''Gengasaurus'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

ophthalmosaurid Ophthalmosauridae is an extinct family of thunnosaur ichthyosaurs from the Middle Jurassic to the early Late Cretaceous (Bajocian - Cenomanian) worldwide. Almost all ichthyosaurs from the Middle Jurassic onwards belong to the family, until the ex ...

ichthyosaur Ichthyosaurs (Ancient Greek for "fish lizard" – and ) are large extinct marine reptiles. Ichthyosaurs belong to the order known as Ichthyosauria or Ichthyopterygia ('fish flippers' – a designation introduced by Sir Richard Owen in 1842, altho ...

from the

Jurassic The Jurassic ( ) is a Geological period, geologic period and System (stratigraphy), stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The J ...

. The type and only species, ''Gengasaurus nicosiai'', was named in 2017, after the locality of

Genga, Marche Genga is a town and ''comune'' of province of Ancona in the Italy, Italian region of the Marche, on the Sentino, Sentino river about downstream and east of Sassoferrato and north of Fabriano. The town is best known as the ancestral home of the n ...

. It lived in

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...

about 152 million years ago.

History

The near complete

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

was discovered in 1976 in the Late Jurassic (

Tithonian In the geological timescale, the Tithonian is the latest age of the Late Jurassic Epoch and the uppermost stage of the Upper Jurassic Series. It spans the time between 152.1 ± 4 Ma and 145.0 ± 4 Ma (million years ago). It is preceded by the K ...

)

Calcari ad aptici e Saccocoma Formation The Calcari ad aptici e Saccocoma Formation, also known as the Saccocoma Formation (known in English as the Haptic limestones and Saccocoma Formation), is a geologic formation in Camponocecchio, Italy that dates back to the Tithonian (152 Ma) - it ...

at Camponocecchio and it was described in 1980 and 2000 as the "Genga ichthyosaur" before it was named and described in 2016Ilaria Paparella, Erin E. Maxwell, Angelo Cipriani, Scilla Roncacè and Michael W. Caldwell (2016) - The first ophthalmosaurid ichthyosaur from the Upper Jurassic of the Umbrian–Marchean Apennines (Marche, Central Italy). ''Geological Magazine'' (advance online publication) - this paper was eventually published in 2017. The holotype is now housed at the Spaelaeo-Palaeontologic Museum in Genga.

Phylogeny

The following cladogram shows a possible phylogenetic position of ''Gengasaurus'' in Ophthalmosauridae according to the analysis performed by Zverkov and Jacobs (2020).

References

Ophthalmosaurinae Tithonian life Late Jurassic ichthyosaurs Ichthyosaurs of Europe Late Jurassic reptiles of Europe Jurassic Italy Fossils of Italy Fossil taxa described in 2017 Ichthyosauromorph genera {{Jurassic-reptile-stub