Aegirosaurus

Aegirosaurus is an extinct genus of platypterygiine ophthalmosaurid ichthyosaurs known from the late Jurassic and early Cretaceous of Europe. It was originally named as a species of "Ichthyosaurus".
Discovery and species.
Originally described by Wagner (1853) as a species of the genus "Ichthyosaurus" ("I. leptospondylus"), the species "Aegirosaurus leptospondylus" has had an unstable taxonomic history. It has been referred to the species "Ichthyosaurus trigonus posthumus" (later reclassified in the dubious genus "Macropterygius") in the past, and sometimes identified with "Brachypterygius extremus". In 2000, Bardet and Fernández selected a complete skeleton in a private collection as the neotype for the species "I. leptospondylus", as the only other described specimen was destroyed in World War II. A second specimen from the Munich collection was referred to the same taxon. Bardet and Fernández concluded that the neotype should be assigned to a new genus, "Aegirosaurus". The name means 'Aegir (teutonic god of the ocean) lizard with slender vertebrae'.
Within the Ophthalmosauridae, scientists once believed "Aegirosaurus" was most closely related to "Ophthalmosaurus". However, many recent cladistic analyses found it is more closely related to "Sveltonectes" (and probably to "Undorosaurus"). "Aegirosaurus" lineage was found to include "Brachypterygius" and "Maiaspondylus", too, and to nest within the Platypterygiinae, which is the sister taxon of Ophthalmosaurinae.
Stratigraphic range.
"Aegirosaurus" is known from the lower Tithonian (Upper Jurassic) of Bavaria, Germany. Its remains were discovered in the Solnhofen limestone formations, which have yielded numerous well-known fossils, such as "Archaeopteryx", "Compsognathus", and "Pterodactylus".
In addition to its late Jurassic occurrence, "Aegirosaurus" has recently been discovered from the late Valanginian (early Cretaceous) of southeastern France (Laux-Montaux, department of Drôme; Vocontian Basin), the first diagnostic ichthyosaur recorded from the Valanginian. This shows that most types of late Jurassic ichthyosaurs crossed the Jurassic-Cretaceous boundary.
Palaeobiology.
It was a small genus of ichthyosaur, with adults being less than in length. Tooth morphology and wear pattern suggest that "Aegirosaurus" belonged to the "Pierce II/ Generalist" feeding guild.