ИСТИНА

The ichthyosaur genus Nannopterygius from the Kimmeridge Clay Formation of England is among the most poorly known ichthyosaurs of the Late Jurassic. It was erected by Huene in 1922 to receive Ichthyosaurus enthekiodon Hulke, 1871, which is known from a single relatively complete, but poorly preserved skeleton. This was a moderately long (c. 3 m) ichthyosaur with slender rostrum and peculiar tiny forelimbs. The holotype and several fragmentary specimens of dubious affinity are the only material assigned to Nannopterygius. An additional issue is that the holotype is on display in the Natural History Museum, London, mounted high on the wall (c. 5 m) and under glass. To assess the holotype, I attached a camera with a polarizing filter to a fishing rod and connected it to a computer. The collected data reveals previously unknown morphological features of the pectoral girdle and forelimb. New observations on the holotype allowed to identify additional specimens of Nannopterygius in the collections of Natural History Museum and Oxford University Museum of Natural History. Apart from the overlapping elements, the newly identified specimens have representative cranial remains (including isolated elements of dermatocranium and basicranium) some of which either poorly known or unknown in the holotype. The new data increase our knowledge of Nannopterygius and allow the suggestion that two problematic Late Jurassic genera from Russia, Paraophthalmosaurus Arkhangelsky, 1997 and Yasykovia Efimov, 1999, are subjective junior synonyms of Nannopterygius, rather than of Ophthalmosaurus as was supposed by some previous researchers.