Mormyrinae

Mormyrinae
The Peters' elephantnose fish, Gnathonemus petersii, has the largest brain-to-body weight ratio of all known vertebrates.[1]
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Osteoglossiformes
Family: Mormyridae
Subfamily: Mormyrinae
Genera

see text

The subfamily Mormyrinae contains all but one of the genera of the African freshwater fish family Mormyridae in the order Osteoglossiformes. They are often called elephantfish due to a long protrusion below their mouths used to detect buried invertebrates that is suggestive of a tusk or trunk (some such as Marcusenius senegalensis gracilis are sometimes called trunkfish though this term is usually associated with an unrelated group of fish). They can also be called tapirfish.

Fish in this subfamily have a high brain to body mass ratio due to an expanded cerebellum (called a gigantocerebellum) used in their electroperception.[2] Linked to this they are notable for holding the zoological record at around 60% as the brains that consume the most energy as a percentage of the body's metabolic rate of any animal.[1] Previous to this discovery, it was the “human brain, which had been thought to hold the record in this respect”.[1]p. 605 The human brain in comparison uses only 20%.[3]

Mormyrinae is the largest subfamily in the Osteoglossiformes order with around 170 species.

  1. ^ a b c Nilsson G (1996) "Brain and body oxygen requirements of Gnathonemus petersii, a fish with an exceptionally large brain" Journal of Experimental Biology, 199(3): 603-607. Download
  2. ^ Bell CC, Szabo T (1986). Electroreception in Mormyrid fish. Central Anatomy. pp. 375–421. In: Bullock TH, Heiligenberg W, (eds.), Electroreception. New York, Wiley ISBN 978-0-387-23192-1
  3. ^ Mink JW, Blumenschine RJ, Adams DB. (1981). Ratio of central nervous system to body metabolism in vertebrates: its constancy and functional basis. Am J Physiol. 241(3):R203-12. PMID 7282965