Sagmatias Explained

Sagmatias was a genus of dolphins, defined in 1866 by Edward Drinker Cope^[1] with Peale's dolphin as type species, described as Sagmatias amblodon. It has been proposed to resurrect the genus to include four species of oceanic dolphins currently classified in the genus Lagenorhynchus.^[2] Mitochondrial DNA studies have indicated that Pacific white-sided dolphin, Peale's dolphin, dusky dolphin and hourglass dolphin are more closely related to dolphins in the Lissodelphininae subfamily, than to the two other members of the genus: Atlantic white-sided dolphin and white-beaked dolphin.^[3] This phylogenetic relationship is further supported by cladistic analysis of morphological characters.^[4] However, resurrection of the genus Sagmatias has not been accepted by the Society for Marine Mammalogy's taxonomic Committee, because the finer details of the phylogenetic relationships between the four species in the proposed Sagmatias genus and the four species of dolphins in the genus Cephalorhynchus remains to be resolved.^[5] Genetic and bioacoustical evidence suggest that Peale's dolphin and hourglass dolphin are closer related to the Cephalorhynchus species than to the Pacific white-sided dolphin and dusky dolphin,^{[6] [7] [8]} which, if true, would make the genus Sagmatias paraphyletic.

Notes and References

1. Cope . E.D. . Third contribution to the history of the Balaenidae and Delphinidae . Proceedings of the Academy of Natural Sciences of Philadelphia . 1866 . 293–300.
2. Vollmer . Nicole L. . Ashe . Erin . Brownell . Robert L. . Cipriano . Frank . Mead . James G. . Reeves . Randall R. . Soldevilla . Melissa S. . Williams . Rob . 2019 . Taxonomic revision of the dolphin genus Lagenorhynchus . Marine Mammal Science . 35 . 3 . 957–1057 . 10.1111/mms.12573 . 92421374 . 1748-7692 . en .
3. Leduc . R. . Perrin . W.. Dizon . E. . August 18, 1998 . Phylogenetic Relationships among the Delphinid Cetaceans Based on Full Cytochrome B Sequences . Marine Mammal Science . 15 . 3 . 619–648 . 10.1111/j.1748-7692.1999.tb00833.x.
4. Murakami . Mizuki . Shimada . Chieko . Hikida . Yoshinori . Soeda . Yuhji . Hirano . Hiromichi . Eodelphis kabatensis, a new name for the oldest true dolphin Stenella kabatensis Horikawa, 1977 (Cetacea, Odontoceti, Delphinidae), from the upper Miocene of Japan, and the phylogeny and paleobiogeography of Delphinoidea" . Journal of Vertebrate Paleontology . 2014 . 34 . 3 . 491–511 . 10.1080/02724634.2013.816720. 85210375 . free .
5. Web site: List of marine mammal species and subspecies . Society for Marine Mammalogy . en.
6. May-Collado . Laura . Agnarsson . Ingi . Cytochrome b and Bayesian inference of whale phylogeny . Molecular Phylogenetics and Evolution . February 2006 . 38 . 2 . 344–354 . 10.1016/j.ympev.2005.09.019. 16325433 .
7. Tougaard . J. . Kyhn . L. A. . Echolocation sounds of hourglass dolphins (Lagenorhynchus cruciger) are similar to the narrow band high-frequency echolocation sounds of the dolphin genus Cephalorhynchus . Marine Mammal Science . 28 December 2009 . 26 . 1 . 239–245 . 10.1111/j.1748-7692.2009.00307.x . 0824-0469 . 497138903. free .
8. Kyhn . L. A. . Jensen . F. H. . Beedholm . K. . Tougaard . J. . Hansen . M. . Madsen . P. T. . Echolocation in sympatric Peale's dolphins (Lagenorhynchus australis) and Commerson's dolphins (Cephalorhynchus commersonii) producing narrow-band high-frequency clicks . Journal of Experimental Biology . 1 June 2010 . 213 . 11 . 1940–1949 . 10.1242/jeb.042440. 20472781 . 207169275 .
9. Pichler . F. B. . Robineau . D. . Goodall . R. N. P. . Meyer . M. A. . Olivarria . C. . Baker . C. S. . Origin and radiation of Southern Hemisphere coastal dolphins (genus Cephalorhynchus) . Molecular Ecology . September 2001 . 10 . 9 . 2215–2223 . 10.1046/j.0962-1083.2001.01360.x. 11555263 . 24368161 .