List of Marine Mammal Species and Subspecies


The Committee on Taxonomy, produced the first official Society for Marine Mammalogy list of marine mammal species and subspecies in 2010 and is updated at least annually. The Committee is currently chaired by Ana Costa and its Terms of Reference provide information on the Committee’s process.

The current version was updated in June 2024. This list can be cited as follows: “Committee on Taxonomy. 2024. List of marine mammal species and subspecies. Society for Marine Mammalogy,, consulted on [date].”

The Committee considers and evaluates new, peer-reviewed literature that proposes taxonomic changes. The Committee’s focus is on alpha taxonomy (describing and naming taxa) and beta taxonomy primarily at lower levels of the hierarchy (subspecies, species and genera), although it may evaluate issues at higher levels if deemed necessary. Proposals for new, taxonomically distinct taxa require a formal, peer-reviewed study and should provide robust evidence that some subspecies or species criterion was met. For review of species concepts, see Reeves et al. (2004), Orr and Coyne (2004), de Queiroz (2007), Perrin (2009) and Taylor et al. (2017 a,b). Nomenclatural papers that propose new names are to be registered with ZooBank and publications should include required information including designation of holotype or syntype specimen(s), identification of the repository of the specimen(s), and explicit identification of the taxon as new by inclusion of a term such as “ssp. nov.”, “new species”, etc. See the Committee’s Taxonomic Guide for Authors for more information. The Committee also recommends authors acquaint themselves with the International Code of Zoological Nomenclature (ICZN 1999) and supply the information required under the Code when proposing new species or subspecies. Some examples of recent species or subspecies descriptions and redescriptions providing the necessary information can be seen at: Yamada et al. (2019), Rosel et al. (2021), Costa et al. (2023).

The Committee omits some described species and subspecies because of concern about their biological distinctness; reservations are given in the narrative below. In addition, published proposals for taxonomically distinct units that do not provide names and instead refer simply to ‘un-named subspecies’ or ‘un-named species’ are not included in the official list but are provided here. Authors are encouraged to provide formal descriptions following ICZN rules based on robust data showing an appropriate subspecies or species criterion is met.

The Committee does not arbitrate common names. Common names are arbitrary and change with time and place. In general, we aim to maintain established names currently in use whenever possible, use names suggested by the authors of new species or subspecies descriptions if present, and recognize multiple common names when multiple names are commonly used. One, or two, frequently used names in English and/or a range language are given here. Additional English common names and common names in French, Spanish, Russian and other languages are available at Species are listed in alphabetical order within families.

Corrections and comments should be directed to the Committee on Taxonomy ( Consensus on some issues has not been possible and divergent opinions by members of the Committee on particular taxonomic questions are given in the footnotes.

List of Marine Mammal Species and Subspecies

Order Carnivora

Family Ursidae

Ursus maritimus Linnaeus, 1758. Polar bear

Family Mustelidae

Enhydra lutris (Linnaeus, 1758). Sea otter

  • E. l. kenyoni Wilson, 1991. Eastern sea otter
  • E. l. lutris (Linnaeus, 1758). Western sea otter
  • E. l. nereis (Merriam, 1904). Southern sea otter

Lontra felina (Molina, 1782). Chungungo, marine otter

Neogale macrodon (Prentis, 1903). Sea mink (extinct)

PINNIPEDIA (eared seals, sea lions, walrus, earless seals; 36 species, of which 2 extinct)

Family Otariidae (eared seals and sea lions; 16 species, of which 1 extinct)

Arctocephalus australis (Zimmermann, 1783). South American fur seal

Arctocephalus forsteri (Lesson, 1828). Long-nosed fur seal, New Zealand fur seal

Arctocephalus galapagoensis Heller, 1904. Galapagos fur seal

Arctocephalus gazella (Peters, 1875). Antarctic fur seal

Arctocephalus philippii (Peters, 1866). Juan Fernandez fur seal

Arctocephalus pusillus (Schreber, 1775). Cape fur seal

  • A. p. doriferus Wood Jones, 1925. Australian fur seal
  • A. p. pusillus (Schreber, 1775). Cape fur seal

Arctocephalus townsendi (Merriam, 1897). Guadalupe fur seal

Arctocephalus tropicalis (Gray, 1872). Subantarctic fur seal

Callorhinus ursinus (Linnaeus, 1758). Northern fur seal

Eumetopias jubatus (Schreber, 1776). Steller sea lion, northern sea lion

  • E. j. jubatus (Schreber, 1776). Western Steller sea lion
  • E. j. monteriensis (Gray, 1859). Loughlin’s Steller sea lion

Neophoca cinerea (Peron, 1816). Australian sea lion

Otaria byronia (Blainville, 1820). South American sea lion

Phocarctos hookeri (Gray, 1844). New Zealand sea lion, Hooker’s sea lion

Zalophus californianus (Lesson, 1828). California sea lion

Zalophus japonicus (Peters, 1866). Japanese sea lion (extinct)

Zalophus wollebaeki Sivertsen, 1953. Galapagos sea lion

Family Odobenidae

Odobenus rosmarus (Linnaeus, 1758). Walrus

  • O. r. divergens (Illiger, 1815). Pacific walrus
  • O. r. rosmarus (Linnaeus, 1758). Atlantic walrus

Family Phocidae (earless seals; 19 species, of which 1 extinct)

Cystophora cristata (Erxleben, 1777). Hooded seal

Erignathus barbatus (Erxleben, 1777). Bearded seal

  • E. b. barbatus (Erxleben, 1777). Atlantic bearded seal
  • E. b. nauticus (Pallas, 1881). Pacific bearded seal

Halichoerus grypus (Fabricius, 1791). Gray seal

  • H. g. atlantica. Nehring, 1866. Atlantic gray seal
  • H. g. grypus (Fabricius, 1791). Baltic gray seal

Histriophoca fasciata (Zimmerman, 1783). Ribbon seal

Hydrurga leptonyx (Blainville, 1820). Leopard seal

Leptonychotes weddellii (Lesson, 1826). Weddell seal

Lobodon carcinophaga (Hombron and Jacquinot, 1842). Crabeater seal

Mirounga angustirostris (Gill, 1866). Northern elephant seal

Mirounga leonina (Linnaeus, 1758). Southern elephant seal

Monachus monachus (Hermann, 1779). Mediterranean monk seal

Neomonachus schauinslandi (Matschie, 1905). Hawaiian monk seal

Neomonachus tropicalis (Gray, 1850). Caribbean monk seal, West Indian monk seal (extinct)

Ommatophoca rossii Gray, 1844. Ross seal

Pagophilus groenlandicus (Erxleben, 1777). Harp seal

Phoca largha Pallas, 1811. Spotted seal, largha seal

Phoca vitulina Linnaeus, 1758. Harbor seal, common seal

  • P. v. mellonae Doutt, 1942. Ungava harbor seal
  • P. v. richardii (Gray, 1864). Pacific harbor seal
  • P. v. vitulina Linnaeus, 1758. Atlantic harbor seal

Pusa caspica (Gmelin, 1788). Caspian seal

Pusa hispida (Schreber, 1775). Ringed seal

  • P. h. botnica (Gmelin, 1788). Baltic ringed seal
  • P. h. hispida (Schreber, 1775). Arctic Ringed seal
  • P. h. ladogensis (Nordquist, 1889). Lake Ladoga seal
  • P. h. ochotensis (Pallas, 1811). Okhotsk ringed seal
  • P. h. saimensis (Nordquist, 1889). Saima seal

Pusa sibirica (Gmelin, 1788).  Baikal seal

Order ARTIODACTYLA (artiodactyls and cetaceans)

Infraorder CETACEA (cetaceans; 94 species, of which 1 possibly extinct)

MYSTICETI (baleen whales, 15 species)

Family Balaenidae (right whales, 4 species)

Balaena mysticetus Linnaeus, 1758. Bowhead whale, Greenland whale

Eubalaena australis (Desmoulins, 1822). Southern right whale

Eubalaena glacialis (Müller, 1776). North Atlantic right whale

Eubalaena japonica (Lacépède, 1818). North Pacific right whale

Family Neobalaenidae

Caperea marginata (Gray, 1846). Pygmy right whale

Family Eschrichtiidae

Eschrichtius robustus (Lilljeborg, 1861). Gray whale

Family Balaenopteridae (rorquals, 9 species)

Balaenoptera acutorostrata Lacépède, 1804. Common minke whale

  • B. a. acutorostrata Lacépède, 1804. North Atlantic minke whale
  • B. a. scammoni Deméré, 1986. North Pacific minke whale

Balaenoptera bonaerensis Burmeister, 1867. Antarctic minke whale

Balaenoptera borealis Lesson, 1828. Sei whale

  • B. b. borealis Lesson, 1828. Northern sei whale
  • B. b. schlegelii (Flower, 1865). Southern sei whale

Balaenoptera edeni Anderson, 1879. Bryde’s whale

  • B. e. brydei Olsen, 1913. Bryde’s whale
  • B. e. edeni Anderson, 1879. Eden’s whale

Balaenoptera musculus (Linnaeus, 1758). Blue whale

  • B. m. brevicauda Ichihara, 1966. Pygmy blue whale
  • B. m. indica Blyth, 1859. Northern Indian Ocean blue whale
  • B. m. intermedia Burmeister, 1871. Antarctic blue whale
  • B. m. musculus (Linnaeus, 1758). Northern blue whale

Balaenoptera omurai Wada, Oishi and Yamada, 2003. Omura’s whale

Balaenoptera physalus (Linnaeus, 1758). Fin whale

  • B. p. physalus (Linnaeus, 1758). North Atlantic fin whale
  • B. p. quoyi (Fischer, 1829). Southern fin whale
  • B. p. velifera Cope in Scammon, 1869. North Pacific fin whale

Balaenoptera ricei Rosel, Wilcox, Yamada and Mullin, 2021. Rice’s whale

Megaptera novaeangliae (Borowski, 1781). Humpback whale

  • M. n. australis (Lesson, 1828). Southern humpback whale
  • M. n. kuzira (Gray, 1850). North Pacific humpback whale
  • M. n. novaeangliae (Borowski, 1781). North Atlantic humpback whale

ODONTOCETI (toothed whales, dolphins and porpoises: 79 species, of which one possibly extinct)

Family Physeteridae

Physeter macrocephalus Linnaeus, 1758. Sperm whale, cachalot

Family Kogiidae

Kogia breviceps (Blainville, 1838). Pygmy sperm whale

Kogia sima (Owen, 1866). Dwarf sperm whale

Family Ziphiidae (beaked whales, 24 species)

Berardius arnuxii Duvernoy, 1851. Arnoux’s beaked whale

Berardius bairdii Stejneger, 1883. Baird’s beaked whale

Berardius minimus Yamada, Kitamura and Matsuishi, 2019. Sato’s beaked whale

Hyperoodon ampullatus (Forster in Kalm, 1770). Northern bottlenose whale

Hyperoodon planifrons Flower, 1882. Southern bottlenose whale

Indopacetus pacificus (Longman, 1926). Longman’s beaked whale, tropical bottlenose whale

Mesoplodon bidens (Sowerby, 1804). Sowerby’s beaked whale

Mesoplodon bowdoini Andrews, 1908. Andrews’ beaked whale

Mesoplodon carlhubbsi Moore, 1963. Hubbs’ beaked whale

Mesoplodon densirostris (Desmarest, 1817). Blainville’s beaked whale

Mesoplodon eueu Carroll et al. 2021.1 Ramari’s beaked whale

Mesoplodon europaeus (Gervais, 1855). Gervais’ beaked whale

Mesoplodon ginkgodens Nishiwaki and Kamiya, 1958. Ginkgo-toothed beaked whale

Mesoplodon grayi von Haast, 1876. Gray’s beaked whale

Mesoplodon hectori (Gray, 1871). Hector’s beaked whale

Mesoplodon hotaula Deraniyagala, 1963. Deraniyagala’s beaked whale

Mesoplodon layardii (Gray, 1865). Strap-toothed beaked whale, Layard’s beaked whale

Mesoplodon mirus True, 1913. True’s beaked whale

Mesoplodon perrini Dalebout, Mead, Baker, Baker and van Helden, 2002. Perrin’s beaked whale

Mesoplodon peruvianus Reyes, Mead and Van Waerebeek, 1991. Pygmy beaked whale

Mesoplodon stejnegeri True, 1885. Stejneger’s beaked whale

Mesoplodon traversii (Gray, 1874). Spade-toothed whale

Tasmacetus shepherdi Oliver, 1937. Shepherd’s beaked whale, Tasman beaked whale

Ziphius cavirostris G. Cuvier, 1823. Cuvier’s beaked whale, goose-beaked whale

Family Platanistidae

Platanista gangetica (Lebeck, 1801). Ganges river dolphin, susu

Platanista minor Owen, 1853. Indus river dolphin, bhulan

Family Iniidae

Inia geoffrensis (Blainville, 1817). Amazon river dolphin

  • I. g. boliviensis (d’Orbigny, 1834). Bolivian bufeo
  • I. g. geoffrensis (Blainville, 1817). Common boto

Family Lipotidae

Lipotes vexillifer Miller, 1918. Baiji, Yangtze river dolphin (possibly extinct)

Family Pontoporiidae

Pontoporia blainvillei (Gervais and d’Orbigny, 1844). Franciscana, toninha

Family Monodontidae

Delphinapterus leucas (Pallas, 1776). Beluga, white whale

Monodon monoceros Linnaeus, 1758. Narwhal

Family Delphinidae (38 species)

Cephalorhynchus commersonii (Lacépède, 1804). Commerson’s dolphin

  • C. c. commersonii (Lacépède, 1804). Commerson’s dolphin
  • C. c. kerguelenensis Robineau, Goodall, Pichler and C. S. Baker, 2007. Kerguelen dolphin

Cephalorhynchus eutropia (Gray, 1846). Chilean dolphin

Cephalorhynchus heavisidii (Gray, 1828). Heaviside’s dolphin

Cephalorhynchus hectori (Van Beneden, 1881). Hector’s dolphin

  • C. h. hectori (Van Beneden, 1881). South Island Hector’s dolphin
  • C. h. maui A. Baker, Smith and Pichler, 2002. Māui dolphin, North Island Hector’s dolphin

Delphinus delphis Linnaeus, 1758. Common dolphin

  • D. d. bairdii Dall, 1873.  Eastern Pacific long-beaked common dolphin
  • D. d. delphis Linnaeus, 1758.  Common dolphin
  • D. d. ponticus Barabash, 1935. Black Sea common dolphin
  • D. d. tropicalis van Bree, 1971. Indo-Pacific common dolphin

Feresa attenuata Gray, 1874. Pygmy killer whale

Globicephala macrorhynchus Gray, 1846. Short-finned pilot whale

Globicephala melas (Traill, 1809). Long-finned pilot whale

  • G. m. edwardii (A. Smith, 1834). Southern long-finned pilot whale
  • G. m. melas (Traill, 1809). North Atlantic long-finned pilot whale

Grampus griseus (G. Cuvier, 1812). Risso’s dolphin, grampus

Lagenodelphis hosei Fraser, 1956. Fraser’s dolphin

Lagenorhynchus acutus (Gray, 1828). Atlantic white-sided dolphin

Lagenorhynchus albirostris (Gray, 1846). White-beaked dolphin

Lagenorhynchus australis (Peale, 1849). Peale’s dolphin

Lagenorhynchus cruciger (Quoy and Gaimard, 1824). Hourglass dolphin

Lagenorhynchus obliquidens Gill, 1865. Pacific white-sided dolphin

Lagenorhynchus obscurus (Gray, 1828). Dusky dolphin

  • L. o. fitzroyi (Waterhouse, 1838). Fitzroy’s dolphin
  • L. o. obscurus (Gray, 1828). African dusky dolphin
  • L. o. posidonia (Philippi, 1893). Peruvian/Chilean dusky dolphin

Lissodelphis borealis (Peale, 1849). Northern right-whale dolphin

Lissodelphis peronii (Lacépède, 1804). Southern right-whale dolphin

Orcaella brevirostris (Owen in Gray, 1866). Irrawaddy dolphin, pesut

Orcaella heinsohni Beasley, Robertson and Arnold, 2005. Australian snubfin dolphin

Orcinus orca (Linnaeus, 1758). Killer whale, orca

  • O. o. ater (Cope in Scammon, 1869). Resident killer whale
  • O. o. orca (Linnaeus, 1758). Common killer whale
  • O. o. rectipinnus (Cope in Scammon, 1869). Bigg’s killer whale

Peponocephala electra (Gray, 1846). Melon-headed whale

Pseudorca crassidens (Owen, 1846). False killer whale

Sousa chinensis (Osbeck, 1765). Indo-Pacific humpback dolphin

  • S. c. chinensis (Osbeck, 1765). Chinese humpback dolphin
  • S. c. taiwanensis Wang, Yang and Hung, 2015. Taiwanese humpback dolphin, Taiwanese white dolphin

Sousa plumbea (G. Cuvier, 1829). Indian Ocean humpback dolphin

Sousa sahulensis Jefferson and Rosenbaum, 2014. Australian humpback dolphin

Sousa teuszii (Kükenthal, 1892). Atlantic humpback dolphin

Sotalia fluviatilis (Gervais and Deville in Gervais, 1853). Tucuxi

Sotalia guianensis (P.J. Van Beneden, 1864). Guiana dolphin, costero

Stenella attenuata (Gray, 1846). Pantropical spotted dolphin

  • S. a. attenuata (Gray, 1846). Offshore pantropical spotted dolphin
  • S. a. graffmani (Lönnberg, 1934). Coastal pantropical spotted dolphin

Stenella clymene (Gray, 1850). Clymene dolphin

Stenella coeruleoalba (Meyen, 1833). Striped dolphin

Stenella frontalis (G. Cuvier, 1829). Atlantic spotted dolphin

Stenella longirostris (Gray, 1828). Spinner dolphin

  • S. l. centroamericana Perrin, 1990. Central American spinner dolphin
  • S. l. longirostris (Gray, 1828). Gray’s spinner dolphin
  • S. l. orientalis Perrin, 1990. Eastern spinner dolphin
  • S. l. roseiventris (Wagner, 1846). Dwarf spinner dolphin

Steno bredanensis (Lesson, 1828). Rough-toothed dolphin

Tursiops aduncus (Ehrenberg, 1832). Indo-Pacific bottlenose dolphin

Tursiops erebennus (Cope, 1865). Tamanend’s bottlenose dolphin

Tursiops truncatus (Montagu, 1821). Common bottlenose dolphin

  • T. t. gephyreus Lahille, 1908. Lahille’s bottlenose dolphin
  • T. t. nuuanu Andrews, 1911. Eastern Tropical Pacific bottlenose dolphin
  • T. t. ponticus Barabash-Nikiforov, 1940. Black Sea bottlenose dolphin
  • T. t. truncatus (Montagu, 1821). Common bottlenose dolphin

Family Phocoenidae (porpoises, 7 species)

Neophocaena asiaeorientalis (Pilleri and Gihr, 1972). Narrow-ridged finless porpoise

  • N. a. asiaeorientalis (Pilleri and Gihr, 1972). Yangtze finless porpoise
  • N. a. sunameri Pilleri and Gihr, 1975. East Asian finless porpoise

Neophocaena phocaenoides (G. Cuvier, 1829). Indo-Pacific finless porpoise

Phocoena dioptrica Lahille, 1912. Spectacled porpoise

Phocoena phocoena (Linnaeus, 1758). Harbor porpoise

  • P. p. phocoena (Linnaeus, 1758). Atlantic harbor porpoise
  • P. p. relicta Abel, 1905. Black Sea harbor porpoise
  • P. p. vomerina (Gill, 1865). Pacific harbor porpoise

Phocoena sinus Norris and McFarland, 1958. Vaquita

Phocoena spinipinnis Burmeister, 1865. Burmeister’s porpoise

Phocoenoides dalli (True, 1885). Dall’s porpoise

  • P. d. dalli (True, 1885). dalli-type Dall’s porpoise
  • P. d. truei Andrews, 1911. truei-type Dall’s porpoise

ORDER SIRENIA (sirenians, 5 species, of which 1 extinct)

Family Trichechidae

Trichechus inunguis (Natterer, 1883). Amazonian manatee

Trichechus manatus Linnaeus, 1758. West Indian manatee

  • T. m. latirostris (Harlan, 1824). Florida manatee
  • T. m. manatus Linnaeus, 1758. Antillean manatee

Trichechus senegalensis Link, 1795. African manatee

Family Dugongidae

Dugong dugon (Müller, 1776). Dugong

Hydrodamalis gigas (Zimmerman, 1780). Steller’s sea cow (extinct)

Narrative on Taxonomy

Based on molecular and morphological data, the cetaceans fall firmly within the artiodactyl clade with hippopotamuses being the sister taxon to cetaceans (e.g., Geisler and Uhen, 2005, Spaulding et al. 2009) and Montgelard et al. (1997) proposed the taxon Cetartiodactyla, pooling even-toed terrestrial mammals and all cetaceans into a single Order. The Taxonomy Committee followed this convention, with some reservation, when it created the first list of marine mammal species and subspecies in 2009, and the term Cetartiodactyla has been widely used. Recently, Prothero et al. (2022) make a strong argument that the term Cetartiodactyla misrepresents taxonomic relationships as it implies cetaceans and artiodactyls are of equal rank, when, in fact, cetaceans are clearly nested within the Artiodactyla. We agree with Prothero et al. (2022) and revert to the use of Order Artiodactyla to include all cetacean taxa (living and extinct), and provisionally rank Cetacea as an Infraorder. While this change will likely cause some initial confusion, it more accurately reflects the placement of cetaceans in the taxonomic hierarchy. We continue to maintain Mysticeti and Odontoceti provisionally as unranked taxa (recognizing that the classification within Cetartiodactyla remains partially unresolved — e.g., see Spaulding et al. (2009), Price et al. (2005), Agnarsson and May-Collado (2008)).2

Below the rank of order, we list only families, genera, species and subspecies, omitting superfamilies, subfamilies and taxa of other ranks. We include the un-ranked taxon Pinnipedia. Morphological (Wyss and Flynn, 1993; Berta and Wyss, 1994) and molecular (Higdon et al. 2007; Fulton and Strobeck, 2010, Nyakatura and Bininda-Emonds 2012) analyses provide strong support for pinniped monophyly and hence inclusion of Pinnipedia as an un-ranked taxonomic unit. However, there is continued debate on this subject as Koretsky et al. (2016) argued the case for a diphyletic origin for pinnipeds.

Polar Bears and Otters

Derocher and Stirling (1998) argued convincingly that patterns of variation in the polar bear do not support recognition of subspecies.

The use of Lontra rather than Lutra for the marine otter follows Larivière (1998) in recognizing the otters of North and South America as a monophyletic taxon distinct from the otters of Eurasia.

Based on the review provided by Patterson et al. (2021), the genus of the sea mink (extinct) is now recognized as Neogale Gray, 1865.


For pinnipeds, we previously followed Berta and Churchill (2012). To avoid issues of paraphyly, these authors proposed that, based on molecular and morphological data, the genus Arctocephalus be limited to Arctocephalus pusillus, the type species of the genus Arctocephalus, and transferred the remaining ‘Arctocephalus’ species (i.e., A. australisA. galapagoensisA. gazellaA. philippii and A. tropicalis) to Arctophoca Peters, 1866. However, Nyakatura and Bininda-Emonds (2012) compiled a new supertree of the Carnivora and concluded that this usage of Arctophoca may be premature because of remaining uncertainty about phylogenetic relationships, and we return provisionally to use of Arctocephalus for all the southern fur seals. More recently, evidence presented in Lopes et al. (2021), based on genomic data and different phylogenetic approaches, support the monophyly of the genus Arctocephalus.

Three subspecies of A. australis were proposed by Berta and Churchill (2012) and formerly listed here: A. a. australisA. a. forsteri and A. a. gracilis. However, Oliveira and Brownell (2014) synonymized A. a. gracilis with A. a. australis. The super-tree analysis by Nyakatura and Bininda-Emonds (2012) accords with the phylogenetic analysis of Higdon et al. (2007), suggesting that the New Zealand fur seal should be recognized as a full species, A. forsteri. Previously, two subspecies of A. philippii (A. p. philippii and A. p. townsendi) were recognized, although they were thought to be biologically distinct, small sample sizes and a small number of genes sampled were at the time concerns. Recently, Lopes et al. (2021) used high-coverage genome-wide sequencing for 14 taxa in the Otariidae to elucidate the phylogeny of the family. A divergence time of ~0.6 Ma was estimated between townsendi and philippii, which is similar to or older than the divergence time of ~0.5 Ma estimated between two well-recognized species, A. australis and A. galapagoensis. The phylogenomic findings together with their geographic isolation led the authors to suggest that Juan Fernandez fur seal and Guadalupe fur seal be recognized as full species, a suggestion followed here.

Berta and Churchill (2012) suggested fur seals in Peru be recognized as a distinct subspecies based on results from Oliveira et al. (2008). Lopes et al. (2023) expanded genetic analysis on fur seals in South America and concluded that fur seals in Peru are of hybrid origin and deserve species-level recognition. However, further information on the degree of ongoing gene flow between fur seals in Peru and the two neighboring species would be helpful for a robust examination of the taxonomic status of these seals. Further, and importantly, a formal taxonomic description is absent from both publications. They therefore remain on the List of Proposed Un-named Species and Subspecies.

Two subspecies of Eumetopias are supported largely on molecular genetic data, which is also the case for recognition of California, Japanese and Galapagos sea lions as separate species.

Following a proposal by Gardner and Robbins (1999), the International Code of Zoological Nomenclature (ICZN) placed the name Obyronia on its Official List of Specific Names in Zoology. Brunner (2004) also advised use of Otaria byronia (Blainville, 1820) over O. flavescens (Shaw, 1800) and Webber (2014) provides a summary of why O. flavescens is a nomen dubium and should not be used under the provisions of the International Code of Zoological Nomenclature (ICZN 1999). However, many South American scientists continue to use O. flavescens.

Lindqvist et al. (2009) concluded that a purported third subspecies of the walrus Odobenus rosmarus laptevi is not warranted.

The long-lost holotype skull of the gray seal Halichoerus grypus has been rediscovered and shown by DNA analysis to hail from the Baltic rather than from Greenland as previously thought (Olsen et al. 2016). Consequently, the nominate subspecies H. g. grypus is the Baltic gray seal, H. g. macrorhynchus falls into synonymy, and the authors have resurrected H. g. atlantica to apply to the Atlantic subspecies.

Recent molecular genetic analyses indicate that Phoca vitulina concolor is paraphyletic and this along with lack of morphological differentiation suggests that the western Atlantic subspecies is not supportable; P. v. vitulina is considered here to apply to all Atlantic harbor seals. Within the North Pacific, until the subspecies limits of various populations are assessed, only a single subspecies is recognized, Phoca vitulina richardii. Placement of the ringed seal, Caspian seal and Baikal seal has alternated between the genera Phoca and Pusa. We accept Rice’s (1998) use of Pusa as the correct classification. Scheel et al. (2014) found the Caribbean and Hawaiian monk seals to be more closely related molecularly and morphologically to each other than either is to the Mediterranean monk seal and created the new genus Neomonachus for the two species.

Baleen Whales

In the mysticete cetaceans, molecular evidence strongly supports the recognition of three separate phylogenetic species of right whales (Rosenbaum et al. 2000; Gaines et al. 2005). In addition, the genus Eubalaena (rather than Balaena as in Rice, 1998) is retained for the right whales as recommended by the Scientific Committee of the International Whaling Commission (IWC, 2001).3

New fossil evidence suggests that Caperea marginata may be a member of the family Cetotheriidae (Fordyce and Marx 2012; Marx and Fordyce 2015; Marx and Fordyce 2016). Neobalaenidae is retained here provisionally.

Jackson et al. (2014) have recognized three subspecies of the humpback whale based on mitochondrial and nuclear DNA relationships and distribution: Megaptera novaeangliae kuzira (North Pacific), M. n. novaeangliae (North Atlantic) and M. n. australis (Southern Hemisphere).

There have been a variety of studies (McDonald et al. 2006, Branch et al. 2007, LeDuc et al. 2007, 2017, Torres-Florez et al. 2014, Buchan et al. 2018, Leslie et al. 2021) that have provided evidence suggesting blue whales in the eastern South Pacific differ from blue whales elsewhere and may represent a separate subspecies but none have provided a formal subspecies description supplying the information required under the International Code of Zoological Nomenclature for proposing new species or subspecies. Khalif (2020) summarizes information available on the population in the eastern South Pacific, designates an identifiable specimen and type location, and provides a subspecies name. However, the subspecies description is incomplete and, importantly, is diagnosed by bibliographic references alone. This is minimally sufficient to make the name available (see Code, Art. 13.1.2), but no attempt seems to have been made to collect morphological or genetic evidence, despite the ready availability of a skull and nearly complete skeleton. This is poor practice and contrary to Recommendation 13A. We therefore regard the name B. musculus chilensis a nomen dubium and do not recognize it until these faults are remedied. Khalif (2021) also describes a new blue whale subspecies B. musculus arabica from the Arabian Sea. This work fails to acknowledge that more than one type of blue whale exists in northern Indian Ocean making it impossible to link the new blue whale song described by Cerchio et al. (2020) from this region to the blue whale skeleton from Kuwait. The subspecies is diagnosed only by bibliographic references to characterizations of its song and acoustics alone does not constitute sufficient evidence for taxonomic separation. We therefore regard the name B. musculus arabica a nomen dubium and do not recognize it.

The Bryde’s-like whales in the Gulf of Mexico have now been described as a new species of medium-sized balaenopterid, Balaenoptera ricei, by Rosel et al. (2021), with the common name Rice’s whale. The remaining Bryde’s whales are provisionally considered to comprise a single species, Balaenoptera edeni, following the usage of Kato and Perrin (2009) and Kershaw et al. (2013). However, Luksenburg et al. (2015) and Wada et al. (2003) accepted two species. Some workers recognize B. edeni as including only the small-form coastal Bryde’s whales of the western Pacific and Indian Oceans, using B. brydei for the globally distributed and larger, more oceanic form (Sasaki et al. 2006). Kato and Perrin (2009) and Kershaw et al. (2013) considered these more likely to be distinct at the subspecific level (although arguably at the species level), and they are included here provisionally as such. Balaenoptera omurai was described by Wada et al. (2003). It was previously confounded with the Bryde’s whale and has been confirmed as having a separate and ancient lineage (Sasaki et al. 2006).

To further resolve the taxonomy and systematics of all the medium-sized baleen whales (B. riceiB. edeni edeni, B. e. brydei, and including B. borealis) it is critical that a neotype be designated for B. brydei and that genetic data be obtained from that designated neotype.  In addition, genetic data should also be obtained from the holotype of B. edeni to validate the identity of museum specimens as well as samples collected from stranded and biopsied individuals. Finally, a comprehensive phylogenetic analysis using nuclear markers of all taxa in this complex with sufficient samples and range-wide geographic coverage is also needed.

Clarke (2004) proposed recognition of a pygmy form of the fin whale as a subspecies, based on distribution, size and coloration. He resurrected the synonym patachonica Burmeister, 1865 to apply to the subspecies: B. physalus patachonica. However, Pérez-Alvarez et al. (2021) conducted a phylogenetic analysis of fin whales and found no support for differentiation among Southern Hemisphere fin whales, recommending that the name patachonica Burmeister, 1865 be synonymized with B. physalus quoyi and the latter refer to all Southern Hemisphere fin whales. Archer et al. (2019) provided genetic evidence at both mitochondrial and nuclear genetic markers that fin whales in the North Pacific are significantly differentiated from those in the North Atlantic and the Southern Hemisphere. They proposed recognition of the North Pacific fin whale as a separate subspecies, B. physalus velifera.

Toothed Whales

In the odontocetes, Mesoplodon traversii (spade-toothed whale) was recognized as the senior synonym for M. bahamondi (Bahamonde’s beaked whale) (van Helden et al. 2002). The first complete specimen was recently described from a stranding on the North Island of New Zealand (Thompson et al. 2012). Mesoplodon perrini was described by Dalebout et al. (2002). Dalebout et al. (2014) resurrected Mesoplodon hotaula Deraniyagala, 1963, a species closely similar to M. ginkgodens. Using morphological and genomic evidence, Carrol et al. (2021) split M. mirus, identifying those in the Southern Hemisphere as M. eueu.

Yamada et al. (2019) provided morphological evidence, supported by genetic data (Morin et al. 2018, Kitamura et al. 2013), recognizing a new species of Berardius in the North Pacific, Berardius minimus.

The South Asian river dolphins (genus Platanista) have a long history of taxonomic revision, oscillating between being recognized as two species, Platanista gangetica (Lebeck, 1801) and P. minor Owen, 1853, and two subspecies of Platanista gangetica. The Taxonomy Committee, when it first created the taxonomy list, followed Rice’s (1998) treatment of Platanista and recognized a single species with two subspecies, Pggangetica and Pgminor. Recently, Braulik et al. (2014, 2021) have performed a morphological analysis of the two taxa, coupled with an analysis of mitochondrial DNA and recommended species-level status for the two subspecies. Individually, the support provided from these two lines of evidence was relatively weak: a single, but significant, diagnostic difference in the frontal bones of the skull, and five fixed differences and no shared mtDNA haplotypes, but a level of genetic divergence that does not exceed the species threshold identified by Taylor et al. (2017a). The combined evidence for diagnosability in the morphological and genetic lines of evidence, the significant difference in growth curves between the two taxa, and their estimated divergence time of ~0.55 million years, led the majority of committee members to accept the proposed elevation to species. However, the unavailability of samples from the upper reaches of the rivers where the two taxa may have last been in contact impedes a complete understanding of the evolutionary history of the two taxa and this posed some concern for a few members when evaluating the proposal to elevate the subspecies to species.

We recognize one species of Inia with two subspecies: I. geoffrensis geoffrensis (Blainville, 1817) and I. g. boliviensis (d’ Orbigny, 1834). I. g. boliviensis is found in the Bolivian Amazon basin and overlaps with other Inia in all morphological characters (da Silva, 1994; Ruiz-García et al. 2006). However, molecular genetic evidence from mitochondrial DNA (mtDNA) and nuclear introns (Banguera-Hinestroza et al. 2002; Ruiz-García et al. 2008) suggested these two subspecies are on separate evolutionary trajectories and deserve recognition as phylogenetic species. Hollatz et al. (2011) estimated that I. g. boliviensis has been reproductively isolated for 3.2 million years. However, these studies used geographically disparate samples, with a significant gap in sampling of Inia habitat between the Teotonio Rapids, hypothesized to be the barrier to gene flow for I. g. boliviensis, and the samples used to represent I. g. geoffrensis. Gravena et al. (2014), with much better sampling of the Madeira River system, including samples from immediately above and below the Teotonio Rapids, found that in fact these rapids did not appear to obstruct gene flow on an evolutionary scale. Thus, the conclusion that the Bolivian Inia above the Teotonio Rapids possessed unique mtDNA (a major line of evidence for recognizing species-level distinctness of I. boliviensis) was not supported by more extensive sampling (i.e., the initial appearance of separation was an artifact of poor sampling). Therefore, only the subspecies Inia geoffrensis boliviensis is retained, although given the newer evidence for a lack of isolation of the dolphins above the Teotonio Rapids (Gravena et al. 2014) and the lack of robust sampling, the strength for subspecies status is weakened. Another new species, Inia araguaiaensis, was described by Hrbek et al. (2014) from the Araguaia River, which is not connected to the Amazon and Siciliano et al. (2016) extended the known range of I. araguaiaensis further north to Marajó Bay, Brazil, through mtDNA analysis of three stranded specimens. Hrbek et al. (2014) only examined samples from two extremes of the distribution of Inia, so it is unclear if the molecular differences observed represented real species-level separation or were due to sampling from two locations separated by a large distance. Diagnostic osteological differences were also reported (Hrbek et al. 2014). However, because this study was based on the examination of very few specimens (only 2 for the new species and only 9 for I. geoffrensis) and did not account for effects of sexual dimorphism within the species, the authors’ conclusions are not convincing. In light of these arguments, the species here remains unlisted provisionally. Hrbek et al. (2014) did not recognize I. g. humboldtiana. Melo et al. (2021) examined acoustic evidence and found some suggestion of vocal differences, but vocalizations are known to be plastic in odontocetes. In addition, there was significant overlap in many of the measured parameters and classification based on the acoustic data exhibited an error rate near 30%, which is quite high for taxonomic decisions. Most recently, Cañizales (2020) and Emin-Lima et al. (2022) provide valuable new morphological data to evaluate aspects of the taxonomy within the genus Inia. Cañizales (2020) examined 20 skulls from Venezuela identified as representing I. g. humboldtiana and provided some evidence for differences between these samples and those of I. ggeoffrensis, but differences were slight, with overlap in several analyses. Emin-Lima et al. (2022) also focused on skull morphology and examined 46 skulls from distant locales within the Amazon basin and identified three morphological groups that largely corresponded with I. g. geoffrensisI. g. humboldtiana, and I. g. boliviensis.  They found no differences between I. g. geoffrensis and I. araguaiaensis. Resolution of the taxonomic status of all Inia forms requires an integrated approach using multiple lines of evidence, improved sampling throughout the distribution, and a thorough review of all the evidence (morphological, genetic, ecological, etc.). In addition, proposed changes to taxonomy will require a detailed taxonomic treatment, must provide diagnoses, and review relevant nomenclature. Some examples of recent species or subspecies descriptions and redescriptions providing the necessary taxonomic treatment can be seen at: Yamada et al. (2019), Braulik et al. (2021), Rosel et al. (2021), Costa et al. (2023).

We list the baiji Lipotes vexillifer as “possibly extinct” in conformance with the IUCN Red List, although extinction seems a certainty.

Previous editions of this list recognized two globally distributed species of common dolphins: the short-beaked common dolphin D. delphis and the long-beaked common dolphin D. capensis as proposed by Heyning and Perrin (1994)However, evidence that D. capensis thus considered is a polyphyletic taxon has been accumulating for some time. The long-beaked condition is apparently a convergent character state induced by regional ecology. In some regions, long-beaked common dolphins are genetically more closely related to short-beaked common dolphins than to long-beaked common dolphins in other regions (e.g., see Natoli et al. 2006). Cunha et al. (2015) summarized the relevant data and analyses, along with additional molecular data and analysis, and recommended that Delphinus capensis not be further used as proposed by Heyning and Perrin (1994). That recommendation is followed here. Cunha et al. (2015) noted that because the sympatric/parapatric long-beaked and short-beaked common dolphins off California in the eastern North Pacific (ENP) appear not to interbreed, perhaps the ENP long-beaked common dolphins might be recognized as a separate species D. bairdii Dall,1873 (as advocated by Banks and Brownell (1969) based on the long-beaked condition)However, the molecular analysis for the ENP (Rosel et al. 1994) did not include common dolphins from the contiguous regions to the south in the eastern tropical and eastern South Pacific. Jefferson et al. (2024) reviewed the taxonomic status of the long-beaked and short-beaked common dolphin forms in the eastern Pacific using genetic data based on mtDNA (fragments of the control region and cytochrome b) and cranial morphometrics. Samples (classified a priori whenever possible to short- or long-beaked based on photographic records or geographic location) were collected from eastern North Pacific, Gulf of California, eastern tropical Pacific and eastern South Pacific. Additional information on external morphology, color pattern and life history were also obtained through a literature review. Diagnosability based on skull morphometrics was obtained for both forms in the eastern Pacific, whereas mtDNA data separated both forms with high level of differentiation but there was evidence for shared mitochondrial haplotypes. Based on all the evidence presented, the authors suggested full species status for both forms in the eastern Pacific, with D. bairdii found along the eastern Pacific, but with a distributional gap in the eastern tropical Pacific. While a majority of committee members believe there are evident distinctions between both long-beaked and short-beaked forms in the eastern North Pacific as highlighted by Jefferson et al. (2024), a 2/3 majority of voting members was not reached to elevate them to full species. Primary concerns to the changes focused on the lack of reciprocal monophyly in mitochondrial DNA data, and a lack of nuclear DNA evidence for separation.  It was noted that what nuclear data are available (Kingston et al. 2009) did not separate the two forms.  Nuclear DNA evidence is essential to better understand male-mediated gene flow, especially when considering the convergent character of the long-beaked in Delphinus. Further study focusing on nuclear DNA is needed to better solve remaining uncertainties in some relationships among short- and long-beaked common dolphins within the Pacific Ocean and on a more global scale. Therefore, pending a more complete global review and revision of the common dolphins, the long-beaked ENP form is still considered here provisionally as a subspecies D. delphis bairdii following the usage of Hershkovitz (1966)4Delphinus capensis Gray, 1828 from South Africa remains in the synonymy of Delphinus delphis Linnaeus, 1758. The long-beaked common dolphin of the Indian Ocean is retained as a subspecies D. delphis tropicalis. Recognition of the Black Sea common dolphin, D. d. ponticus Barabash, 1935, is well-recognized by molecular genetic data (Natoli et al. 2008).

The genus Lagenorhynchus is widely considered a polyphyletic taxon containing morphologically convergent species (Cipriano 1997, LeDuc et al. 1999, McGowen 2011, Banguera-Hinestroza et al. 2014, Vollmer et al. 2019). Vollmer et al. (2019) provided a detailed review of the relationships among members of the genus Lagenorhynchus and their relationship to Cephalorhynchus and Lissodelphis. Results continue to support the polyphyletic nature of the genus Lagenorhynchus and multiple morphological and genetic analyses indicate that Lalbirostris and Lacutus are evolutionarily distinct from the other members of all three genera. Vollmer et al. (2019) recommended revision of the genus sensu Leduc et al. (1999), placing L. obscurusLobliquidensL. australis and Lcruciger into the genus Sagmatias, L. acutus into the genus Leucopleurus and leaving L. albirostris in a monotypic genus Lagenorhynchus. While a majority of committee members supported the changes proposed by Vollmer et al. (2019), a 2/3 majority of voting members was not reached. Primary objection to the changes focused on remaining uncertainties in some relationships and the potential confusion that may be created if the proposed changes require further revision in the near future. At issue are 1) the conflicting support among data sets for a sister-taxa relationship between Lalbirostris and L. acutus (which would obviate the need for Leucopleurus), and 2) evidence that australis and cruciger should be included in Cephalorhynchus (which would necessitate a new genus for obliquidens and obscurus, as australis is the type species for the genus Sagmatias). Therefore, the taxonomy list retains all species in Lagenorhynchus, recognizing that the current taxonomy does not reflect the evolutionary distinctiveness of Lalbirostris and Lacutus. Next steps in unraveling the taxonomy of these dolphins will need to involve robust datasets that include all Lagenorhynchus and Cephalorhynchus species. Harlin-Cognato (2010) recognized L. obscurus posidonia (Peru/Chile).

The Irrawaddy dolphin was split into O. brevirostris and O. heinsohni, the Australian snubfin dolphin (Beasley et al. 2005).

Based on genetic, morphological and ecological data, Morin et al. (2024) provided a taxonomic revision for two ecotypes of Orcinus orca in the eastern North Pacific: Bigg’s killer whale (also known as transient ecotype) and the resident killer whale. The level of differentiation observed led the authors to recommend their recognition as distinct species: O. rectipinnus (Bigg’s killer whale) and O. ater (resident killer whale). Although the majority of the voting members recognize the high level of differentiation between the two ecotypes in all the evidence presented in Morin et al. (2024), there was uncertainty whether this diagnosability represented species- or subspecies-level designation. Some points argued against species designation at the time included: 1) the nesting of both clades within the wider O. orca clade in the mitogenome phylogeny; 2) presence of episodic gene flow among the ecotypes, which needs further investigation; and 3) the need to conduct a more comprehensive analysis on a global context to better understand how distinct these two ecotypes are from other Orcinus orca clades, including those found at latitudes below ~34º N off the coasts of California and Mexico and the more northerly Bigg’s and offshore ecotypes, which were not evaluated in the paper. Previously, the Committee followed the recognition in Krahn et al. (2004) of two un-named subspecies of killer whales for the eastern North Pacific, which were listed in previous version of the List of Proposed Un-named Species and Subspecies. These two un-named subspecies correspond to the resident and Bigg’s/transient ecotypes, respectively. Therefore, pending a more complete global review and revision of the killer whales, the two ecotypes are considered here provisionally as distinct subspecies of Orcinus orca and named following Morin et al. (2024): O. orca ater (resident killer whale) and O. orca rectipinnus (Bigg’s killer whale), with O. orca orca (common killer whale) as the nominate subspecies.5

Based on a combined analysis of molecular genetic and morphological data, Mendez et al. (2013) proposed recognizing four species of Sousa (the humpback dolphins): the previously here-listed S. teuszii and S. chinensis plus S. plumbea and a new un-named species from the waters of northern Australia that was originally proposed by Frère et al. (2008, 2011) based on molecular data. A drawback of the phylogenetic analyses by Mendez et al. (2013) is that there was only one sample from the area of supposed sympatry of S. plumbea and S. chinensis and very low coverage of the Indo-Malay region (n=5). The two species are listed here provisionally, pending the outcome of further analysis including more samples from those areas. The new species from Australia has been given the name Sousa sahulensis (Jefferson and Rosenbaum 2014). The new subspecies Sousa chinensis taiwanensis was described by Wang et al. (2015).

It has been noted repeatedly, most recently by Perrin et al. (2013), that the delphinine genera Stenella and Tursiops are paraphyletic and that at present there is no molecular or morphological basis for satisfactory resolution of phylogenetic relationships in the subfamily. A possible solution would be to return all the species in TursiopsSousa, and Stenella to Delphinus, the genus in which they were first described, and place Lagenodelphis hosei there as well. However, considering that this would obscure the clear close relationship of the present Sousa and Tursiops species, the status quo is maintained here provisionally, pending the outcome of more definitive morphological and molecular studies. Eventually a more natural classification will emerge.

Perrin et al. (1999) established the subspecies Stenella longirostris roseiventris.

The Burrunan dolphin Tursiops australis, described by Charlton-Robb et al. (2011), is not included here; its basis is questionable because of several potential problems: 1) the specimens were compared morphologically only with bottlenose dolphins from Australia; 2) despite the small sample sizes, the series overlapped in all metric characters and separation was possible only with multivariate analysis (which commonly resolves geographical forms within a species, e.g., see Perrin et al. (1999) and Perrin et al. (2011) for Stenella longirostris and Tursiops truncatus, respectively); 3) comparisons of external morphology and non-metric characters were made only with T. truncatus, to the exclusion of T. aduncus; and 4) support for important nodes in molecular trees suggesting phylogenetic separation was low. A rigorous re-evaluation of the relevant data and arguments is needed. Recently, Jedensjö et al. (2020) conducted a broader morphological comparison of Tursiops skulls from around Australia, including skulls of both Ttruncatus and Taduncus and their respective holotypes, and did not find support for the Burrunan bottlenose dolphin, Taustralis, proposed by Charlton-Robb et al. (2011). Skulls previously classified as Taustralis all fell well within the Ttruncatus group. In contrast, Moura et al. (2020) placed Taustralis within a Taduncus clade based on a nuclear genetic phylogeny.

Based on morphological and genetic analyses, Costa et al. (2022) described a new species of Tursiops from the western North Atlantic, separating the long-recognized coastal and offshore morphotypes from the western North Atlantic into two species. The offshore morphotype remains Tursiops truncatus, while the coastal morphotype found in nearshore coastal waters as well as the bays and estuaries along the U.S. east coast was split out as the new species Terebennus (Cope, 1865)Additional work is needed to identify the full geographic distribution of Terebennus in the Gulf of Mexico and Caribbean.

Costa et al. (2023) evaluated morphological variation among three distinct morphotypes of T. truncatus in the eastern Pacific, the southern California/Mexico coastal form, the northern temperate offshore form, and an eastern tropical Pacific (ETP) offshore form. Cranial morphology and body size separate the eastern tropical Pacific (ETP) offshore form from other Pacific Tursiops. The authors resurrected the name Ttnuuanu Andrews, 1911 for this subspecies. Another subspecies is recognized for the Black Sea, the Black Sea bottlenose dolphin, T. t. ponticus Barabash-Nikiforov, 1940, which is now well-supported by molecular genetic data (Viaud-Martinez et al. 2008).

Costa et al. (2016), Wickert et al. (2016), and Hohl et al. (2020) have examined morphological characteristics of Tursiops specimens from the western South Atlantic. Costa et. al. (2016) recommended subspecies status for the larger coastal form found between southern Brazil and northern Argentina, while both Wickert et al. (2016) and Hohl et al. (2020) have recommended species status. Costa et al. (2021) paired morphological and genetic data from samples collected from both forms in southern Brazil and found strong congruence between morphological and mitochondrial and nuclear divergence; genetic differentiation was also observed in Oliveira et al. (2019). In both genetic studies, however, evidence for shared mitochondrial haplotypes and possibly shared nuclear ancestry was found. We provisionally recognize the subspecies T. t. gephyreus Lahille 1908 (Lahille’s bottlenose dolphin) for this larger coastal form. Improved geographic sampling and improved objectivity in hypothesis testing is needed to fully resolve the taxonomy of Tursiops in this region. In particular, further work is needed to better identify the distribution of the gephyreus form and determine its phylogenetic relationship to coastal and offshore Tursiops in the western North Atlantic and throughout Caribbean waters. Wang et al. (2021) showed gephyreus to be the correct trivial name for this taxon (as long as it continues to be recognized as a subspecies or species).

Kinze (2018) proposed that the scientific name for Tursiops truncatus should be Tursiops tursio as tursio has priority over truncatus. The committee noted that resurrecting the name Ttursio for the bottlenose dolphin would upset long-standing usage and would cause considerable confusion in national and international treaties, agreements, etc. Therefore, the name Ttruncatus should continue to be used for the common bottlenose dolphin to maintain stability.

Wang et al. (2008) and Jefferson and Wang (2011) established Neophocaena asiaeorientalis as a full species distinct from the Nphocaenoides, with two subspecies. Zhou et al. (2018) examined genomic DNA sequence data and concluded that there was significant genetic differentiation between the two subspecies of Nasiaeorientalis, including evidence for genetic adaptation to the freshwater environment of the Yangtze River. The authors proposed the two subspecies of Nasiaeorientalis be elevated to species-level, the Yangtze finless porpoise, Nasiaeorientalis Pilleri and Gihr 1927, and the East Asian finless porpoise, Nsunameri Pilleri and Gihr 1972. However, there were no samples in this study from near the mouth of the Yangtze River where the marine and river subspecies could possibly be sympatric and where genetic interchange could occur. While the results of the study are consistent with recently diverged taxa, the lack of samples in the potential area of sympatry make it difficult to rule out an isolation by distance effect.

Viaud-Martinez et al. (2007) concluded based on morphological and molecular genetic evidence that Phocoena phocoena relicta is a distinct subspecies.

Manatees and Dugongs

In the Sirenia, subspecies of the dugong are not currently recognized (Domning, 1996; see for update to 1996 publication). However, no in-depth study has been undertaken to address the issue of subspecies.


Footnotes (dissenting opinions):

1 The full authority is: Carroll, McGowen, McCarthy, Marx, Aguilar, Dalebout, Dreyer, Gaggiotti, Hansen, van Helden, Onoufriou, Baird, Baker, Berrow, Cholewiak, Claridge, Constantine, Davison, Eira, Fordyce, Gatesy, Greg Hofmeyr, Martín, Mead, Mignucci-Giannoni, Morin, Reyes, Rogan, Rosso, Silva, Springer, Steel and Tange Olsen, 2021.

2 Use of Order Cetartiodactyla (artiodactyls and cetaceans) is favored by most evolutionary mammalogists working with molecular data. Some others, including many marine mammalogists and paleontologists, favor retention of Order Cetacea in the interest of taxonomic stability, despite rendering the retained Order Artiodactyla paraphyletic.

3 (from D. Rice) Baker et al. (2003) hold that there is no evidence that would support the classification of the right whales as more than a single biological species. [The three species are here recognized as phylogenetic species.]

4 (from T. Jefferson) The List should retain the eastern North Pacific (ENP) long-beaked common dolphin as a separate species of DelphinusD. bairdii (as in Banks and Brownell 1969). The evidence for species status is published and is considerable, especially the molecular differences. Notwithstanding issues related to poor sampling from areas of potential sympatry further south, the balance of the evidence seems to support a lack of interbreeding throughout a very large region of overlap, along with clear ecological differences (see Jefferson et al. 2024). In this view, the error by Heyning and Perrin (1994) was not in splitting out the ENP long-beaked common dolphins as a distinct species, but in assuming that the name D. capensis applied there and that all long-beaked populations of Delphinus belonged to D. capensis.

5 One member (RLB) does not agree with the practice of the Committee to make subspecies out of newly described species if they are not accepted by 2/3 of the group. These species were properly described should stand as new species until they are reviewed by the next reviser of the species or species within these genera (Orcinus and Delphinus). The Committee has no official capacity to create new taxa as they have done now with Orcinus and Delphinus.



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Last updated June 2024 by members of the Committee on Taxonomy:

  • Ana P. Costa (Chair)
  • Frederick I. Archer
  • Scott Baker
  • Daryl J. Boness
  • Robert L. Brownell, Jr.
  • Morgan Churchill
  • Daryl P. Domning
  • Thomas A. Jefferson
  • Carl Kinze
  • Michael McGowen
  • Larissa R. Oliveira
  • Patricia E. Rosel
  • John Y. Wang
  • Tadasu K. Yamada

6 comments on List of Marine Mammal Species and Subspecies

  • Michael Fontaine

    Dear Committee,

    We would like to bring to your attention our recent work on the harbour porpoises in the southern part of the NE Atlantic distribution range of the harbour porpoises (Fontaine et al. 2014 and Fontaine 2016). In these studies, we provide compelling evidence that harbour porpoises from the Iberian and Mauritanian waters are 2 differentiated populations of a distinct ecotype inhabiting the upwelling waters off Iberia and Mauritania. Morphological, ecological and genetic differentiation are now compelling. The genetic divergence between the Iberian and Mauritanian porpoises and the northern populations living on the European continental shelf north of the Bay of Biscay is as large as the genetic divergence reported between the Black Sea population and the populations north of the Bay of Biscay. We also reconstructed the evolutionary history of these populations and showed that the Iberian-Mauritania and the Black Sea populations descend from a common ancestor now extinct which occurred in the Mediterranean Sea during the LGM.

    Given this level of divergence combined with other evidence of morphological and ecological differentiation, Fontaine et al. (2014) proposed that the southern porpoises from Iberia and Northwest Africa were a distinct ecotype and separate Evolutionary Significant Units (Moritz 2002) from the porpoises inhabiting the continental shelf from the north side of the Bay of Biscay to the subarctic waters of Norway and Iceland. As such, the authors suggested that porpoises from Iberia and Mauritania should be raised to the level of subspecies, at the same taxonomic level as the porpoises from the Black Sea. We have suggested a new sub-species name for those meridional NE Atlantic porpoise (Phocoena phocoena meridionalis). We thus ask that the committee examine our proposal and provide an official status for those porpoises. Such recognition is timely given the very small size reported for the Iberian porpoises, and the status of the Mauritanian porpoises is unknown. Therefore, having a proper taxonomic definition is paramount for the conservation of this species and its independent ESU’s.

    Thank you to consider our request
    Best Regards
    Michael C Fontaine


    Fontaine M. C., 2016 Harbour Porpoises, Phocoena phocoena, in the Mediterranean Sea and Adjacent Regions: Biogeographic Relicts of the Last Glacial Period. Mediteranean Marine Mammal Ecology and Conservation (Notarbartolo di Sciara G, Podestà M, Curry BE, Eds.), Adv. Mar. Biol. 75: 333–358.

    Fontaine M. C., Roland K., Calves I., Austerlitz F., Palstra F. P., Tolley K. A., Ryan S., Ferreira M., Jauniaux T., Llavona Á., Öztürk B., Oztürk A. A., Ridoux V., Rogan E., Sequeira M., Siebert U., Vikingsson G. A., Borrell A., Michaux J. R., Aguilar A., 2014 Postglacial climate changes and rise of three ecotypes of harbour porpoises, Phocoena phocoena, in western Palearctic waters. Mol. Ecol. 23: 3306–3321.

  • Patricia Rosel

    Hello Michael,
    Thank you for your post and the information you provided. The Committee has this topic on the agenda for its next discussion and update. We update the list once per year. The next update will be in Spring 2017.

    Best regards,
    Patty Rosel
    Chair, Committee on Taxonomy

  • Giuseppe Notarbartolo-di-Sciara

    Dear Committee,

    I believe that Phoca vitulina (and P. v. vitulina) should be followed by the author name and year without parentheses, since the species was listed as such in Linnaeus’ original writing.

    Considering the very high value of this list as reference for anything related to marine mammal taxonomy, in order to make it even more valuable it is important that mistakes be identified (with the help of everyone) and corrected as soon as possible.

    Thank you and best wishes,

  • Patricia Rosel

    Dear Giuseppe,
    Thank you for bringing this to our attention. The Committee will be meeting this spring and we will make corrections in the next update.

    Best regards,
    Patty Rosel

  • Randall Reeves

    I see in the current draft 2021 NOAA Stock Assessment report for the
    Eastern North Pacific Southern Resident Stock of killer whales that the resident and transient ecoytypes “are currently listed as unnamed subspecies…
    (Committee on Taxonomy 2018)” based on Morin et al. (2010). However, no subspecies are shown on the current online list (Committee on Taxonomy 2021). What am I missing?

  • Manuel E. dos Santos

    Manuel E. dos Santos

    Dear Colleagues,

    Although I am no expert on taxonomy or mustelids, I would like to ask for your views regarding the otter species that are left out of the List.

    Presenting this List as the most reasoned inventory of “marine mammal” biodiversity, I happily explain to my students that, because of phylogenetic proximity, several non-marine species are included (e.g., Inia geoffrensis, Sotalia fluviatilis, Platanista gangetica, Trichechus inunguis, Pusa sibirica).

    Well, by the same criteria, should the List not include at least some of the river otters (e.g., the giant otter, Pteronura brasiliensis, or the Neotropical otter, Lontra longicaudis)? I understand these animals use terrestrial dens and spend time on more amphibious activities, but so do also the polar bear and various pinnipeds. I feel there is this apparent logical imbalance in the List, and I ask if you could be so kind as to clarify.

    Thank you for your time and attention, and for the great work of the Committee.


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