Deraniyagala's beaked whale (''Mesoplodon hotaula'') is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

mesoplodont whale Mesoplodont whales are 16 species of toothed whale in the genus ''Mesoplodon'', making it the largest genus in the cetacean order (biology), order. Two species were described as recently as 1991 (pygmy beaked whale) and 2002 (Perrin's beaked wha ...

Taxonomy

Deraniyagala's beaked whale was once synonymous with the

Ginkgo-toothed beaked whale The ginkgo-toothed beaked whale (''Mesoplodon ginkgodens'') is a poorly known species of whale even for a beaked whale, and was named for the unusual shape of its dual teeth. It is a fairly typical-looking species, but is notable for the males no ...

(''Mesoplodon ginkgodens''), until several studies confirmed that ''M. hotaula'' was genetically different from ''M. ginkgodens''. Like several other species of beaked whales, Deraniyagala's beaked whale is known only from stranded individuals, in this case, seven. The first stranding occurred in Sri Lanka, but was falsely identified as Ginkgo-toothed beaked whale by Moore and Gilmore, 1965. The two species were split due to DNA analysis by various organisations in the 2000s, with the seven individuals' control region,

cytochrome b Cytochrome b within both molecular and cell biology, is a protein found in the mitochondria of eukaryotic cells. It functions as part of the electron transport chain and is the main subunit of transmembrane cytochrome bc1 and b6f complexes. F ...

cytochrome oxidase The enzyme cytochrome c oxidase or Complex IV, (was , now reclassified as a translocasEC 7.1.1.9 is a large transmembrane protein complex found in bacteria, archaea, and mitochondria of eukaryotes. It is the last enzyme in the respiratory electr ...

, and various

intron An intron is any nucleotide sequence within a gene that is not expressed or operative in the final RNA product. The word ''intron'' is derived from the term ''intragenic region'', i.e. a region inside a gene."The notion of the cistron .e., gene. ...

s taken for genetic analysis. It was found that genetic variance (Dα) of the cytochrome b between Deraniyagala's whale and the Ginkgo-toothed beaked whale was 8.2% ± 1.79%, whereas genetic variance range between 5.5% to 16.6% in other Mesoplodon species (the smaller the percentage, the lesser the genetic differences between the two species). It was first recognised by

Paules Edward Pieris Deraniyagala Paulus Edward Pieris Deraniyagala (1900–1976) was a Sri Lankan paleontologist, zoologist, and artist. Early life and education He was born in Colombo, the son of Paul Edward Pieris and Lady Hilda Obeyesekere Pieris. He had two younger brothers, ...

in 1963 and was subsequently named after him.

Distribution

Deraniyagala's beaked whale is known from only seven individuals that have stranded themselves on beaches of various islands in the

Indian Indian or Indians may refer to: Peoples South Asia * Indian people, people of Indian nationality, or people who have an Indian ancestor ** Non-resident Indian, a citizen of India who has temporarily emigrated to another country * South Asia ...

and South Pacific Oceans:

Seychelles Seychelles (, ; ), officially the Republic of Seychelles (french: link=no, République des Seychelles; Creole: ''La Repiblik Sesel''), is an archipelagic state consisting of 115 islands in the Indian Ocean. Its capital and largest city, V ...

Maldives Maldives (, ; dv, ދިވެހިރާއްޖެ, translit=Dhivehi Raajje, ), officially the Republic of Maldives ( dv, ދިވެހިރާއްޖޭގެ ޖުމްހޫރިއްޔާ, translit=Dhivehi Raajjeyge Jumhooriyyaa, label=none, ), is an archipelag ...

Sri Lanka Sri Lanka (, ; si, ශ්‍රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...

Gilbert Islands The Gilbert Islands ( gil, Tungaru;Reilly Ridgell. ''Pacific Nations and Territories: The Islands of Micronesia, Melanesia, and Polynesia.'' 3rd. Ed. Honolulu: Bess Press, 1995. p. 95. formerly Kingsmill or King's-Mill IslandsVery often, this n ...

Kiribati Kiribati (), officially the Republic of Kiribati ( gil, ibaberikiKiribati),Kiribati
''The Wor ...

and

Line Islands The Line Islands, Teraina Islands or Equatorial Islands (in Gilbertese, ''Aono Raina'') are a chain of 11 atolls (with partly or fully enclosed lagoons) and coral islands (with a surrounding reef) in the central Pacific Ocean, south of the Hawa ...

. It is thought that, like

Cuvier's beaked whale The Cuvier's beaked whale, goose-beaked whale, or ziphius (''Ziphius cavirostris'') is the most widely distributed of all beaked whales in the family Ziphiidae. It is smaller than most baleen whales yet large among beaked whales. Cuvier's beaked ...

, they live in insular populations (isolated communities). A potential sighting occurred in the

South China Sea The South China Sea is a marginal sea of the Western Pacific Ocean. It is bounded in the north by the shores of South China (hence the name), in the west by the Indochinese Peninsula, in the east by the islands of Taiwan and northwestern Phil ...

in May 2019, although it was possible the sighted whales were

ginkgo-toothed beaked whale The ginkgo-toothed beaked whale (''Mesoplodon ginkgodens'') is a poorly known species of whale even for a beaked whale, and was named for the unusual shape of its dual teeth. It is a fairly typical-looking species, but is notable for the males no ...

Diet

Like other mesoplodont whales, it is thought that Deraniyagala's whale feeds mainly on deep-sea squid-and-fish.

Conservation

Ocean debris has been mentioned as a possible threat for Deraniyagala's beaked whales. The individuals suspected to be members of the species sighted in 2019 had unusual indentations on the lips, which researchers believed could have been caused by marine debris or fishing line. Additionally, a stranded individual was found in on a beach in the Philippines in 2012, and died shortly after it was found. Further examination revealed that the whale had only a black rope and a piece of coal in its stomach. Researchers believed that the consumption of these items could have led to the whale's death.

References

Ziphiids Mammals described in 1963 {{Whale-stub

Taxonomy

Distribution

Diet

Conservation

See also

References