''Ponerosteus'' is a dubious

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

archosauromorph Archosauromorpha (Greek for "ruling lizard forms") is a clade of diapsid reptiles containing all reptiles more closely related to archosaurs (such as crocodilians and dinosaurs, including birds) rather than lepidosaurs (such as tuataras, liza ...

which was first identified as "

Iguanodon ''Iguanodon'' ( ; meaning 'iguana-tooth'), named in 1825, is a genus of iguanodontian dinosaur. While many species have been classified in the genus ''Iguanodon'', dating from the late Jurassic Period to the early Cretaceous Period of Asia, Eu ...

exogirarum" by

Antonín Frič Antonín Jan Frič (in German: Anton Johann Fritsch, 30 June 1832 – 15 November 1913) was a Czech paleontologist, biologist and geologist, living during the Austria-Hungary era. Professor at the Charles University and later became director of th ...

in 1878 for a specimen from the

Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...

(

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger 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 ''creta'', the ...

of the

Czech Republic The Czech Republic, or simply Czechia, is a landlocked country in Central Europe. Historically known as Bohemia, it is bordered by Austria to the south, Germany to the west, Poland to the northeast, and Slovakia to the southeast. The ...

, near Holubice by

Kralupy nad Vltavou Kralupy nad Vltavou (; german: Kralup an der Moldau) is a town in Mělník District in the Central Bohemian Region of the Czech Republic. It has about 18,000 inhabitants. It is known as a traffic hub and industrial agglomeration. The town is a part ...

;

Korycanar Formation The Korycanar Formation is a Late Cretaceous geologic formation in the Czech Republic.Weishampel, et al. (2004), pp. 582. Archosauromorph remains diagnostic to the genus level are among the fossils that have been recovered from the formationWe ...

). He later (1905) renamed it '' Procerosaurus'', unaware that this name was already in use ( von Huene, 1902). It was renamed ''Ponerosteus exogyrarum'' (species name amended) by George Olshevsky in 2000; however, the

taxon In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...

is considered a ''

nomen dubium In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium'' it may be impossible to determine whether a s ...

'' by most, as the type material is extremely poor, being apparently an internal cast of a

tibia The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it connects ...

from an animal that may or may not be a

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

. The name ''Ponerosteus'' can be translated as "bad", "worthless", or "useless bone", which accurately describes the nature of the material.George Olshevsky expands on the history of the taxon
on the Dinosaur Mailing List

References

Prehistoric animals of Europe Nomina dubia Fossil taxa described in 2000 Taxa named by George Olshevsky {{paleo-archosaur-stub