Salmonidae

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Salmonidae
Temporal range: Upper Cretaceous–Recent
[1]
Chinook salmon (Oncorhynchus tschawytscha)
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Infraclass: Teleostei
Superorder: Protacanthopterygii
Order: Salmoniformes
Bleeker, 1859
Family: Salmonidae
G. Cuvier, 1816
Genera
(see text)

Salmonidae is a family of ray-finned fish, the only living family currently placed in the order Salmoniformes. It includes salmon, trout, chars, freshwater whitefishes and graylings. The Atlantic salmon and trout of the genus Salmo give the family and order their names.

Salmonids have a relatively primitive appearance among the teleost fish, with the pelvic fins being placed far back, and an adipose fin towards the rear of the back. They are slender fish, with rounded scales and forked tails. Their mouths contain a single row of sharp teeth.[2] Although the smallest species is just 13 centimetres (5.1 in) long as an adult, most are much larger, with the largest reaching 2 metres (6.6 ft).[1]

All salmonids spawn in fresh water, but in many cases the fish spend most of their lives at sea, returning to the rivers only to reproduce. This life cycle is described as anadromous. They are predators, feeding on small crustaceans, aquatic insects, and smaller fish.[2]

Evolution[edit]

Current salmonids arose from three lineages: whitefish (Coregoninae), graylings (Thymallinae), and the char, trout and salmons (Salmonidae). Generally, all three lineages are accepted to share a suite of derived traits indicating a monophyletic group.[3]

Salmonidae first appear in the fossil record in the middle Eocene with the fossil Eosalmo driftwoodensis, which was first described from fossils found at Driftwood Creek, central British Columbia. This genus shares traits found in the Salmoninae, whitefish and grayling lineages. Hence, E. driftwoodensis is an archaic salmonid, representing an important stage in salmonid evolution.[3]

A gap appears in the salmonine fossil record after E. driftwoodensis until about seven million years ago (mya), in the late Miocene, when trout-like fossils appear in Idaho, in the Clarkia Lake beds.[4] Several of these species appear to be Oncorhynchus—the current genus for Pacific salmon and some trout. The presence of these species so far inland established that Oncorhynchus was not only present in the Pacific drainages before the beginning of the Pliocene (~5–6 mya), but also that rainbow and cutthroat trout, and Pacific salmon lineages had diverged before the beginning of the Pliocene. Consequently, the split between Oncorhynchus and Salmo (Atlantic salmon) must have occurred well before the Pliocene. Suggestions have gone back as far as the early Miocene (~20 mya).[3][5]

Classification[edit]

Together with the closely related Esociformes (the pikes and related fishes), Osmeriformes (e.g. smelts) and Argentiniformes, the Salmoniformes comprise the superorder Protacanthopterygii.

The Salmonidae (and Salmoniformes) are divided into three subfamilies and around ten genera:[1]

Order Salmoniformes

Timeline of genera[edit]

Quaternary Neogene Paleogene Cretaceous Holocene Pleistocene Pliocene Miocene Oligocene Eocene Paleocene Late Cretaceous Early Cretaceous Thymallus Oncorhynchus Salvelinus Prosopium Hucho Smilodonichthys Rhabdofario Umbridae Salmo Eosalmo Thaumaturus Natlandia Goudkoffia Pseudoberyx Ginsburgia Gharbouria Gaudryella Barcarenichthyes Helgolandichthys Pseudoleptolepis Chardonius Casieroides Quaternary Neogene Paleogene Cretaceous Holocene Pleistocene Pliocene Miocene Oligocene Eocene Paleocene Late Cretaceous Early Cretaceous

Notes[edit]

  1. ^ a b c Froese, Rainer, and Daniel Pauly, eds. (2008). "Salmonidae" in FishBase. December 2008 version.
  2. ^ a b McDowell, Robert M. (1998). Paxton, J.R. & Eschmeyer, W.N., ed. Encyclopedia of Fishes. San Diego: Academic Press. pp. 114–116. ISBN 0-12-547665-5. 
  3. ^ a b c McPhail, J.D.; Strouder, D.J. (1997). "Pacific Salmon and Their Ecosystems: Status and Future Options". The Origin and Speciation of Oncorhynchus. New York, New York: Chapman & Hall. 
  4. ^ Smiley, Charles J. "Late Cenozoic History of the Pacific Northwest". Association for the Advancement of Science: Pacific Division. Retrieved 2006-08-08. [dead link]
  5. ^ Montgomery, David R. (2000). "Coevolution of the Pacific Salmon and Pacific Rim Topography". Department of Geological Sciences, University of Washington. Retrieved 2006-08-08. [dead link]

References[edit]