Palvennia is an extinctgenus of ophthalmosauridichthyosaurian known from the uppermost Jurassic of Central Spitsbergen, Norway.[1][2] It was named for PalVenn, the Friends of the Palaeontological Museum in Oslo, whose expedition led to the discovery of the type specimen. Palvennia was a medium-sized ichthyosaur, measuring 3–4 m (9.8–13.1 ft) long.[3] It was originally known from a single skull from the Slottsmøya Member of the Agardhfjellet Formation (middle Volgian/late Tithonian, Late Jurassic) that measures 86 cm (2 ft 10 in) long. It is unusual in having a very short rostrum (~0.6× the skull length), similar to Ichthyosaurus breviceps. Because of this, the orbit seems very large (0.34× the skull length), but this may be effected by crushing. The single and only known species is Palvennia hoybergeti Druckenmiller et al., 2012.[1] A second specimen, which included both cranial and anterior postcranial material, was described in 2018.[4] In 2019, Palvennia was synonymized with Arthropterygius, though maintained as a separate species, by Nikolay Zverkov and Natalya Prilepskaya,[5] although this synonymy was objected to later that same year by Lene Delsett and colleagues, who maintained that they were sufficiently different to warrant separate genera.[6]
