Deep inside a limestone cave in western Cuba, paleontologists have found the most complete ichthyosaur skeleton yet found on the island.
Ophthalmosaurid ichthyosaurs. Image credit: Dmitry Bogdanov / CC BY 3.0.
The ichthyosaur skeleton was discovered in 2023 in a fluvial cave in El Cuajaní, within the Viñales Geopark and National Park in western Cuba.
The exposed segment of the skeleton includes the U-shaped curved vertebral column with associated ribs, isolated vertebrae, and a single hindlimb.
“The specimen is preserved in the rock slab that forms the ceiling of the fluvial cave now known as Cueva del Ictiosaurio, at approximately 60 m from its entrance,” said Dr. Manuel Iturralde-Vinent from the Academia de Ciencias de Cuba and his colleagues from Cuba, Argentina, Poland and the United States.
The fossil dates back roughly 145 million years ago to the Tithonian age of the Late Jurassic epoch.
Until now, Cuba’s ichthyosaur record was largely confined to older, Oxfordian deposits.
“This fossil represents the most complete ichthyosaur recovered from Cuba to date,” the paleontologists said.
“It extends the temporal record of ichthyosaurs on the island, which previously only included specimens from the Oxfordian.”
The partial skeleton of the El Cuajaní ichthyosaur. Image credit: Iturralde-Vinent et al., doi: 10.1080/02724634.2025.2609717.
Though the El Cuajaní ichthyosaur, as the researchers informally call it, cannot yet be assigned to a specific species, its anatomy suggests affinities with a family of ichthyosaurs called Ophthalmosauridae.
“Its hindlimb morphology is comparable to that of Tithonian platypterygiine ophthalmosaurids, resembling Caypullisaurus bonapartei and Aegirosaurus leptospondylus,” they explained.
According to the scientists, the animal lived in a deep, open-marine within the early Caribbean seaway, a key marine corridor connecting distant parts of the Jurassic world.
“The Caribbean seaway became an important marine corridor since the mid Oxfordian, connecting the Eastern and Western Tethys, playing a pivotal role in the marine faunal dispersal since the Late Jurassic between Europe, the Gulf of Mexico, and the Pacific,” they said.
“This corridor had a latest Triassic-Early Jurassic ancestry represented by intercontinental rift valleys which should not be considered part of the early Caribbean basin or the Gulf of Mexico per se, but were precursors located in west-central Pangea.”
“The El Cuajaní ichthyosaur adds to the growing body of Tithonian ichthyosaur recently discovered in the region and could contribute to a better understanding of the biogeographic history of the group,” they concluded.
Their paper was published on February 6 in the Journal of Vertebrate Paleontology.
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Manuel Iturralde-Vinent et al. A partial ichthyosaur (?Ophthalmosauridae) skeleton from the Tithonian (Upper Jurassic) of western Cuba. Journal of Vertebrate Paleontology, published online February 6, 2026; doi: 10.1080/02724634.2025.2609717
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