Mediterranean monk seal Monachus monachus, copyright MoM.

Belongs within: Carnivora.
Contains: Phocinae.

The Phocidae, true seals, are one of the two lineages within the Pinnipedia. In contrast to the eared seals of the Otarioidea, phocids lack external ear flaps, and are unable to bring the hind flippers underneath the body for walking on land. Living phocids are divided between the subfamilies Phocinae and Monachinae; Monachinae are more diverse in the Southern Hemisphere, being represented in the Northern Hemisphere by the monk seals Monachus and the northern elephant seal Mirounga angustirostris. The elephant seals Mirounga are the largest living carnivorans with the largest individuals reaching weights of about four tonnes.

See also: Taxon of the Week: Phocidae.

Synapomorphies (from Tedford 1976): Aquatic, swimming mainly by flexion of trunk; dentition reduced to homodonty; enlarged teres process for teres major muscle which occupies its lateral border.

<==Phocidae [Cystophorinae]
    |  i. s.: Palmidophoca Ginsburg & Janvier 1975 SM93
    |           `--P. callirhoe Ginsburg & Janvier 1975 BDR85
    |         Praepusa Kretzoi 1941 SM93
    |           `--P. pannonica G76
    |         Monachopsis Kretzoi 1941 SM93
    |         Properiptychus Ameghino 1897 SM93
    |--Semantorinae [Semantoridae] T76
    |    |--Semantor T76
    |    `--Potamotherium Geoffroy 1833 T76, D07
    |         `--P. valetoni G76
    `--+--Phocinae AG06
       `--Monachinae [Lobodontinae] AG06
            |  i. s.: Monotherium Van Beneden 1876 R76, SM93
            |           |--M. aberratum R76
            |           |--M. affine R76
            |           |--M. delognii R76
            |           |--M. gaudini R76
            |           |--M. maeoticum [=Phoca maeotica] R76
            |           `--M. wymani R76
            |         Pliophoca etrusca R76
            |         Piscophoca pacifica de Muizon 1981 BDR85
            |         Callophoca R76
            |           |--C. ambigua [=Mesotaria ambigua] R76
            |           `--C. obscura R76
            |         Pristiphoca occitana R76
            |         Properiptychus argentinus Ameghino 1893 BDR85
            |--+--Messiphoca mauretanica de Muizon 1981 BDR85
            |  `--Monachus Fleming 1822 FS15, BR05 [Monachini]
            |       |--M. monachus FS15
            |       `--+--M. schauinslandi FS15
            |          `--M. tropicalis FS15
            `--+--Mirounga Gray in Griffith 1827 FS15, C57 (see below for synonymy)
               |    |--M. leonina (Linnaeus 1758) (see below for synonymy) C57
               |    `--M. angustirostris FS15
               `--Lobodontini AG06
                    |--Ommatophoca Gray 1844 FS15, C57
                    |    `--*O. rossii Gray 1844 C57
                    `--+--+--Lobodon Gray 1844 FS15, C57
                       |  |    `--*L. carcinophagus (Jacquinot & Pucheran 1842) (see below for synonymy) C57
                       |  `--Homiphoca de Muizon & Hendley 1980 BDR85
                       |       `--*H. capensis (Hendey & Repenning 1972) [=Prionodelphis capensis] BDR85
                       `--+--Leptonychotes Gill 1872 FS15, C57 [incl. Poecilophoca Flower & Lydekker 1891 C57]
                          |    `--*L. weddellii (Lesson 1826) (see below for synonymy) C57
                          `--+--Acrophoca de Muizon 1981 BDR85, D07
                             |    `--A. longirostris de Muizon 1981 BDR85
                             `--Hydrurga Gistel 1848 FS15, C57 (see below for synonymy)
                                  `--*H. leptonyx (Blainville 1820) (see below for synonymy) C57

Inorganic: Mirounga leconina minilorientalis Okamura 1987 O87
           Monachus schauinslandi protominilorientalus Okamura 1987 O87

Hydrurga Gistel 1848 FS15, C57 [incl. Ogmorhinus Peters 1875 C57, Stenorhynchotes Turner 1888 C57]

*Hydrurga leptonyx (Blainville 1820) [=Phoca leptonyx, Ogmorhinus leptonyx, Ogmorhynus leptonyx, Stenorhincus leptonyx, Stenorhynchus leptonyx; incl. Phoca homei Lesson 1828] C57

*Leptonychotes weddellii (Lesson 1826) [=Otaria weddellii, Leptonix weddelii, Leptonyx weddellii, Phoca weddelii, Phoca weddellii, Poecilophoca weddelli, Stenorhynchus weddellii; incl. Phoca leopardina Hamilton Smith 1839, Leptonyx leopardinus] C57

*Lobodon carcinophagus (Jacquinot & Pucheran 1842) [=Phoca carcinophaga, L. carcinophaga, Ogmorhinus carcinophagus, Stenorhynchus carcinophagus; incl. S. serridens Owen 1843] C57

Mirounga Gray in Griffith 1827 FS15, C57 [=Morunga Gray 1843 C57; incl. Macrorhinus Cuvier 1826 non Latreille 1825 C57, Macrorhyna (l. c.) C57, Physorhinus Gloger 1841 non Esch. 1836 C57, Rhinophoca Wagler 1830 C57; Miroungini]

Mirounga leonina (Linnaeus 1758) [=Phoca leonina, Macrorhinus leoninus; incl. P. ansonii Desmarest 1820, Ma. ansonii, Mirounga ansonii, Phoca coxii Desmarest 1820, Macrorhinus coxii, Ma. leoninus crosetensis Lydekker 1909, Phoca dubia Fischer 1829, P. elephantina Molina 1782, Cystophora elephantina, Macrorhinus elefantinus, Morunga elephantina, Cystophora falklandica Peters 1875, Macrorhinus leoninus flaclandicus, C. kerguelensis Peters 1875, Ma. leoninus macquariensis Lydekker 1909, Mirounga patagonica Gray 1827, Phoca proboscidea Péron 1817, Cystophora proboscidea, Macrorhinus proboscideus, *Mirounga proboscidea, Phoca resima Péron 1817, Macrorhinus leoninus typicus Lydekker 1909] C57

*Type species of generic name indicated


[AG06] Arnason, U., A. Gullberg, A. Janke, M. Kullberg, N. Lehman, E. A. Petrov & R. Väinölä. 2006. Pinniped phylogeny and a new hypothesis for their origin and dispersal. Molecular Phylogenetics and Evolution 41 (2): 345–354.

[BDR85] Barnes, L. G., D. P. Domning & C. E. Ray. 1985. Status of studies on fossil marine mammals. Marine Mammal Science 1 (1): 15–53.

[BR05] Bouchet, P., & J.-P. Rocroi. 2005. Classification and nomenclator of gastropod families. Malacologia 47 (1–2): 1–397.

[C57] Cabrera, A. 1957. Catalogo de los mamiferos de America del Sur. I (Metatheria—Unguiculata—Carnivora). Revista del Museo Argentino de Ciencias Naturales “Bernardino Rivadavia” e Instituto Nacional de Investigacion de Las Ciencias Naturales, Ciencias Zoológicas 4 (1): 1–307.

[D07] Dixon, D. 2007. The Complete Illustrated Encyclopedia of Dinosaurs & Prehistoric Creatures. Hermes House: London.

[FS15] Faurby, S., & J.-C. Svenning. 2015. A species-level phylogeny of all extant and late Quaternary extinct mammals using a novel heuristic-hierarchical Bayesian approach. Molecular Phylogenetics and Evolution 84: 14–26.

[G76] Grigorescu, D. 1976. Paratethyan seals. Systematic Zoology 25 (4): 407–419.

[O87] Okamura, C. 1987. New facts: Homo and all Vertebrata were born simultaneously in the former Paleozoic in Japan. Original Report of the Okamura Fossil Laboratory 15: 347–573.

[R76] Ray, C. E. 1976. Geography of phocid evolution. Systematic Zoology 25 (4): 391–406.

[SM93] Stucky, R. K., & M. C. McKenna. 1993. Mammalia. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 739–771. Chapman & Hall: London.

[T76] Tedford, R. H. 1976. Relationship of pinnipeds to other carnivores (Mammalia). Systematic Zoology 25 (4): 363–374.

Last updated: 9 February 2022.


  1. Surely "Aquatic" is plesiomorphic?

  2. Well, Tedford was one of those who supported a diphyletic Pinnipedia. I think a homodont dentition might also be characteristic of Pinnipedia as a whole, not just phocids.

    I could also try and weasel out of it by saying that I'd referred to 'synapomorphies', not 'autapomorphies' :-P


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