| Undorosaurus | |
|---|---|
)_%25D0%259C%25D1%2583%25D0%25B7%25D0%25B5%25D0%25B9_%25D0%25BF%25D0%25B0%25D0%25BB%25D0%25B5%25D0%25BE%25D0%25BD%25D1%2582%25D0%25BE%25D0%25BB%25D0%25BE%25D0%25B3%25D0%25B8%25D0%25B8._%25D0%25A3%25D0%25BD%25D0%25B4%25D0%25BE%25D1%2580%25D1%258B._%25D0%25A3%25D0%25BB%25D1%258C%25D1%258F%25D0%25BD%25D0%25BE%25D0%25B2%25D1%2581%25D0%25BA%25D0%25B0%25D1%258F_%25D0%25BE%25D0%25B1%25D0%25BB._%25D0%259D%25D0%25BE%25D1%258F%25D0%25B1%25D1%2580%25D1%258C_2013_-_panoramio.jpg) | |
| Recosntructed skeleton ofU. gorodischensis | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | †Ichthyosauria |
| Family: | †Ophthalmosauridae |
| Subfamily: | †Platypterygiinae |
| Genus: | †Undorosaurus Efimov,1999 |
| Type species | |
| †Undorosaurus gorodischensis (Efimov, 1999) | |
| Other species | |
| Synonyms | |
| |
Undorosaurus is anextinctgenus ofophthalmosauridichthyosaur known from westernRussia,Svalbard, andPoland.[1][4][2] It was a large ichthyosaur, with the type species measuring 4–6 metres (13–20 ft) long.[2]
Undorosaurus was named by Vladimir M. Efimov in1999 and thetype species isUndorosaurus gorodischensis. Thespecific name is named afterGorodischi [ru], thetype locality of this taxon.[4]U. trautscholdi is named in honor of the geologistHermann Trautschold who collected and made the first description of the fossils of theholotype of the species.[2]
Undorosaurus was first known from theholotypeUPM EP-II-20 (527), a partial three-dimensionally preservedskeleton which preserved partialskull. It was collected near theVolga river at Gorodischi from theEpivirgatites nikitini ammonoid zone, dating to theLate Jurassic.[4]
A second species,U. trautscholdi, was discovered in 1878 byHermann Trautschold[5] and wasdescribed by M.S. Arkhangelsky and N.G. Zverkov in2014 from a partial left forefin found in the locality ofMnyovniki (Mnevniki) [ru],Moscow Oblast.[2]
The holotype (specimen GMUL UŁ no. 3579-81) of the third species,U. kielanae, was discovered in theKcynia Formation of the Owadów-Brzezinki Quarry,Poland, and it was first described by Daniel Tyborowski in 2016 asCryopterygius kielanae.[3]C. kielanae was moved toUndorosaurus by Zverkov & Efimov (2019).[6]
Maisch and Matzke (2000) regardedUndorosaurus to be a species ofOphthalmosaurus.[7] However, Storrset al. 2000 rejected this synonymy based on the tooth morphology of the specimen.[8] Chris McGowan and Ryosuke Motani (2003) pointed out two noteworthy differences toOphthalmosaurus, an incompletely fused ischiopubis and a remarkably strong dentition, and consideredUndorosaurus to be a valid genus of ophthalmosaurid.[9]Undorosaurus's validity is now accepted by most authors, even by Maisch (2010) who originally proposed the synonymy.[10][11][12]
Zverkov & Efimov (2019) considered the genusCryopterygius to be ajunior synonym of the genusUndorosaurus. The authors considered the type species of the former genus,C. kristiansenae, to be synonymous withUndorosaurus gorodischensis; second species ofCryopterygius,C. kielanae, was tentatively maintained by the authors as a distinct species within the genusUndorosaurus.[6]
The following cladogram shows a possible phylogenetic position ofUndorosaurus in Ophthalmosauridae according to the analysis performed by Zverkov and Jacobs (2020).[13]
| Ophthalmosauria |
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Cryopterygius (meaning 'frozen fin' in Greek) is adubiousextinctgenus ofophthalmosauridichthyosaur known from theAgardhfjellet Formation ofNorway. One species was recognised:C. kristiansenae.[14]
The holotype, PMO 214.578, consists of a single, but largely complete specimen from the Slottsmøya Member of theAgardhfjellet Formation that was excavated between 2004 and 2012. Druckenmiller et al. (2012) subsequently named and describedC. kristiansenae on the basis of this specimen.[14] It has been suggested thatC. kristiansenae may also be synonymous withUndorosaurus.[15]
A second species,C. kielanae, was found in theKcynia Formation from the Late Jurassic ofPoland.[16] It has since been synonymised withUndorosaurus and was found to be a species ofUndorosaurus (U. kielanae).[6]
