Pinocetus

Pinocetus is an extinct genus of baleen whale (Mysticeti) that lived during the late Oligocene epoch, approximately 28 to 23 million years ago. Fossils of Pinocetus have been found in what is now Azerbaijan. This genus is significant in understanding the early evolution of baleen whales, particularly in the transition from toothed ancestors to the baleen-filtering feeding strategy.

Pinocetus is characterized by a combination of features, some of which are primitive and shared with archaeocetes (early whale ancestors), while others are more derived, pointing towards the development of modern baleen whales. Key characteristics include:

• Skull Morphology: The skull structure exhibits features indicative of the beginning stages of baleen development. While Pinocetus likely possessed teeth, the presence of nutrient foramina suggests the development of a vascular system associated with baleen plates.
• Mandible: The mandible, or lower jaw, shows characteristics related to the evolution of the baleen whale jaw structure.
• Vertebrae: The vertebral column possesses features that provide clues to the swimming style and overall body plan of this early whale.

The discovery and study of Pinocetus contributes to the understanding of the evolutionary lineage leading to modern baleen whales, shedding light on the origin and diversification of this major group of marine mammals. Further research and fossil discoveries are crucial to clarifying the precise relationships between Pinocetus and other early mysticetes.