With the re-discovery of Mesoplodon hotaula, there are now 22 recognised species of beaked whales. The discovery is based on the study of seven animals stranded on remote tropical islands in the Indian and Pacific Oceans over the past 50 years.
The researchers used a combination of DNA analysis and physical characteristics to identify the new species from seven specimens found stranded in Sri Lanka, the Gilbert Islands (now Kiribati), Palmyra Atoll in the Northern Line Islands near Hawai'i, the Maldives, and the Seychelles.
The first specimen was a female found washed up on a Sri Lankan beach more than 50 years ago. At the time the National Museums of Ceylon, P.E.P (Paulus) Deraniyagala, described it as a new species, and named it Mesoplodon hotaula, after the local Singhala words for 'pointed beak'.
However, two years later, other researchers reclassified this specimen as an existing species, Mesoplodon ginkgodens , named for the tusk-like teeth of the adult males that are shaped like the leaves of a ginkgo tree.
"Now it turns out that Deraniyagala was right regarding the uniqueness of the whale he identified. While it is closely related to the ginkgo-toothed beaked whale, it is definitely not the same species," says international team leader, Dr Merel Dalebout, a visiting research fellow at UNSW.
They are rarely seen at sea due to their elusive habits, long dive capacity and apparent low abundance for some species. Understandably, most people have never heard of them.
— Dr Merel Dalebout