Petrustitan

Petrustitan Temporal range: Maastrichtian, 71–66  Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Paralectotype and lectotype of Petrustitan
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Dinosauria
Clade:	Saurischia
Clade:	† Sauropodomorpha
Clade:	† Sauropoda
Clade:	† Macronaria
Clade:	† Titanosauria
Genus:	† Petrustitan Díez Díaz et al., 2025
Species:	†P. hungaricus
Binomial name
†Petrustitan hungaricus (von Huene, 1932) [originally Magyarosaurus hungaricus]

Petrustitan is a eutitanosaurian sauropod dinosaur from the Late Cretaceous (Maastrichtian) of Romania. The type and only species is P. hungaricus, originally assigned to the genus Magyarosaurus . ^[1]

History of discovery

In 1932, Friedrich von Huene erected the genus Magyarosaurus and assigned three species based on sauropod specimens recovered from the Sânpetru Formation: M. dacus (the type species), M. hungaricus and M. transsylvanicus. ^[2] However, subsequent analyses considered only M. dacus as a valid species of Magyarosaurus, with "M." transsylvanicus representing a chimera and partially a junior synonym of M. dacus, and with "M." hungaricus representing a distinct genus. ^{[3] [1]}

In 2025, Díez Díaz and colleagues reassigned "M." hungaricus to a new genus Petrustitan. The generic name is derived from Ancient Greek words πέτρα (pétra, "stone, rock"), referring to the origin of the holotype (rocky outcrops of the type locality, Sânpetru), and τιτάν (tītā́n, "giant"), which is often used when naming titanosaurian sauropods. Both the paralectotype (left tibia) and lectotype (left fibula) of P. hungaricus are catalogued under the same specimen number, NHMUK R.3853. Some material originally referred to this taxon were also given a separate genus name, Uriash . ^[1]

References

1. Díez Díaz, V.; Mannion, P. D.; Csiki-Sava, Z.; Upchurch, P. (2025). "Revision of Romanian sauropod dinosaurs reveals high titanosaur diversity and body-size disparity on the latest Cretaceous Haţeg Island, with implications for titanosaurian biogeography". Journal of Systematic Palaeontology. 23 (1). 2441516. doi:10.1080/14772019.2024.2441516.
2. von Huene, F. (1932). "Die fossile Reptil-Ordnung Saurischia, ihre Entwicklung und Geschichte." Mong. Geol. Pal., 4(1) pts. 1 and 2, viii +361 pp.
3. Stein, K.; Csiki, Z.; Curry Rogers, K.; Weishampel, D.B.; Redelstorff, R.; Carballidoa, J.L.; Sander, P.M. (2010). "Small body size and extreme cortical bone remodeling indicate phyletic dwarfism in Magyarosaurus dacus (Sauropoda: Titanosauria)". Proceedings of the National Academy of Sciences of the United States of America. 20. 107 (20): 9258–9263. Bibcode:2010PNAS..107.9258S. doi: 10.1073/pnas.1000781107 . PMC   2889090 . PMID   20435913.