''Gengasaurus'' is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

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 e ...

ichthyosaur Ichthyosauria is an order of large extinct marine reptiles sometimes referred to as "ichthyosaurs", although the term is also used for wider clades in which the order resides. Ichthyosaurians thrived during much of the Mesozoic era; based on fo ...

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 143.1 Mya. ...

. 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, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...

about 152 million years ago.

History

The near complete

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

was discovered in 1976 in the

Late Jurassic The Late Jurassic is the third Epoch (geology), epoch of the Jurassic Period, and it spans the geologic time scale, geologic time from 161.5 ± 1.0 to 143.1 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic stratum, strata.Owen ...

(

Tithonian In the geological timescale, the Tithonian is the latest age (geology), age of the Late Jurassic Epoch and the uppermost stage (stratigraphy), stage of the Upper Jurassic Series. It spans the time between 149.2 ±0.7 annum, Ma and 143.1 ±0.6 (mi ...

) Calcari ad aptici e Saccocoma Formation 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

{{Taxonbar, from=Q39050749 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