Rare fossils expand evolutionary history of sperm whales
This skull belonged to an extinct species of pygmy sperm whale dubbed Nanokogia isthmia that once lived in an outer continental shelf habitat about 100 meters deep off the coast of Panama.
Velez-Juarbe et al. (CC-BY)
Long before Moby Dick scoured the seas for sailors, a pygmy sperm whale called Nanokogia isthmia scoured Panama’s coastal waters for lanternfish and squid.
Fossils from the previously unknown species were unearthed near a sea cliff on the Panamanian coast, researchers report April 29 in PLOS ONE. Sediments surrounding two well-preserved N. isthmia skulls date to around 7.5 million years ago.
Compared with modern specimens, the ancient pygmy sperm whale probably had a larger spermaceti organ, which helps sperm whales make noises and echolocate. Looking across the sperm whale family tree, the work also suggests that this organ shrunk twice in the animal’s evolutionary history. Sperm whale fossils are rare, and it’s unclear what may have driven the shrinkage.
