Tethyshadros

Tethyshadros ("Tethyan hadrosauroid") is a genus of dwarf hadrosauroid dinosaur from Trieste, Italy. The type and only species is T. insularis.

Tethyshadros
Temporal range: Late Cretaceous, 70 Ma
Tethyshadros insularis
Holotype skeleton
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Ornithischia
Suborder: Ornithopoda
Clade: Hadrosauromorpha
Genus: Tethyshadros
Dalla Vecchia, 2009
Species:
T. insularis
Binomial name
Tethyshadros insularis
Dalla Vecchia, 2009

Discovery and naming

Tethyshadros insularis 1
Skull and neck of the holotype

The genus was named and described by Italian paleontologist Fabio Marco Dalla Vecchia in 2009. Its only and type species is Tethyshadros insularis. The genus name refers to the Tethys Ocean and the Hadrosauroidea. The specific name means "insular" or "of the island" in Latin, a reference to the location of the discovery of the type specimen on the Adriatic-Dinaric Island, one of the larger islands of the European Archipelago.[1]

Tethyshadros is based on holotype SC 57021, a mostly complete but crushed skeleton, that had previously been nicknamed "Antonio," as well as a few referred specimens. The growth lines of the bones indicate that the holotype was perhaps five to six years old.[1][2]

Tethyshadros NT
Restoration

"Antonio" was found at the Villaggio del Pescatore site in the Province of Trieste, near Duino-Aurisina. This site was discovered in the 1980s by Alceo Tarlao en Giorgio Rimoli in an old quarry near the sea. Here, layers are exposed from the Liburnia Formation, from the Campanian-Maastrichtian ages, which occurred 70-71 million years ago. In them a chalkstone lens was present, containing fossils and measuring ten metres thick and seventy metres in diameter. In 1994 student Tiziana Brazzatti discovered the hand bones of a larger skeleton. Stoneage, a company dealing in fossil collection, was commissioned to retrieve any remains, for which an overburden of three hundred tons had to be removed. Paleontologist Dalla Vecchia was later brought in to provide professional guidance. In April 1999 "Antonio" was removed from the quarry, being slightly damaged by the process.[1]

In December 2000 "Antonio" underwent a further 2800 hours of preparation. It was sprayed with formic acid to dissolve the chalk matrix and the gradually exposed bone was protected with resin. Another six specimens of Tethyshadros were discovered, one of them a skeleton that fell apart during the removal, another a skeleton of which only the forelimbs were recovered. All fossils are kept at the Civico Museo di Storia Naturale di Trieste but are property of the Italian State: "SC" stands for "State Collection."[1]

Description

Tethyshadros Scale
Size of Tethyshadros compared with a human

With a length of about 4 metres (13 ft) and a weight of 350 kilograms (770 lb), Tethyshadros is a relatively small species. Dalla Vecchia has hypothesized that this is an instance of insular dwarfism. The skull is relatively long, the neck and tail short. The legs, especially the shin bones, are long. These proportions, combined with a reduction of the number of fingers, are seen as cursorial adaptations for bipedal running.[1]

Tethyshadros shows a mix of basal and derived traits. A cladistic analysis indicates that it was closely related to the Hadrosauridae sensu Sereno and Telmatosaurus. According to Dalla Vecchia, the presence of Tethyshadros on a European island is caused by a radiation of basal hadrosauroids, island-hopping from Asia. He rejects the possibility that the species is a relict of isolated evolution from earlier European hadrosauroids or descended from American hadrosaurs.[1]

See also

References

  1. ^ a b c d e f Dalla Vecchia, F. M. (2009). "Tethyshadros insularis, a new hadrosauroid dinosaur (Ornithischia) from the Upper Cretaceous of Italy". Journal of Vertebrate Paleontology. 29 (4): 1100–1116. doi:10.1671/039.029.0428.
  2. ^ Cristiano Dal Sasso. (2005). Dinosaurs of Italy, Indiana University Press, p. 106
Ankylopollexia

Ankylopollexia is an extinct clade of ornithischian dinosaurs that lived from the Late Jurassic to the Late Cretaceous. It is a derived clade of iguanodontian ornithopods and contains the subgroup Styracosterna.

The name stems from the Greek word, “ankylos”, mistakenly taken to mean stiff, fused (in fact the adjective means bent or curved; used of fingers, it can mean hooked), and the Latin word, “pollex”, meaning thumb. Originally described in 1986 by Sereno, this most likely synapomorphic feature of a conical thumb spine defines the clade.First appearing around 156 million years ago, in the Jurassic, Ankylopollexia became an extremely successful and widespread clade during the Cretaceous, and were found around the world. The group died out at the end of the Maastrichtian. Even though they grew to be quite large, comparable to some carnivorous dinosaurs, they were universally herbivorous. Most ankylopollexians were bipedal.

Aralosaurini

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Batyrosaurus

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Civico Museo di Storia Naturale di Trieste

Civico Museo di Storia Naturale di Trieste is a natural history museum in Trieste, northern Italy. It contains several collections, including more than two millions botanical, zoological, mineralogical, geological, and paleontological specimens.

Elasmaria

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Gobihadros

Gobihadros is a genus of basal hadrosauroid dinosaur from the Late Cretaceous of Mongolia. It contains one species, Gobihadros mongoliensis. The holotype specimen was recovered from the Bayan Shireh Formation (Cenomanian-Santonian). Its length was estimated at just under 3 meters (10 feet) long.

Hadrosauroidea

Hadrosauroidea is a clade or superfamily of ornithischian dinosaurs that includes the "duck-billed" dinosaurs, or hadrosaurids, and all dinosaurs more closely related to them than to Iguanodon.They are from Asia, Europe and Africa. Many primitive hadrosauroids, such as the Asian Probactrosaurus and Altirhinus, have traditionally been included in a paraphyletic (unnatural grouping) "Iguanodontidae". With cladistic analysis, the traditional Iguanodontidae has been largely disbanded, and probably includes only Iguanodon and perhaps its closest relatives.

Hadrosauromorpha

Hadrosauromorpha is a cohort of iguanodontian ornithopods, defined in 2014 by David B. Norman to divide Hadrosauroidea into the basal taxa with compressed manual bones and a pollex, and the derived taxa that lack them. The clade is defined as all the taxa closer to Edmontosaurus regalis than Probactrosaurus gobiensis. This results in different taxon inclusion depending on the analysis.

Huehuecanauhtlus

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Huxleysaurus

Huxleysaurus (meaning "Huxley's lizard") is a genus of herbivorous styracosternan ornithopod dinosaur.

Iguanodontia

Iguanodontia (the iguanodonts) is a clade of herbivorous dinosaurs that lived from the Middle Jurassic to Late Cretaceous. Some members include Camptosaurus, Dryosaurus, Iguanodon, Tenontosaurus, and the hadrosaurids or "duck-billed dinosaurs". Iguanodontians were one of the first groups of dinosaurs to be found. They are among the best known of the dinosaurs, and were among the most diverse and widespread herbivorous dinosaur groups of the Cretaceous period.

Jaxartosaurus

Jaxartosaurus is a genus of hadrosaurid dinosaur similar to Corythosaurus which lived during the Late Cretaceous. Its fossils were found in Kazakhstan.

Laiyangosaurus

Laiyangosaurus ("Laiyang lizard") is a genus of saurolophine hadrosaurid from the Late Cretaceous of China. It is known from one species, L.youngi, found in the Laiyang Basin within the province of Shandong.

Lapampasaurus

Lapampasaurus is an extinct genus of hadrosaurid known from the Late Cretaceous Allen Formation (late Campanian or early Maastrichtian stage) of La Pampa Province, Argentina. It contains a single species, Lapampasaurus cholinoi.The generic name refers to the Argentine province of La Pampa. The specific name honours the late collector José Cholino. The material includes cervical, dorsal, sacral and caudal vertebrae, the forelimb girdle, and the partial hindlimb.

Plesiohadros

Plesiohadros is an extinct genus of hadrosauroid dinosaur. It is known from a partial skeleton including the skull collected at Alag Teg locality, from the Campanian Djadochta Formation of southern Mongolia. The type species is Plesiohadros djadokhtaensis.

Shantungosaurus

Shantungosaurus, meaning "Shandong Lizard", is a genus of saurolophine hadrosaurid dinosaurs found in the Late Cretaceous Wangshi Group of the Shandong Peninsula in China. The stratigraphic interval of Shantungosaurus ranges from the top of the Xingezhuang Formation to the middle of the Hongtuya Formation, middle to late Campanian in age. Shantungosaurus is so far the largest hadrosauroid taxon in the world: the greatest length of its femur is about 1.7 m, and the greatest length of its humerus is about 0.97 m.

Tsintaosaurini

Tsintaosaurini is a tribe of basal lambeosaurine hadrosaurs native to Eurasia. It currently contains only Tsintaosaurus (from China) and Pararhabdodon (from Spain ).Koutalisaurus, also known from late Cretaceous Spain and formerly referred to Pararhabdodon

, may also be a tsintaosaurin because of its association with the latter genus; some recent work also suggests it may indeed be referrable to Pararhabdodon.

Xuwulong

Xuwulong is a genus of hadrosauroid dinosaur from the Early Cretaceous period. It lived during the early Cretaceous period (Aptian-Albian age) in what is now Yujingzi Basin in the Jiuquan area, Gansu Province of northwestern China. It is known from the holotype – GSGM F00001, an articulated specimen including a complete cranium, almost complete axial skeleton, and complete left pelvic girdle from Xinminpu Group. Xuwulong was named by You Hailu, Li Daqing and Liu Weichang in 2011 and the type species is Xuwulong yueluni.

Zhanghenglong

Zhanghenglong is an extinct genus of herbivorous hadrosauroid iguanodont dinosaur known from the Late Cretaceous (middle Santonian stage) Majiacun Formation in Xixia County of Henan Province, China. It contains a single species, Zhanghenglong yangchengensis, represented by a disarticulated and partial cranium and postcranial skeleton.

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