Myobradypterygius is an extinct genus of ophthalmosaurid ichthyosaur from the Early Cretaceous (Barremian-Hauterivian) of Argentina and possibly also Chile. One species is known, M. hauthali,Huene, F. von. (1927). Beitrag zur Kenntnis mariner mesozoischer Wirbeltiere in Argentinien. Centralblatt für Mineralogie, Geologie und Paläontologie, B 1927:22-29. which was once believed to have been a species of Platypterygius.McGowan, C. (1972). The systematics of Cretaceous ichthyosaurs with particuliar reference to the material from North America. Contributions to Geology. 1972;11:9–29.
Discovery and naming The holotype, MLP 79-I-30-2, a vertebral column and associated forelimbs, was discovered between 1900 and 1925 by Rudolph Hauthal at Nevado de Famatina, Argentina. The specimen was first described by von Huene (1925) and he reconstructed the forelimb, and described it as being related to Myopterygius (now Pervushovisaurus).Huene, F. von. (1925). Ichthyosaurier aus der Kreide Argentiniens. Revista del Museo de La Plata 28:234-238.
A second specimen, MLP 79-I-30-1, which included a left humerus and a forefin, was described by von Huene (1927) and in the same paper, both specimens were believed to belong to the same species, which was named Myobradypoterygius hauthali.
A second species, M. mollensis, was named by Carlos Rusconi (1938) on the basis of specimen MHN-PV 106, a set of vertebrae found in the Los Molles Formation of Argentina,C. Rusconi. (1938). Restos de ictiosaurios del Jurásico Superior de Mendoza [Remains of ichthyosaurs from the Upper Jurassic of Mendoza]. Boletin Paleontológico de Buenos Aires 10:1-4 but it has since been synonymised with Platypterygius and was not mentioned in the 2024 reappraisal of the genus.
McGowan (1972) synonymised M. hauthali with Platypterygius and created the new name Platypterygius hauthali.
Stinnesbeck et al. (2014) described around forty ichthyosaur specimens from the Zapata Formation of Chile, several of which had previously been assigned to Platypterygius, and assigned several of the specimens to what would later become Myobradyopterygius hauthali.
Fernández and Aguirre-Urreta (2005) reviewed the holotype and were the first to determine that it did not belong to Platypterygius. Campos et al. (2024) reinstated the genus Myobradyopterygius and confirmed it is separate from Platypterygius.
Description Myobradypterygius is thought to have been a small ichthyosaur, with an estimated total body length of .
Classification In 1925, Myobrachyopterygius was classified as being similar to Perushovisaurus. In 1972, it was allied with Platypterygius, and in 2024, Myobrachyopterygius was classified within Ophthalmosauridae.
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