Marmoretta
Marmoretta is an extinct genus of small lepidosauromorph reptile known from the Middle Jurassic (late Bathonian age) of Oxfordshire, England and Skye, Scotland. It contains a single species, Marmoretta oxoniensis. Etymology. "Marmoretta" was first described and named by Susan E. Evans in 1991 and the type species is "Marmoretta oxoniensis". The generic name is derived from Latin "marmoros", meaning "Marble" and refers to the Forest Marble Formation - the source of the initial specimens of "Marmoretta". The specific name is derived from "Oxonia", the Latinised form of "Oxford", in reference to Oxfordshire. Discovery. "Marmoretta" is known from holotype BMNH R.12020 , the anterior region of a right maxilla. Many specimens are referred to the species from the type locality, and together represent a nearly complete skull. All specimens are housed in the Natural History Museum. They were collected from the Mammal Bed of the Forest Marble Formation, at Kirtlington, Oxfordshire, which has yielded a rich assemblage of small vertebrates including mammals, frogs, salamanders and other small reptiles. "Marmoretta" is very common in that locality but its remains are fragmentary. In 1994, additional specimens of "Marmoretta" were described from the Kilmaluag Formation (previously known as the Ostracod Limestones) of the Great Estuarine  Group in Skye. This material of "Marmoretta" includes the first associated skull and postcranial remains. They confirm the original description and reconstruction, and provide additional support for position of "Marmoretta" as the sister taxon of Lepidosauria. Both localities dates to the Late Bathonian stage of the Middle Jurassic period, about 166.2-164.7 million years ago. In 2021, the Skye material was redescribed with CT scanning, and was found to slightly differ from the specimens from Oxford, with a different arrangement of palatal teeth and a differently shaped parabasisphenoid. Phylogeny. Susan E. Evans and Magdalena Borsuk−Białynicka (2009) performed a phylogenetic analysis  that recovered "Sophineta" as the sister group of Lepidosauria. The inclusion of "Sophineta" displaced the relictual Middle Jurassic "Marmoretta" and gave the origin of Lepidosauria much older age. The cladogram below follows their results. Some subsequent phylogenies have recovered "Marmoretta" as a stem-squamate, closer to squamates than rhynchocephalians. In the 2021 redescription, it was found to be a basal lepidosauromorph, most closely related to "Fraxinisaura" from the Middle Triassic of Germany.