Balaenoptera davidsonii

Balaenoptera davidsonii is an extinct rorqual of the genus Balaenoptera, native to the Pliocene San Diego Formation of California in the United States. Like Balaenoptera cephalus, it was originally classified under Eschrichtius, the gray whales, before being moved to Balaenoptera. The only known fossil of the species is a fragment of the left dentary, the tooth-bearing bone of the lower jaw, so little can be said about its size or appearance. The English Wikipedia article on Balaenoptera lists it among the valid fossil species of the genus, and the Paleobiology Database records it as an extinct marine suspension feeder of the Piacenzian age of the Pliocene.