Differences between the beaked whales Mesoplodon mirus and Mesoplodon gervaisi. American Museum novitates ; no. 1831

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New York, N.Y. : American Museum of Natural History
"A stranding of a young male Mesoplodon mirus True is reported from Flagler Beach, Florida - the most southern record for the species. The distribution of occurrences of Mesoplodon mirus and Mesoplodon gervaisi Deslongchamps are charted, and evidence of geographic segregation of the two species is noticed and discussed. Mesoplodon mirus apparently occupies the temperate western North Atlantic, and gervaisi the tropical and near tropical western North Atlantic. Eighteen proposed skull differences between Mesoplodon mirus and M. gervaisi are tested on the two specimens of the former and three of the latter in the American Museum of Natural History, and to some extent on published photographs of other specimens. Five of these propositions are found to be good, or modifiable so that they distinguish this material, and two others are found to be useful as supporting evidence. In addition to the interspecific differences concurred in by this testing of the 18 skull chracters, some intraspecific differences are observed in gervaisi. Part of this variation is shown to be sexual dimorphism, and the studied gervaisi material is sorted by it into three females and three males. Individual variation is evidently greater in the males. Comparison of external body measurements suggests that the length of the flipper of mirus generally exceeds that of gervaisi in proportion to total body length. Comparison of 31 skull measurements of the two species reveals nine measurements which, used collectiely, will separate skulls of these two species"--P. 23-24.
25 p. : ill., maps ; 24 cm.
Includes bibliographical references (p. 24-25).