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Hippopotamus (Hippopotamus amphibius) & Pygmy Hippopotamus (Choerpsis liberiensis) Fact Sheet: Taxonomy & History

Taxonomy and Nomenclature

  • Scientific name
    • Hippopotamus: hippos from Greek for horse, potamos from Greek for "river or rushing water"
    • Choeropsis: from the Greek for "having the appearance of a young pig" (Parker 2010)
  • Common name (for Common or River Hippo)
    • Common Hippopotamus, River Hippopotamus, or Nile Hippopotamus; In Afrikaans: seekoei (sea cow).
    • Numerous tribal names including: Kiboko (Kiswahlili), Olmakau (Masai), Jir (Somali).
    • German: Nilpferd (Nile horse)
    • Spanish: Hipopotamos
    • French: Hippopotame
  • Pygmy Hippos have recently had their taxonomy and phylogeny reassessed (Boisserie & Kingdon 2005)
    • Correct scientific name for the genus should be Choeropsis
    • Commonly used Hexaprotodon now applies only to extinct hippos

Evolutionary History

  • Closest living relatives to hippos are whales (Boisserie et al 2005)
    • To reflect this close relationship, families of whales and families of artiodactyls should be grouped together
    • The new taxonomic Order, Cetartiodactyla, reflects both numerous DNA and fossil studies
  • Pigs (Tayassuidae) are not close relatives of hippos, contrary to many taxonomies based on morphology. (Boisserie et al 2005)
  • Oldest Cetartiodactyla fossils are members of the family Anthracotheriidae from Asia dating to around 41 million years ago (Eocene).
    • Anthracotheres diversified to Africa in Eocene times.
  • By Miocene times (around 15.7 million years ago), the earliest hippos probably arose from Anthracotheres. (Lihoreau et al 2006)
    (Behrensmeyer et al 2002) (Boisserie et al 2005)
    • Anthracotheres + hippos most likely form a sister taxa to whales
    • Share a common ancestor with whales
  • Earliest hippos lived in Africa (Harris et al. 2008)
  • Fossil hippos from Pliocene and Pleistocene times are numerous and diverse. (Harris et al. 2008)
    • By Ice Age Pleistocene times (1.8 million to 13,000 years ago) hippos inhabited England and Europe, Asia, and Africa.
    • Pollen studies show that the hippos were associated with swamp forests along riverbanks. (Ravazzi et al 2009)
  • Around 3500 B.C., hippos were apparently maintained in a private zoo along with elephants and baboons in the ancient Egyptian city of Hierakonpolis. (Rose 2010)
  • Extinct dwarf hippo remains found in Madagascar and Cyprus; date to 1,000 years ago, or less.
    (MacPhee & Flemming 1999) (Stuenes 1989)
    • May have been hunted to extinction by humans. (MacPhee & Burney 1991)
    • Two extinct dwarf species on Madagascar had similar ecological specializations as living Pygmy and
      Common Hippo today: one more aquatic, one more terrestrial
    • Hippos arrived in Madagascar presumably by rafting across the ocean between this island and Africa.

Classification

Kingdom: Animalia

Phylum: Chordata

Class: Mammalia

Order: Artiodacyla* (even-toed hoofed animals: includes pigs, sheep goats, cattle, deer)

Family: Hippopotamidae

Genus: Hippopotamus

Species: Hippopotamus amphibius - common hippopotamus

Genus: Choeropsis

Species: Choeropsis liberiensis - pygmy hippopotamus

*Anatomical and DNA evidence on the relationship between Artiodactyla (even-toed ungulates) and Cetacea (whales and dolphins) led to a merging of the two orders into a new group, Cetartiodactyla (Montgelard, 1997; reviewed in Kulemzina, 2009). As of October 2012, experts had not agreed on whether to define Cetartiodactyla as an official taxonomic order that would replace Artiodactyla and Cetacea. Some continue to list hippopotamuses in the order Artiodactyla (Franklin, 2011) or use the term Cetartiodactyla without defining it as an order (IUCN, 2008).


Describer (Date): Linnaeus (1758) Systema Naturae Tenth ed. Vol 1. p 74, Laurentii Salvii Stockholm. Described animals from the Nile River in Egypt.

Page Citations

Boisserie (2008)
Boisserie et al. (2005)
Harris et al. (2008) 
Kingdon (1979)
Lihoreau et al. (2006)
Meester & Setzer (1971)
Stuenes (1989)
Wilson & Reeder (1992)

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