Class Actinopterygii Subclass Neopterygii Division Teleostei Subdivision Osteo-glossomorpha Order Hiodontiformes: 1 family, 2 species, mooneyes Order Osteoglossiformes: 6 families, 218 s
Trang 1The Bowfin
The Bowfin, Amia calva, is the only living member of its
genus, family, and order The Bowfin has the abbreviate
heterocercal tail and spiral valve intestine of the gars but also
has teleost-like biconcave vertebrae as well as cycloid scales,
a relatively light scale type also possessed by many teleosts
The Bowfin’s head is exceptionally bony and the throat is
covered by a distinctive large bone, the gular plate Bowfin
swim slowly forwards or backwards by passing undulations
back and forth along their long dorsal fin Bowfin occur
throughout much of eastern North America in backwater,
often swampy areas; they also have a highly vascularized gas
bladder which functions as a lung They are relatively large
and robust (to 1 m and 9 kg) and predatory on anything that
moves Bowfin males guard the young vigorously until they
are relatively large (10 cm)
Teleosts
The division Teleostei (‘‘perfect bone’’) contains most living
fishes Teleosts are not only taxonomically diverse but also
ecologically diverse, occupying every aquatic habitat type and
niche imaginable The 27,000 living teleostean species are
placed in 4278 genera, 448 families, and 40 orders This
in-credible diversity is generally organized into four taxonomic
subdivisions that reflect patterns of evolution that date back to
the Mesozoic These four main subdivisions are the
osteo-glossomorphs (bonytongues), elopomorphs (eels and
tar-pon), otocephalans (herrings and minnow relatives), and the
euteleosts, with the latter group containing the vast majority of
modern bony fishes
Class Actinopterygii
Subclass Neopterygii Division Teleostei Subdivision
Osteo-glossomorpha Order Hiodontiformes: 1 family, 2 species,
mooneyes Order Osteoglossiformes: 6 families, 218 species,
including bonytongues, African knifefishes, and elephantfishes
Osteoglossomorphs derive their name ‘‘bonytongue’’ from
the teeth on their tongue that forms part of their bite These
freshwater fishes occur on all major continents except Europe
The hiodontiforms comprise two species, the Mooneye and
Goldeye, both of which occur in major river systems of
northern North America The osteoglossiforms are much more
diverse The Asian Arowana or Golden Dragonfish, Scleropages
formosus, has been depleted in the wild due to overcollecting
and is now protected under Appendix I of the Convention on
International Trade in Endangered Species (Figure 10) The
Arapaima of South America is one of the world’s largest
freshwater fishes, reaching a length of 2.5 m The African
mormyrid elephantfishes produce and detect weak electric
fields, have large cerebellums, and have a brain size: body
weight ratio comparable to that of humans
Subdivision Elopomorpha
Order Elopiformes: 2 families, 8 species, ladyfishes and
tar-pons Order Albuliformes: 3 families, 30 species, including
bonefishes and spiny eels Order Anguilliformes: 15 families,
738 species, including freshwater, moray, cutthroat, and
con-ger eels Order Saccopharyngiformes: 4 families, 28 species,
including swallower and gulper eels
Elopomorphs all have ribbon-shaped leptocephalus (‘‘pointed head’’) larvae The Atlantic Tarpon is a highly prized gamefish that reaches a length of 2.5 m and a mass of 150 kg Albuliform bonefishes are also popular gamefishes that oc-cupy sandy flats in shallow tropical waters, The 15 families of anguilliform ‘‘true’’ or freshwater eels are distinguished from the approximately 45 other families of ‘‘eel-like’’ fishes that have independently evolved an elongate body Anguillid eels are catadromous, spawning at sea but spending most of their lives in fresh water Muraenid moray eels and their relatives are marine, tropical and warm-temperate, predatory species Synaphobranchid cutthroat eels include an endoparasitic species, the Snubnose Parasitic Eel, which has been found in the heart of a mako shark The saccopharyngiform deepsea gulper and swallower eels have giant mouths but lack many head bones, scales, and fins found in most other fishes
Subdivision Otocephala
Superorder Clupeomorpha Order Clupeiformes: 5 families,
364 species, including anchovies and herrings
Clupeomorphs are small, schooling, silvery, pelagic marine and occasionally freshwater feeders on zooplankton and phytoplankton Herrings, round herrings, shads, alewives, sprats, sardines, pilchards, and menhadens are extremely im-portant commercial species Anchovies range in size from a
2-cm Brazilian species to a piscivorous, riverine, 37-2-cm New Guinea anchovy The largest clupeids are the Indo–Pacific chirocentrid wolf herrings, which reach a length of 1 m and have fang-like jaw teeth Anadromous shads, Alewife, and herrings occasionally establish landlocked populations in rivers, lakes, and reservoirs
Superorder Ostariophysi Order Gonorhynchiformes: 4 families, 37 species, including milkfish Order Cypriniformes:
6 families, 3268 species, including minnows, barbs, algae eaters, suckers, and loaches Order Characiformes: 18 famil-ies, 1674 specfamil-ies, including freshwater hatchetfishes, tetras, and characins Order Siluriformes: 36 families, 2867 species, including North American freshwater, airbreathing, electric,
Figure 10 The Asian Arowana or Golden Dragonfish (Scleropages formosus, Osteoglossidae), an internationally protected species.
Desirable color varieties have sold for as much as $5000 Photo by Marcel Burkhard, Wikimedia Commons, http://en.wikipedia.org/wiki/ Image:Arowanacele4.jpgfile
Fishes, Biodiversity of 463