''Riabininohadros'' (meaning " Riabinin's

hadrosaur Hadrosaurids (), also hadrosaurs or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae. This group is known as the duck-billed dinosaurs for the flat duck-bill appearance of the bones in their snouts. The ornithopod fami ...

") is an extinct genus of

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 wo ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

from the

Maastrichtian The Maastrichtian ( ) is, in the International Commission on Stratigraphy (ICS) geologic timescale, the latest age (geology), age (uppermost stage (stratigraphy), stage) of the Late Cretaceous epoch (geology), Epoch or Upper Cretaceous series (s ...

Crimea Crimea ( ) is a peninsula in Eastern Europe, on the northern coast of the Black Sea, almost entirely surrounded by the Black Sea and the smaller Sea of Azov. The Isthmus of Perekop connects the peninsula to Kherson Oblast in mainland Ukrain ...

. Its type species is ''Riabininohadros weberi'', emended to ''Riabininohadros weberae''. It was originally classified as a species of ''

Orthomerus ''Orthomerus'' (meaning "straight femur") is a genus of dubious hadrosaurid dinosaur from the Late Cretaceous of the Netherlands. It is today an obscure genus, but in the past was conflated with the much better known ''Telmatosaurus''. Discover ...

'', until 2015.

Discovery and history

It was originally named ''Orthomerus weberi'' when first described by Anatoly Nikolaevich Riabinin in 1945 for hindlimb elements from an unnamed Maastrichtian-age formation in

of what is now Ukraine. These were in 1934 near

Bakhchysarai Bakhchysarai is a city in the Autonomous Republic of Crimea, Ukraine. It is the administrative center of the Bakhchysarai Raion (district), as well as the former capital of the Crimean Khanate. Its main landmark is Hansaray, the only extant ...

found by Gertruda Weber who is honoured in the specific name. The find was in 1937 reported in the scientific literature. As Weber was female, Lev Nesov in 1995 emended the name to ''Orthomerus weberae'' so the ending of the species name was also feminine. Although tossed as a ''nomen dubium'' in recent reviews of

Hadrosauridae Hadrosaurids (), also hadrosaurs or duck-billed dinosaurs, are members of the ornithischian family Hadrosauridae. This group is known as the duck-billed dinosaurs for the flat duck-bill appearance of the bones in their snouts. The ornithopod fam ...

,Weishampel, David B.; Horner, Jack R. (1990). "Hadrosauridae". In Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.). The Dinosauria (1st ed.). Berkeley: University of California Press. pp. 534–561. .Horner, John R.; Weishampel, David B.; Forster, Catherine A (2004). "Hadrosauridae". In Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.). The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 438–463. . it was informally given its own genus "Riabininohadros" by Russian amateur paleontologist Roman Ulansky. As this publication did not meet the requirements of the

International Code of Zoological Nomenclature The International Code of Zoological Nomenclature (ICZN) is a widely accepted Convention (norm), convention in zoology that rules the formal scientific name, scientific naming of organisms treated as animals. It is also informally known as the I ...

, "Riabininohadros" was not a valid name for the taxon until the name was formally published as new by Lopatin and Averianov in

2020 The year 2020 was heavily defined by the COVID-19 pandemic, which led to global Social impact of the COVID-19 pandemic, social and Economic impact of the COVID-19 pandemic, economic disruption, mass cancellations and postponements of even ...

. The holotype, specimen ZGTM 5751, was found alongside the remains of an unnamed member of

Styracosterna 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 ...

in an unnamed

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

(

)-aged marine deposit at Mt. Besh-Kosh in Crimea in a '' Belemnella casimirovensis'' ammonoid zone. It largely consists of a left hindlimb, including the thighbone, the shinbone, the calf bone, the astragalus, the calcaneus, the second and third metatarsal and the first phalanx of the second toe. In 2018, it transpired that Riabinin had misidentified several elements. Also a part of the right calf bone proved to be present. A postcranial juvenile skeleton in 1965 excavated at Aleshino, was considered to represent a different species, a hadrosaurid.Lopatin, A.V., Averianov, A.O., & Alifanov, V.R., (2018), "New Data on Dinosaurs of the Crimean Peninsula", ''Dokl. Biol. Sci.'', 482: 206–209

Classification

As ''

'' has typically been classified within or very close to

, ''Riabininohadros weberae'' was placed similarly by reviews of the family. However, as discussed by Lopatin and Averianov in 2020, the femur of ''Riabininohadros'' is very distinctive, and has no morphological equivalents within

Iguanodontia Ornithopoda () is a clade of ornithischian dinosaurs, called ornithopods (). They represent one of the most successful groups of herbivorous dinosaurs during the Cretaceous. The most primitive members of the group were bipedal and relatively sm ...

, the clade that includes hadrosaurs and their relatives. Instead, Lopatin and Averianov, in view of its basal astragalus, classified ''Riabininohadros'' as a primitive member of the

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 wo ...

, more specially the

, well outside

Hadrosauroidea Hadrosauroidea is a clade or superfamily of ornithischian dinosaurs that includes the "duck-billed" dinosaurs, or Hadrosauridae, and all dinosaurs more closely related to them than to ''Iguanodon''. Their remains have been recovered in Asia, Euro ...

, with uncertain relationships to other taxa in the clade.

References

External links

{{Taxonbar, from=Q19605699 Ankylopollexia Dinosaur genera Maastrichtian dinosaurs Fossil taxa described in 2020 Dinosaurs of Europe

Discovery and history

Classification

See also

References

External links