''Pessopteryx'' is an extinct genus of

ichthyosaur Ichthyosauria is an order of large extinct marine reptiles sometimes referred to as "ichthyosaurs", although the term is also used for wider clades in which the order resides. Ichthyosaurians thrived during much of the Mesozoic era; based on fo ...

from the

Early Triassic The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between 251.9 Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic Series, which ...

(

Olenekian In the geologic timescale, the Olenekian is an age (geology), age in the Early Triassic epoch (geology), epoch; in chronostratigraphy, it is a stage (stratigraphy), stage in the Lower Triassic series (stratigraphy), series. It spans the time betw ...

) of

Svalbard Svalbard ( , ), previously known as Spitsbergen or Spitzbergen, is a Norway, Norwegian archipelago that lies at the convergence of the Arctic Ocean with the Atlantic Ocean. North of continental Europe, mainland Europe, it lies about midway be ...

Norway Norway, officially the Kingdom of Norway, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. The remote Arctic island of Jan Mayen and the archipelago of Svalbard also form part of the Kingdom of ...

. The genus originally contained four species, ''P. nisseri'', ''P. arctica'', ''P. pinguis'', and ''P. minor'', which were named in 1910 by

Carl Wiman Carl Johan Josef Ernst Wiman (March 10, 1867 – June 15, 1944) was a Swedish Palaeontology, palaeontologist, the first professor of palaeontology and historical geology at Uppsala University, and the father of Swedish vertebrate palaeontolo ...

. Only ''P. nisseri'' is still considered valid; ''P. arctica'' and ''P. pinguis'' are considered ''

nomina dubia 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 ...

'' while ''P. minor'' was reassigned to the tenuous genus ''

Isfjordosaurus ''Isfjordosaurus'' is an extinct genus of ichthyopterygian marine reptile that lived during the Early Triassic. Fossils have been found on the island of Spitsbergen, part of the Svalbard archipelago off the northern coast of Norway. It was forma ...

''. '' Omphalosaurus nisseri'', '' Merriamosaurus hulkei'', and ''Rotundopteryx hulkei'' are all

junior synonym In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The botanical and zoological codes of nomenclature treat the concept of synonymy differently. ...

s of ''P. nisseri''.

References

Early Triassic ichthyosaurs Early Triassic reptiles of Europe Fossils of Norway Fossil taxa described in 1910 Ichthyosauromorph genera {{ichthyosaur-stub