Similar finds in the related "Stenopterygius" also show this. Otto Jaekel in 1904 reassigned it to its own genus, "Stenopterygius". Beautifully preserved fossils of "Stenopterygius" have been found in Germany. In one female of "Stenopterygius" seven have been identified, in another eleven. The type species is therefore "Stenopterygius quadriscissus". The habits of "Stenopterygius" spp. were similar to those of present-day dolphins. In 2018, evidence of blubber was discovered with "Stenopterygius". A new Middle Jurassic species from southwestern Germany, "Stenopterygius aaleniensis", was described in 2012. "Stenopterygius" was originally named by Quenstedt in 1856 as a species of "Ichthyosaurus", "I. quadriscissus".