16 November 2012

How rare is rare? The discovery of the spade-toothed whale

Photo from Current Biology

In 1872, a partially damaged mandible (with teeth) of a beaked whale (Dolichodon layardii) was collected in Pitt Island, Chatham Islands, New Zealand.1 This specimen was later on determined to be the same species as the specimen identified as Mesoplodon ginkgodens collected in White Island, New Zealand in the 1950’s 2 and the specimen identified as Mesoplodon bahamondi collected in Robinson Crusoe Island, Juan Fernández Archipelago, Chile, in 19861. Genetic analyses determined that all three specimens belong to the species Mesoplodon traversii2. Little is known about the biology of this rare offshore species3, and the fact that there is no evidence of it being consumed as food confirms its rarity in the wild4. An adult female (17 feet) and a juvenile male (11.5 feet) were sighted on Opape Beach, North Island, New Zealand in December 2010, one of the rare observations made on this species.5

1van Helden, A.L.; Baker, A.N.; Dalebout, M.L.; Reyes, J.C.; van Waerebeek, K.; Baker, S.C. 2002. Resurrection of Mesoplodon traversii (Gray, 1874), senior synonym of M. bahamodi Reyes (van Waerebeek, Cárdenas and Yánez, 1995) (Cetacea Ziphiidae). Marine Mammal Science 18(3):609-621.
2 Baker, A.N.; van Helden, A.L. 1999. New records of beaked whale, Genus Mesoplodon, from New Zealand (Cetacea: Ziphiidae). Journal of the Royal Society of New Zealand 29(3):235–244.
3 France-Presse, A. 2012. Rarest whale spied in New Zealand. Cosmos: The Science of Everything http://www.cosmosmagazine.com/news/6139/rarest-whale-spied-new-zealand [Accessed 12 November 2012].
4 Robards, M.D.; Reeves, R.R. 2011. The global extent and character of marine mammal consumption by humans: 1970-2009.
5 Stromberg, J. 2012. The world’s rarest whale species spotted in New Zealand. Smithsonian Magazine http://blogs.smithsonianmag.com/science/2012/11/the-worlds-rarest-whale-species-spotted-in-new-zealand/ [Accessed 12 November 2012].

Written by:
Patricia S. Yap
Research Assistant
The SeaLifeBase Project

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