Pliosaurus irgisensis

Pliosaurus irgisensis (Novozhilov, 1948)

Holotype: PIN 426, partial skull, partial vertebral column, articulated pelvic paddle.
Stratum typicum: Savel’evsk oil shales, Tithonian (Volgian), Upper Jurassic.
Locus typicus: Savel-evsk Mine No. 1, eastern Saratov Province, Russia.
Diagnosis: Skull relatively short, its length not exceeding its width by more than three times; orbits small semicircular pits, separated by very narrow parietal bones; limbs narrow with very long fingers (from Knutsen 2010, after Novozhilov 1964 – warrants revision).
Current status: Nomen dubium.
Comments: The holotype specimen PIN 426 was discovered in 1933 during mining operations at Savel’evsk Mine No. 1, near Gorny, Russia (Storrs et al., 2000). It was originally displayed at the Pugachevsky Regional Museum in Pugachyov, Russia. Novozhilov (1948) first described the material as Peloneustes irgisensis. Later, Tarlo (1960) referred the species to Pliosaurus, though he noted being “unable either to accept or reject the validity of [Novozhilov’s] specific name” (Tarlo 1960, p. 174). Novozhilov (1948) established the new genus Strongylokrotaphus for the specimen, placing it within the Polycotylidae (Trinacromeriidae). Storrs et al. (2000) followed Tarlo (1960) in considering PIN 426 a species of Pliosaurus. Most recently, Benson et al. (2013, p. 4) concluded that diagnostic features for the taxon have yet to be established, suggesting it should be considered a nomen dubium referred to Thalassophonea indet.