Ventastega was a basal tetrapod that lived during the Famennian subdivision of the Late Devonian period approximately 374.5 to 359.2 million years ago, though Ventastega origins as a tetrapod lineage are probably seated in the preceding Frasnian period of the Late Devonian (385.3 to 374.5 million years ago) when a surge of morphological diversification of tetrapods began. Ventastega is one of the earliest Devonian tetrapods yet discovered. Given two preferred orientations of the bones and the geological context in which Ventastega was found suggests a tidal-sea influence. However, like Tiktaalik, Ventastega was probably more aquatic than terrestrial. It had a relatively large size for its period, with a length up to 1 m (3.3 ft) and a 20 cm skull.

Per E. Ahlberg, a professor of evolutionary biology at Uppsala University in Sweden reported in Nature that limbs, not fins were attached to Ventastega; this inference is based on the anatomy of key parts of its pelvis and its shoulders. The fossils reported were found on the Kurzeme/Courland Peninsula in what is now western Latvia. They are 365 million years old. A skull, shoulders, and part of the pelvis of Ventastega curonica were found. They indicate it was more tetrapod than fish and looked similar to a small alligator. The discovery contributes to the understanding of the evolutionary transition from fish to tetrapods (animals with four limbs, whose descendents include amphibians, reptiles, dinosaurs and birds, and mammals).