CLASSIFICATION OF CETACEANS

In addition to the two suborders (Mysticeti and Odontoceti), the cetacean order contains numerous families, genera, and species. Each of these groupings represents a progressively more specialized division of the animals into categories on the basis of similarities in their skulls, postcranial skeletons, and external characteristics. The discipline which concerns itself with naming an animal and assigning it to its appropriate scientific category is known as taxonomy. An example of the classification of a cetacean species is shown in the following:

SCIENTIFIC CLASSIFICATION OF THE ATLANTIC BOTTLENOSED DOLPHIN

Kingdom:Animaliaall animals

Phylum:Chordatahaving at some stage a notochord, the precursor of the backbone

Subphylum:Vertebrataanimals with backbones—fishes, amphibians, reptiles, birds, and mammals

Class:Mammaliaanimals that suckle their young

Order:Cetaceacarnivorous, wholly aquatic mammals: whales, including dolphins and porpoises

Suborder:Odontocetitoothed whales as distinguished from Mysticeti, the baleen whales

Family:Delphinidaedolphins

Genus:Tursiopsbottlenosed dolphins

Species:truncatusAtlantic bottlenosed dolphin

Modern taxonomy had its origin with the Swedish naturalist Linnaeus, whose tenth edition of the Systema Naturae in 1758 forms the official starting point. Following Linnaeus, modern scientific names consist of two words, a generic name, which has an initial capital, and a species name, which rarely does, occasionally in botany (some species names deriving from a person's name are capitalized). Both names are usually of Latin origin (sometimes Greek) and are italicized or underlined. These scientific names are of particular importance because, although common names of species often are different in different countries or even in different regions of the same country, the scientific name remains the same. For example, the right whale is universally known as Eubalaena glacialis though its common names include black right whale, nordcaper, sletbag, Biscay whale, and Biscayan right whale.

Although classification of many species is still in a state of flux, the classification of western North Atlantic cetaceans followed in this guide is as follows:

Page of synoptic account of the species

Order Cetacea

Suborder Mysticeti—Baleen whales

Family Balaenopteridae—Rorquals

Balaenoptera acutorostrataLacepede 1804Minke whale63

Balaenoptera physalus(Linnaeus 1758)Fin whale26

Balaenoptera musculus(Linnaeus 1758)Blue whale19

Balaenoptera borealisLesson 1828Sei whale32

Balaenoptera edeniAnderson 1879Bryde's whale37

Megaptera novaeangliae(Borowski 1781)Humpback whale40

Family Balaenidae—Right whales

Balaena mysticetusLinnaeus 1758Bowhead whale49

Eubalaena glacialis(Borowski 1781)Right whale52

Suborder Odontoceti—Toothed whales

Family Ziphiidae

Mesoplodon bidens(Sowerby 1804)North Sea beaked whale82

Mesoplodon densirostris(Blainville in Desmarest 1817)Dense-beaked whale80

Mesoplodon europaeus(Gervais 1855)Antillean beaked whale78

Mesoplodon mirusTrue 1913True's beaked whale77

Ziphius cavirostrisG. Cuvier 1823Goosebeaked whale70

Hyperoodon ampullatus(Forster 1770)Northern bottlenosed whale67

Family Physeteridae

Physeter catodonLinnaeus 1758Sperm whale57

Kogia breviceps(Blainville 1838)Pygmy sperm whale144

Kogia simus(Owen 1866)Dwarf sperm whale148

Family Monodontidae

Monodon monocerosLinnaeus 1758Narwhal102

Delphinapterus leucas(Pallas 1776)Beluga99

Family Stenidae

Steno bredanensis(G. Cuvier in Lesson 1828)Rough-toothed dolphin135

Sotalia guianensis(P. J. van Beneden 1864)Guiana dolphin132

Family Delphinidae

Peponocephala electra(Gray 1846)Many-toothed blackfish142

Feresa attenuataGray 1874Pygmy killer whale138

Pseudorca crassidens(Owen 1846)False killer whale88

Globicephala melaena(Traill 1809)Atlantic pilot whale91

Globicephala macrorhynchusGray 1846Short-finned pilot whale94

Orcinus orca(Linnaeus 1758)Killer whale84

Lagenorhynchus albirostrisGray 1846White-beaked dolphin126

Lagenorhynchus acutus(Gray 1828)Atlantic white-sided dolphin123

Lagenodelphis hoseiFraser 1956Fraser's dolphin120

Tursiops truncatus(Montagu 1821)Bottlenosed dolphin128

Grampus griseus(G. Cuvier 1812)Grampus96

Stenella longirostrisGray 1828Spinner dolphin110

Stenella frontalis(G. Cuvier 1829)Bridled dolphin108

Stenella coeruleoalba(Meyen 1833)Striped dolphin113

Stenella plagiodon(Cope 1866)Spotted dolphin104

Delphinus delphisLinnaeus 1758Saddleback dolphin116

Family Phocoenidae

Phocoena phocoena(Linnaeus 1758)Harbor porpoise150

This tentative classification follows an unpublished list by W.E. Schevill and E.M. Mitchell currently under review. The scientific names are followed by the name of the individual who named the species and the year of naming, and then by the common name most often used in the western North Atlantic.[6] It may be noted that some of the authors are in parentheses. This indicates that though the species name has remained the same since the date of naming the species has since been assigned to another genus. Because the species are not arranged in taxonomic order in this field guide, the page of the synoptic account of each is provided in the column to the right.

Figure 1.—The western North Atlantic, from lat. 35°N-65°N.

Figure 2.—The western North Atlantic, from lat. 37°N south to eastern Venezuela.

Figure 3.—A baleen whale (humpback) showing the main body parts referred to in the text.

Figure 4.—A fin whale in the North Atlantic with the paired blowholes open during respiration. The paired blowholes distinguish this animal as a baleen whale. (Photo by W. A. Watkins.)