A team of marine biologists has made the first ever observations of rare Omura’s whales, one of the least known species of whales in the world.
Omura’s whales are so rare that scientists are not sure exactly how many exist.
Omura’s whale or the dwarf fin whale (Balaenoptera omurai) is a species of rorqual about which very little is known. Before its formal description, it was referred to as a small, “dwarf” or “pygmy” form of Bryde’s whale by various sources (including Ohsumi 1978, Wada and Numachi 1991, Carwardine 1995, Perrin et al. 1996, Kahn 2001, LeDuc and Dizon 2002, Kato 2002, among many others). The common name and specific epithet commemorates Japanese cetologist Hideo Omura.
The scientific description of this whale was made in Nature in 2003 by three Japanese scientists. They determined the existence of the species by analysing the morphology and mitochondrial DNA of nine individuals – eight caught by Japanese research vessels in the late 1970s in the Indo-Pacific and an adult female collected in 1998 fromTsunoshima, an island in the Sea of Japan. Later abundant genetic evidence confirmed Omura’s whale as a valid species and revealed it to be an early offshoot from the rorqual lineage, diverging much earlier than the Bryde’s and sei whales. It is perhaps more closely related to its larger cousin, the blue whale.
Balaenoptera omurai is known as Omura’s whale and is one of the least known species of whales in the world. Now, researchers have studied around 25 individuals in Madagascar, noticing unique asymmetrical pigmentation on the head:
A – asymmetrical coloration of the lower jaw
B – asymmetrical coloration of the gape
C – leading edge of pectoral fin white from tip to shoulder
D – apparent absence of lateral rostral ridges
E – lightly pigmented blaze originating anterior to the eye
F – lightly pigmented chevron anterior to dorsal fin
The study will continue on whales’ vocalizations, behavior and population characteristics.