Gengasaurus

Gengasaurus is an extinct genus of ophthalmosaurid ichthyosaur from the Jurassic. The type and only species, Gengasaurus nicosiai, was named in 2017, after the locality of Genga, Marche.^[1] It lived in Italy about 152 million years ago.^[2]

Gengasaurus Temporal range: Late Jurassic, 152 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	†Ichthyosauria
Family:	†Ophthalmosauridae
Subfamily:	†Ophthalmosaurinae
Genus:	†Gengasaurus Parapella et al., 2017
Species:	†G. nicosiai
Binomial name
†Gengasaurus nicosiai Parapella et al., 2017

History

The near complete holotype was discovered in 1976 in the Late Jurassic (Tithonian) Calcari ad aptici e Saccocoma Formation at Camponocecchio and it was described in 1980^[3] and 2000^[4] as the "Genga ichthyosaur" before it was named and described in 2016^[5][2] - this paper was eventually published in 2017.^[1] 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).^[6]

Ophthalmosauria

Ophthalmosaurinae Acamptonectes densus Mollesaurus periallus Ophthalmosaurus natans Ophthalmosaurus icenicus Gengasaurus nicosiai Nannopterygius yasykovi Nannopterygius enthekiodon Nannopterygius saveljeviensis Nannopterygius borealis Arthropterygius volgensis Arthropterygius lundi Arthropterygius thalassonotus Arthropterygius hoybergeti Arthropterygius chrisorum Platypterygiinae Brachypterygius extremus Aegirosaurus leptospondylus Muiscasaurus catheti Leninia stellans Sveltonectes insolitus Athabascasaurus bitumineus Platypterygius americanus Acuetzpalin carranzai Platypterygius sachicarum Caypullisaurus bonapartei Grendelius mordax Grendelius alekseevi Grendelius pseudoscythicus Grendelius zhuravlevi Undorosaurus kielanae Undorosaurus nessovi Undorosaurus gorodischensis Platypterygius australis Plutoniosaurus bedengensis Simbirskiasaurus birjukovi Platypterygius hercynicus Sisteronia seeleyi Platypterygius platydactylus Maiaspondylus lindoei

References

1. Ilaria Paparella; Erin E. Maxwell; Angelo Cipriani; Scilla Roncacè; Michael W. Caldwell (2017). "The first ophthalmosaurid ichthyosaur from the Upper Jurassic of the Umbrian–Marchean Apennines (Marche, Central Italy)". Geological Magazine. 154 (4): 837–858. Bibcode:2017GeoM..154..837P. doi:10.1017/S0016756816000455. S2CID 132955874.
2. "Paleo Profile: The Genga Lizard". Scientific American. Retrieved 9 October 2020.
3. Fastelli, C. & Nicosia, U. (1980). L'Ittiosauro di Genga (Ancona). In I vertebrati fossili italiani (eds Parisi, G. & Seppi, G.), pp. 95–101. Verona: Catalogo della Mostra.
4. De Marinis, G. & Nicosia, U. (2000). L'Ittiosauro di Genga. Castelferretti, Ancona: Cassa di Risparmio di Fabriano e Cupramontana Edizioni, 220 pp.
5. Ilaria 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)
6. Nikolay G. Zverkov & Megan L. Jacobs (2021) [2020]. "Revision of Nannopterygius (Ichthyosauria: Ophthalmosauridae): reappraisal of the 'inaccessible' holotype resolves a taxonomic tangle and reveals an obscure ophthalmosaurid lineage with a wide distribution". Zoological Journal of the Linnean Society. 191 (1): 228–275. doi:10.1093/zoolinnean/zlaa028.