanosauriform dinosaur from the Early Cretaceous (Barremian) Yixian Formation of China. The genus contains a single species, Ruixinia zhangi. The Ruixinia holotype is a partial articulated skeleton with the most complete series of caudal vertebrae known from any Asian titanosauriform.

<i>Garumbatitan</i> Genus of somphospondylan sauropod dinosaurs

Garumbatitan is an extinct genus of somphospondylan sauropod dinosaur from the Cretaceous Arcillas de Morella Formation of Spain. The genus contains a single species, G. morellensis, known from multiple partial skeletons.

<i>Kiyacursor</i> Genus of theropod dinosaurs

Kiyacursor is an extinct genus of noasaurid theropod dinosaur from the Early Cretaceous Ilek Formation of Russia. The genus contains a single species, K. longipes, known from a partial skeleton. Kiyacursor represents the first Early Cretaceous ceratosaur discovered in Asia, as well as the second non-avian theropod named from Russia, after Kileskus in 2010.

References

  1. 1 2 3 4 5 6 7 8 9 10 11 Averianov, A.; Ivanstov, S.; Skutschas, P.; Faingertz, A.; Leschinskiy, S. (2018). "A new sauropod dinosaur from the Lower Cretaceous Ilek Formation, Western Siberia, Russia". Geobios. 51: 1–14. doi:10.1016/J.GEOBIOS.2017.12.004.
  2. ↑ Alexander O. Averianov, Alexei V. Voronkevich, Evgeny N. Maschenko, Sergei V. Leshchinsky, Alexei V. Fayngertz (2002). "A sauropod foot from the Early Cretaceous of Western Siberia, Russia". Acta Palaeontologica Polonica. 47 (1): 117–124.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  3. ↑ Liesowska, Anna (27 March 2015). "Hello to the Sibirosaurus? New dinosaur discovered by university scientists". The Siberian Times.
  4. ↑ "Scientists discover Sibirosaurus - the latest dinosaur to have roamed the earth". The Herald. 28 March 2015.
  5. ↑ Averianov, A. O.; Lopatin, A. V. (2022-09-23). "New data on Sibirotitan, a titanosauriform sauropod from the Early Cretaceous of Western Siberia". Doklady Earth Sciences. 506 (1): 650–653. doi:10.1134/S1028334X22700040. ISSN   1028-334X. S2CID   252442250.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.