Compared with terrestrial predators, the ~90 species of cetaceans (WoRMS 2012) ranging from wolf-sized to the largest animals ever, are a mind-boggling array. They’re the Pleistocene megafauna that, until recently, survived mostly intact (Anderson 2001) and no place on land, even Recent sub-Saharan Africa, can really compare with our oceans. It’s shocking that on top of this vast menagerie, one author claimed as many as 15 species remain to be discovered, including exotic beasts such as an 18 meter baleen whale with two dorsal fins (Raynal 2001). In a previous article I argued that particular hypothetical species, Amphiptera pacifica, was far more likely to be an early observation of (an anomalous?) Caperea than anything new and began to wonder if the discovery of unmistakable new species is at all probable. It isn’t.
The critical flaw with Raynal (2001) is that it conflates description and discovery. As for why this is problematic, the dolphin Tursiops australis was described in 2011 but the holotype was collected in 1914 and one lectotype is from 1902 (Charlton-Robb et al. 2011). Differences between the “new” species and other Bottlenose Dolphins are very subtle, so there’s no reason to think the 1902 specimen was the first our species ever encountered. I’d wager that encounter took place closer to 40,000 years ago. There is of course no way to determine who really discovered a species, but determining the earliest scientifically-documented specimen should be more feasible.
It didn’t work out as well as I expected; for 32 of the 90 species I used, the original source did not give a date for the holotype, no holotype existed, or I failed to locate the source. This resulted in me using the same date for “discovery” as the description, an event which only actually happened once (Lahille 1912). As I planned on finishing this article… ever, I was primarily concerned with holotypes, so there are undoubtedly many earlier specimens I overlooked. My limited data still managed to find a difference of 12.6 years between description and discovery; for the 58 species with data, this average was 19.3 years. Strikingly, the four species described in the 21st Century were on average discovered 55 years earlier, with the most recent being from 1976. Here is a decade-by-decade comparison of description and “discovery”:
It’s interesting how the “discovery” data appears to have a more normal (“bell curve”) distribution. Furthermore, the average date of discovery (1841.5) is closer to the first description (1675, 166.5 years) than the present (171.5 years). This does not bode well for new discoveries and again, I have to point out that most of my dates for “discovery” are probably far too late. For an alternate view, here is a graph of cumulative species descriptions and “discoveries”:
The last cetacean to be “discovered” was Balaenoptera omurai in 1976 and it is certainly notable they were initially considered to be small “form” of Bryde’s Whales (Sasaki et al. 2006). The first Mesoplodon perrini specimen (not a holotype) was discovered in 1975 and mistaken for M. hectori (Dalebout et al. 2002). Mesoplodon peruvianus has a holotype from 1975, but one beached specimen was photographed as early as 1955 (Reyes et al. 1991; Pitman & Lynn 2001). The porpoise Neophocaena asiaeorientalis was described in 1972 but the holotype was from 1922 (Helgen & McFadden 2001). So not only is there a sizable gap between description and discovery in these recent cases, all of the species have close relatives they either have been or could be confused for. If there are still cetaceans out there awaiting discovery, it would seem far more likely that they’re lookalikes hiding in plain sight than the fantastical species Raynal (2001) proposed.
Don’t get me wrong, I think that exciting discoveries will continue to be made about cetaceans; Orcas come in numerous distinct forms and it’s likely other dolphins have some fairly distinct inshore/offshore forms as well, plus there are still some very mysterious beaked whales roaming around.
References:
Anderson, P. (2001) Marine Mammals in the Next One Hundred Years: Twilight for a Pleistocene Megafauna? Journal of Mammalogy 82(3) 623—629 Semi-Available
Andrews, R. (1908) Description of a new species of Mesoplodon from Canterbury Province, New Zealand. Bulletin of the American Museum of Natural History 24 203—215. Available
Anderson, J. (1878) Anatomical and zoological research; comprising an account of zoological results of two expeditions to western Yunnan in 1868 and 1875. Available
Beasley, I et al. (2005) Description of a new dolphin, the Australian snubfin dolphin Orcaella heinsohni sp. n. (Cetacea, Delphinidae). Marine Mammal Science 21(3) 365—400. Available
Brownell, R. et al. (2009) Behavior of Melon-Headed Whales, Peponocephala electra, Near Oceanic Islands. Marine Mammal Science. Available
de Blainville, H. (1838) Sur les cachalots. Ann. fr. étrang. Anat. Physiol. 2 :335—337. Available
Catalog of Living Whales. http://www.ubio.org/apps/Hershkovitz/index.php?func=s&ID=2&t=s
Dalebout, M. et al. (2002) A new species of beaked whale Mesoplodon perrini sp. n. (Cetacea: Ziphiidae) discovered through phylogenetic analyses of mitochondrial DNA sequences. Marine Mammal Science 18, 577-608. Available
Cuvier, G. (1812). Rapport fait à la classe des Sciences mathématiques et physiques, sur divers Cétacés pris sur les côtes de France, pricipalement sur ceux qui sont échoués près de Paimpol, le 7 janvier 1812. Annales du Muséum d’Histoire naturelle 19 13—14. Available
Flower, W. (1882) On the cranium of a new species of Hyperoodon from the Australian seas. Proceedings of The Zoological Society of London 1882 392—396. Available
Gervais, P. (1855) Histoire naturelle des Mamifères. Available
Gray J. (1866) Catalogue of seals and whales in the British Museum. Available
Gray, J. (1865). Notes on the whales of the Cape; by E. L. Layard, Esq., of Cape-Town, Corr. Memb. with descriptions of two new species. Proceedings of the Zoological Society of London 1865 357—359. Available
Gray, J. (1846) Zoology of the voyage of H.M.S. Erebus and Terror. Available
Gray, J. (1828). Spicilegia Zoologica Or Original Figures and Short Systematic Descriptions of New and Unfigured Animals. Available
Helgen, K. & McFadden, T. (2001) Type specimens of recent mammals in the Museum of Comparative Zoology. Bulletin of the Museum of Comparative Zoology 157(2) 93—181. Available
de Lacépède, B. (1804). Histoire naturelle des cétacées. Available
Lahille, F. (1912) Nota preliminar sobre una nueva especie de Marsopa del rio dela Plata. (Phocaena dioptrica). Anales del Museo Nacional de Historia Natural de Buenos Aires (23) 269—278. Available
Mignucci-Giannoni, A. et al. (1999) New records of Fraser’s dolphin (Lagenodelphis hosei) for the
Caribbean. Aquatic Mammals 25(1) 15—19. Available
Owen, R. (1866) On some Indian Cetacea collected by Walter Elliot, Esq. Transactions of the Zoological Society 6(1) 10—14. Available
Owen, R. (1846) A history of British fossil mammals, and birds. Available
Peale, T. (1848) United States Exploring Expedition during the years 1838, 1839, 1840, 1841, 1842. VIII. Mammalia and ornithology. Available
Pitman, R. & Lynn, M. (2001) Biological observations of an unidentified mesoplodont whale in the Eastern Tropical Pacific and probable identity: Mesoplodon peruvianus. Marine Mammal Science 17 648—657. Available
Quoy, J. & Gaimard, J. (1824) Voyage autour du monde […] l’Oranie et la Physicienne […] Zoologie. Available
Raynal, M. (2001) Cryptocetology and Mathematics: How Many Cetaceans Remain To Be Discovered? Dracontology 81—96. Available.
Raynal, M. & Sylvestre, J.-P. (1991) Cetaceans with two dorsal fins. Aquatic Mammals 17(1) 31—36. Available
Reyes, J. et al. (1991) A new species of Beaked Whale Mesoplodon peruvianus sp. n. (Cetacea: Ziphiidae) from Peru. Marine Mammal Science 7(1) 1—24.
Rudulph, P. & Smeenk, C. (2009) Indo-West Pacific Marine Mammals IN: Perrin, W. et al. (eds.) Encyclopedia of Marine Mammals.
Sasaki, T. et al. (2006) Balaenoptera omurai is a newly discovered baleen whale that represents an ancient evolutionary lineage. Molecular Phylogenetics and Evolution 41 40—52. Available
True, F. (1885) On a new species of porpoise, Phocoena dalli, from Alaska. Proceedings of the United States National Museum 8(7) 95—98. Available
von Haast, J. (1876) On Oulodon: a new genus of Ziphioid Whales. Transactions of the Royal Society of New Zealand 9 450—458. Available
Weir C. (2010) A review of cetacean occurrence in West African waters from the Gulf of Guinea to Angola. Mammal Review 40(1) 2—39. Available
WoRMS (2012). Cetacea. IN: Perrin, W. (2012) World Cetacea Database. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=2688 on 2013-01-05
| Species | Description | “Discovery” | Notes – Sources |
| Balaena mysticetus | 1758 | 1758 | No Holotype (based on earlier descriptions) – WoRMS |
| Eubalaena australis | 1822 | 1818 | Lectotype – WoRMS |
| Eubalaena glacialis | 1776 | 1742 | No Holotype, date for earlier description – WoRMS |
| Eubalaena japonica | 1818 | 1818 | Holotype is a drawing! – WoRMS |
| Balaenoptera acutorostrata | 1804 | 1791 | No Holotype, early stranded individual – WoRMS |
| Balaenoptera bonaerensis | 1867 | 1867 | Cannot find original source |
| Balaenoptera borealis | 1828 | 1819 | Holotype – WoRMS |
| Balaenoptera edeni | 1878 | 1852 | Holotype – Anderson (1878) |
| Balaenoptera musculus | 1758 | 1738 | No Holotype, date for earlier description – WoRMS |
| Balaenoptera omurai | 2003 | 1976 | Earliest specimens – Rudolph & Smeenk (2009) |
| Balaenoptera physalus | 1758 | 1675 | No Holotype, date for earlier description – WoRMS |
| Megaptera novaeangliae | 1781 | 1741 | No Holotype, date for earlier description – Catalog of Whales |
| Eschrichtius robustus | 1861 | 1725 | Date for earlier, invalid description – Catalog of Whales |
| Caperea marginata | 1846 | 1846 | No date for Holotype – Gray (1846) |
| Cephalorhynchus commersonii | 1804 | 1804 | No holotype (sighting), no date – Lacépède (1804) |
| Cephalorhynchus eutropia | 1846 | 1846 | No date for Holotype – Gray (1846) |
| Cephalorhynchus heavisidii | 1828 | 1828 | No date for Holotype – Gray (1828) |
| Cephalorhynchus hectori | 1881 | 1873 | Date for earlier, invalid description – Catalog of Whales |
| Delphinus delphis | 1758 | 1738 | No Holotype, date for earlier description – Catalog of Whales |
| Delphinus capensis | 1828 | 1828 | No date for Holotype – Gray (1828) |
| Feresa attenuata | 1874 | 1827 | Early invalid synonym – WoRMS |
| Globicephala macrorhynchus | 1846 | 1846 | No date for Holotype – Gray (1846) |
| Globicephala melas | 1809 | 1806 | Lectotype – WoRMS |
| Grampus griseus | 1812 | 1811 | Date for holotype being received – Cuvier (1812) |
| Lagenodelphis hosei | 1956 | 1895 | Holotype purchased in 1895, found prior -Mignucci-Giannoni et al. (1999) |
| Lagenorhynchus acutus | 1828 | 1828 | No date for Holotype – Gray (1828) |
| Lagenorhynchus albirostris | 1846 | 1846 | No date for Holotype – Gray (1846) |
| Lagenorhynchus australis | 1848 | 1848 | Cannot find original source |
| Lagenorhynchus cruciger | 1824 | 1820 | No Holotype, date for observation – Quoy & Gaimard (1824) |
| Lagenorhynchus obliquidens | 1865 | 1855 | Date Holotype was cataloged – WoRMS |
| Lagenorhynchus obscurus | 1828 | 1828 | No date for Holotype – Gray (1828) |
| Lissodelphis borealis | 1848 | 1848 | No Holotype, no date for earliest encounter – Peale (1848) |
| Lissodelphis peronii | 1804 | 1802 | Date may or may not be for type specimen – WoRMS |
| Orcaella brevirostris | 1866 | 1866 | No date for Holotype – Owen in Gray (1866) |
| Orcaella heinsohni | 2005 | 1948 | Paratype – Beasley et al. (2005) |
| Peponocephala electra | 1846 | 1841 | Holotype – Brownell et al. (2009) |
| Pseudorca crassidens | 1846 | 1843 | Holotype – Owen (1846) |
| Sotalia fluviatilis | 1853 | 1853 | Cannot find original source |
| Sotalia guianensis | 1864 | 1858 | Paratypes? – Catalog of Living Whales |
| Sousa chinensis | 1765 | 1765 | No Holotype, date for sighting. Can’t determine date, original text too Swedish – WoRMS |
| Sousa teuszii | 1892 | 1891 | Holotype – Weir (2010) |
| Stenella attenuata | 1846 | 1846 | No date for Holotype – Gray (1846) |
| Stenella clymene | 1850 | 1846 | Earlier date for invalid description – WoRMS |
| Stenella coeruleoalba | 1833 | 1833 | Cannot find original source |
| Stenella frontalis | 1829 | 1825 | Holotype – WoRMS |
| Stenella longirostris | 1828 | 1828 | No date for Holotype – Gray (1828) |
| Sotalia fluviatilis | 1853 | 1853 | Cannot find original source |
| Sotalia guianensis | 1864 | 1858 | Holotype – WoRMS |
| Steno bredanensis | 1828 | 1817 | Date for earlier, invalid description – Catalog of Whales |
| Tursiops aduncus | 1832 | 1832 | Cannot find original source |
| Tursiops australis | 2011 | 1902 | Lectotype – Charlton-Robb et al. (2011) |
| Tursiops truncatus | 1821 | 1814 | Holotype – WoRMS |
| Inia boliviensis | 1834 | 1790 | Holotype – Catalog of Living Whales |
| Inia geoffrensis | 1817 | 1812 | Date for earlier, invalid description – Catalog of Whales |
| Kogia sima | 1866 | 1853 | Holotype – Owen (1866) |
| Kogia breviceps | 1838 | 1838 | No date for Holotype – de Blainville (1938) |
| Lipotes vexillifer | 1918 | 1916 | Holotype – WoRMS |
| Delphinapterus leucas | 1776 | 1773 | Date for earlier, invalid description – Catalog of Whales |
| Monodon monoceros | 1758 | 1758 | No Holotype (based on earlier descriptions) – WoRMS |
| Neophocaena asiaeorientalis | 1972 | 1922 | Holotype – Helgen & McFadden (2001) |
| Neophocaena phocaenoides | 1829 | 1829 | No date for Holotype |
| Phocoena dioptrica | 1912 | 1912 | Holotype – Lahille (1912) |
| Phocoena phocoena | 1758 | 1758 | No Holotype (based on earlier descriptions) – WoRMS |
| Phocoena sinus | 1958 | 1950 | Holotype – WoRMS |
| Phocoena spinipinnis | 1865 | 1865 | Cannot find original source |
| Phocoenoides dalli | 1885 | 1873 | Holotype – True (1885) |
| Physeter macrocephalus | 1758 | 1758 | No Holotype – WoRMS |
| Platanista gangetica | 1801 | 1797 | Holotype – WoRMS |
| Pontoporia blainvillei | 1844 | 1844 | Cannot find original source |
| Berardius arnuxii | 1851 | 1846 | Holotype – WoRMS |
| Berardius bairdii | 1883 | 1882 | Holotype – WoRMS |
| Hyperoodon ampullatus | 1770 | 1717 | No Holotype, early stranded individual – WoRMS |
| Hyperoodon planifrons | 1882 | 1882 | No date for Holotype – Flower (1882) |
| Indopacetus pacificus | 1926 | 1882 | Holotype – WoRMS |
| Mesoplodon bidens | 1804 | 1800 | Holotype – WoRMS |
| Mesoplodon bowdoini | 1908 | 1904 | Holotype – Andrews (1908) |
| Mesoplodon carlhubbsi | 1963 | 1946 | Holotype – WoRMS |
| Mesoplodon densirostris | 1817 | 1817 | Cannot find original source |
| Mesoplodon europaeus | 1855 | 1850 | Approximate date for early, invalid description – Catalog of Living Whales |
| Mesoplodon ginkgodens | 1958 | 1957 | Holotype – WoRMS |
| Mesoplodon grayi | 1876 | 1875 | Holotype – von Haast 1876 |
| Mesoplodon hectori | 1871 | 1866 | Holotype – WoRMS |
| Mesoplodon layardii | 1865 | 1865 | No date for Holotype – Gray (1865) |
| Mesoplodon mirus | 1913 | 1912 | Holotype – WoRMS |
| Mesoplodon perrini | 2002 | 1975 | Paratype – Dalebout et al. (2002) |
| Mesoplodon peruvianus | 1991 | 1955 | Individual known only from photographs – Pitman & Lynn (2001) |
| Mesoplodon stejnegeri | 1885 | 1883 | Holotype – WoRMS |
| Mesoplodon traversii | 1874 | 1872 | Holotype – WoRMS |
| Tasmacetus shepherdi | 1937 | 1933 | Holotype – WoRMS |
| Ziphius cavirostris | 1823 | 1804 | Holotype – WoRMS |
Biological Marginalia 
