Archaebalaenoptera castriarquati

Archaebalaenoptera castriarquati is an extinct rorqual and the type species of the genus Archaebalaenoptera, which is known from late Miocene to Pliocene marine deposits of the Netherlands, northern Italy and Peru. It was discovered in 1983 in sediments of the late Pliocene (Piacenzian) Castell'Arquato Formation in northern Italy, which gives the species its name. A cladistic analysis of the family Balaenopteridae recovered the genus as one of the most primitive rorquals, if not the most primitive. The shape of its jaw suggests that it probably could not ram feed the way living rorquals and humpback whales do. A second species of the genus, Archaebalaenoptera liesselensis from the Breda Formation near Liessel in the Netherlands, is larger than this type species.