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 not having any scarring.[3]
Description
A ginko-toothed beaked whale skull located at the Okinawa Churaumi Aquarium, Japan.
Ginkgo-toothed beaked whales are more robust than most mesoplodonts, but otherwise look fairly typical. Halfway through the jaw, there is a sharp curve up where the ginkgo leaf-shaped tooth is.
The coloration is overall dark gray on males with light patches on the front half of the beak and around the head, and small white spots on the bottom of the tail, but the location may be variable. Females are a lighter gray and have countershading.
Both sexes reach 4.9 meters (16 feet) in length. They are around 2.4 meters (7.9 feet) long when born.
Unlike all other known members of Ziphiidae, there is no evidence that the males engage in combat, although this may be due to a limited sample size. The species probably feeds primarily on squid.[10] No other information is known.
Conservation
The only observations of this species while alive have come from hunters off the coasts of Japan and Taiwan, who occasionally take an individual. They are also affected by drift gillnets. One individual, identified from a DNA sample, was known to have interacted with a pelagiclongline fishery in the central and western Pacific Ocean. The ginkgo-toothed beaked whale is covered by the Memorandum of Understanding for the Conservation of Cetaceans and Their Habitats in the Pacific Islands Region (Pacific Cetaceans MOU).[11]
Specimens
MNZ MM002618/1, collected Pakawau, Golden Bay, New Zealand, 2004.
^Nishiwaki, M.; Kasuya, T.; Kureha, K.; Oguro, N. (1972). "Further comments on Mesoplodon ginkgodens"(PDF). Scientific Reports of the Whales Research Institute. 24: 43–56. Retrieved 26 February 2019.
^Dalebout, Merel Louise (2002). Species identity, genetic diversity, and molecular systematic relationships among the Ziphiidae (beaked whales). ProQuest: The University of Auckland (New Zealand). p. 249.
^Rosso, Massimiliano; Lin, Mingli; Caruso, Francesco; Liu, Mingming; Dong, Lijun; Borroni, Anna; Lin, Wenzhi; Tang, Xiaoming; Bocconcelli, Alessandro; Li, Songhai (2 December 2020). "First live sighting of Deraniyagala's beaked whale (Mesoplodon hotaula) or ginkgo‐toothed beaked whale (Mesoplodon ginkgodens) in the western Pacific (South China Sea) with preliminary data on coloration, natural markings, and surfacing patterns". Integrative Zoology. 16 (4): 451–461. doi:10.1111/1749-4877.12507. PMID33289310. S2CID227947326.
Encyclopedia of Marine Mammals. Edited by William F. Perrin, Bernd Wursig, and J.G.M Thewissen. Academic Press, 2002. ISBN0-12-551340-2
Sea Mammals of the World. Written by Randall R. Reeves, Brent S. Steward, Phillip J. Clapham, and James A. Owell. A & C Black, London, 2002. ISBN0-7136-6334-0
