New ophthalmosaurids from Europe and Russia broaden the biodiversity of Early Cretaceous ichthyosaurs

Ophthalmosauridae is a successful clade of ichthyosaurs that rapidly diversified during the
Middle Jurassic. By Late Jurassic, Ophthalmosauridae were diverse, widespread, and formed
an important component of the marine trophic webs. By contrast, the record of Berriasian-
Aptian ichthyosaurs is extremely poor, and all ichthyosaurs from that interval have been
referred to a single genus, Platypterygius, until recently. This apparent diversity drop led
numerous authors to recognize a severe ichthyosaur extinction at the end of the Jurassic
that left ichthyosaurs as a small group on the decline. New specimens from poorly sampled
time periods (late Valanginian, late Hauterivian and late Barremian) in Europe and Russia
contradict this latest Jurassic extinction hypothesis and show that new and highly derived
as well as typically ‘Late Jurassic’ ichthyosaurs roamed the Eurasian archipelago during the
Early Cretaceous. Moreover, these new forms occupied ecological niches markedly different
from that of Platypterygius, significantly broadening the disparity and ecological diversity of
Cretaceous ichthyosaurs