Tambatitanis Temporal range: Early Cretaceous, Albian | |
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Caudal vertebrae of Tambatitanis | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | † Sauropodomorpha |
Clade: | † Sauropoda |
Clade: | † Macronaria |
Clade: | † Titanosauria |
Genus: | † Tambatitanis Saegusa & Ikeda, 2014 |
Type species | |
†Tambatitanis amicitiae Saegusa & Ikeda, 2014 |
Tambatitanis (meaning "Tamba giant", after Tamba, the name given to the northwest of Kansai, Japan [1] ) is an extinct genus of titanosauriform, possibly a titanosaurian, sauropod dinosaur from the Early Cretaceous (early Albian) aged Ohyamashimo Formation of the Sasayama Group. It is known from a single species, Tambatitanis amicitiae, known from a partial skeleton. [1]
The holotype specimen of the Tambaitanis, MNHAH D-1029280 was initially discovered in August 2006, by Shigeru Murakami and Kiyoshi Adachi in the reddish mudstone bed of the Ohyamashimo Formation (Lower Formation of the Sasayama Group) on a riverbed of the Sasayama RIver in Kamitaki, Sannan-Cho, Tamba-Sasayama city, of Hyōgo Prefecture, Japan. [2] It took five field seasons, from 2006 to 2010 to excavate a fossil because access to the skeleton was only available during the winter when the water level of the river becomes lowest. It was originally called 'Tamba-Ryu' before the publication in 2014. The specimen is somewhat semi-articulated and includes teeth, a braincase, a dentary, an atlas, a fragmental cervical vertebra, dorsal ribs, two fragmental dorsal vertebrae, a pubis, an ilium, sacral spines, presumable first sacral ribs, 22 caudal vertebrae, and 17 chevrons. [1]
In 2014, Haruo Saegusa and Tadahiro Ikeda described Tambatitanis amicitiae as a new genus and species of titanosauriform sauropod based on these remains. The generic name Tambatitanis is derived from the words, Tamba, the city where the fossil was discovered, with the Ancient Greek word "titanis", meaning titan. The specific name, amicitiae was derived from the Latin word "amicitia", referring to the friendship between 2 discoverers of this fossil. [1]
Phylogenetic analysis from Saegusa and Ikeda (2014) suggests Tambatitanis was Euhelopodidae, but its specific placement is uncertain among this group due to polytomy shown in the matrix, which is mainly based on D'Emic (2012). [3] In contrast, the describers of Ruixinia recovered this taxon within Titanosauria based on their phylogenetic analysis in 2023, the cladogram of which can be seen below: [4]
Tambatitanis is known from the Ohyamashimo Formation (Sasayama Group), which dates to the early–middle Albian age from the end of the Early Cretaceous. [5] These layers are predominantly made up by sandstones, mudstones, and conglomerates. The depositional environment represents a fluvial system with a subhumid to semi-arid climate. [6] Dinosaur teeth are common in various localities throughout this formation including those belonging to other theropods (dromaeosaurids, therizinosaurs, and tyrannosauroids) as well as sauropods, ankylosaurs, and iguanodontians. [7] Several dinosaurian oospecies (egg fossils) have also described, including Himeoolithus , Subtiliolithus , Nipponoolithus , and Prismatoolithus . [8] The monstersaurian lizard Morohasaurus and the troodontid theropod Hypnovenator [5] are known from the formation. [9] Fossils of an unnamed neoceratopsian, including several skull bones, are also known from the formation. [10] Although not specified as this Formation in original descriptions, Sasayama Group have some other fossil fauna known, such as eutherian Sasayamamylos , [11] scincomorph Pachygenys , [12] two frogs Hyogobatrachus and Tambabatrachus . [13]
Mongolosaurus is a genus of titanosauriform sauropod dinosaur which lived during the Early Cretaceous of China.
Pukyongosaurus is a genus of titanosauriform dinosaur that lived in South Korea during the Early Cretaceous period. It may have been closely related to Euhelopus, and is known from a series of vertebrae in the neck and back. The characteristics that were originally used to distinguish this genus have been criticized as being either widespread or too poorly preserved to evaluate, rendering the genus an indeterminate nomen dubium among titanosauriforms. The 2022 study noted that Pukyongosaurus is probably a somphospondylan.
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.
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.
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 upper Turonian-lower Coniacian Portezuelo Formation of the Neuquén Group. The type species, described by González Riga et al. in 2008, is M. florenciae.
Asioryctitheria is an extinct order of early eutherians.
The Kitadani Formation is a unit of Lower Cretaceous sedimentary rock which crops out near the city of Katsuyama in Fukui Prefecture, Japan, and it is the primary source of Cretaceous-aged non-marine vertebrate fossils in Japan. Dinosaur remains are among the fossils that have been recovered from the formation, but it also preserves a diverse assemblage of plants, invertebrates, and other vertebrates. Most, if not all, of the fossil specimens collected from the Kitadani Formation are reposited at the Fukui Prefectural Dinosaur Museum.
Wintonotitan is a genus of titanosauriform dinosaur from Cenomanian -age Winton Formation of Australia. It is known from partial postcranial remains.
The Kuwajima Formation is an Early Cretaceous geologic formation in Japan. Its precise age is uncertain due to a lack of identifying fossils, and it was previously considered likely Valanginian to Hauterivian in age. However, it is now considered to probably be Barremian in age. Dinosaurs and other vertebrates has been recovered from the Kaseki-kabe "Fossil-bluff" locality in the uppermost part of the formation.
The Okurodani Formation is an Early Cretaceous geologic formation in central Honshu, Japan. Part of the Tetori Group, it primarily consists of freshwater continental sediments deposited in a floodplain environment, with occasional volcanic tuffite horizons. It has an uncertain age, probably dating between the Hauterivian and Aptian. An indeterminate iguanodontian dinosaur tooth has been recovered from the formation. Many other fossil vertebrates are known from the KO2 locality
Monstersauria is a clade of anguimorph lizards, defined as all taxa more closely related to Heloderma than Varanus. It includes Heloderma, as well as several extinct genera, such as Estesia, Primaderma and Gobiderma, but this group was found to be polyphyletic in the most recent and complete squamate phylogenetic analysis by Reeder et al. (2015).
Rugocaudia is a potentially dubious genus of basal titanosauriform sauropod dinosaur known from the Early Cretaceous of Montana, United States.
Gobivenator is an extinct genus of troodontid theropod dinosaur known from the late Campanian Djadokhta Formation of central Gobi Desert, Mongolia. It contains a single species, Gobivenator mongoliensis. G. mongoliensis is known from a single individual, which represents the most complete specimen of a Late Cretaceous troodontid currently known.
Pachygenys is a genus of scincomorphan lizard from the Lower Cretaceous of Asia, P. thlastesa from the Doushan Formation, China, and P. adachii from the Ohyamashimo Formation, Japan. Its name is composed of the Greek words παχυς pachys ("thick") and γένυς génys ("jaw").
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Incognitoolithus is an oogenus of medioolithid fossil bird egg. It is notable for bearing evidence of predation, possibly from a bird pecking the eggshell.
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Hypnovenator is an extinct genus of troodontid theropod dinosaurs from the Early Cretaceous (Albian) Ohyamashimo Formation of Japan. The genus contains a single species, H. matsubaraetoheorum, known from a partial skeleton. Hypnovenator is the only troodontid currently known from Japan, and it represents the oldest definitive member of the subgroup Troodontinae.
The Ohyamashimo Formation(大山下層) is an Early Cretaceous (Albian) geologic formation in Japan. It has been dated to the early-mid Albian, between 112.1 ± 0.4 Ma and 106.4 ± 0.4 Ma. Dinosaur remains have been discovered from this formation, including the sauropod Tambatitanis and the theropod Hypnovenator. Other representative fossils from the formation include the monstersaurian lizard Morohasaurus and eutherian mammal Sasayamamylos. The depositional environment represents a fluvial system with a subhumid to semi-arid climate.