World Families II:
Marine pelagic and tropical
freshwater fishes
November 27, 2012
Marine Pelagic Fishes
• Of >25,000 known fish species, ~15,000 are marine
• Majority are associated with seafloor, but a diverse
community also occupies open water pelagic zone
• More mobile and wide ranging than benthic fishes
• Vary from small, schooling fish to large predators
Family List
Engraulidae: anchovies
Exocoetidae: flying fishes
Megalopidae: tarpons
Scombridae: tunas
Sphyraenidae: barracudas
Sphyrnidae: hammerhead sharks
Istiophoridae: billfishes
Engraulidae: anchovies
• Mouth inferior, very large, upper jaw
produced
• Gill rakers often numerous
• Silver stripe down flanks
• Abdominal scutes in OW species
• Most species <15cm
Exocoetidae: flying fishes
• Name means “outside of home”
• Unusually large pectoral fins, some species also with
large pelvic fins (four-winged appearance)
• Jaws relatively short
• Caudal fin deeply forked, upper lobe shorter
http://www.youtube.com/watch?v=8nEwte-x-iw
Megalopidae: tarpons
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Large silvery fishes of tropical and subtropical waters
Single dorsal fin without spines
Fusiform, compressed body
Lower jaw prominent
Filamentous last dorsal ray
Scombridae: tunas
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Body elongate and fusiform
Snout pointed, premaxilla beaklike
Mouth large with variable teeth
Two dorsal fins, separate
5-12 finlets behind 2nd dorsal and anal
Caudal deeply forked
Sphyraenidae: barracudas
• Elongated body
• Large-mouthed with lower jaw projecting
forward bearing strong fanglike teeth
• Upper jaw non-protractible (large prey)
• Low pectoral fins, dorsal fins
far apart
Sphyrnidae: hammerhead sharks
• “sphyrna” = hammer
• Head laterally expanded, with eyes and nasal
openings wide-set (compared to other sharks)
• Blades presumed to increase sensory capabilities
• No spiracle
• Viviparous
Istiophoridae: billfishes
• Name means “sail carrier”
• Premaxilla and nasal bones extremely
elongated, forming spearlike bill or
rostrum
• Very narrow pelvic fins
• Median keel on caudal peduncle
Tropical Freshwater Fishes
Tropical Freshwater Fishes
• Tropical aquatic habitat includes some of the world’s
largest rivers, e.g., the Amazon, Madeira, Mekong,
Orinoco, Negro, and Zaire
• Tropical freshwater fishes threatened by rainforest
destruction, damming of rivers, pollution, erosion,
pet trade, introduction of exotics
Family List
*Cichlidae: cichlids
Gasteropelecidae: freshwater hatchetfishes
Polypteridae: bichirs
Potamotrygonidae: freshwater stingrays
Toxotidae: archerfishes
Channidae: snakeheads
Loricariidae: sucker-mouthed armored catfishes
Protopteridae: African lungfishes
Ceratodontidae: Australian lungfishes
*Osteoglossidae: arowanas
Arapaimidae: arapaima and relatives
*Lepisosteidae: gars
*will not be tested
*Cichlidae: cichlids
• Body shape variable, mostly
moderately deep and compressed
• Interrupted lateral line in most
• Breeding activities highly organized
• Mouthbrooders, substratebrooders
• Highly speciose and widely
distributed
• Hippo cleaners
*will not be tested
Gasteropelecidae: freshwater
hatchetfishes
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Enlarged, strongly convex muscular pectoral girdle
Single dorsal fin, adipose fin present in larger species
Jumping capabilities thanks to long pectorals
Found in Central and South America
Name means “stomach axe”
Polypteridae: bichirs
• Name refers to series of finlets on dorsum
• Body elongated or anguilliform with thick
rhombic/ganoid scales
• Symmetric caudal fin
• Pectorals with lobed base
• Some species without pelvics
Potamotrygonidae:
freshwater stingrays
• Name means “river,” “three points”
• Med to large batoids, with short stout tail
• Dorsal surface usually covered with
thorns or denticles
• Most with spotted/colorful dorsum
• Outline round
Toxotidae: archerfishes
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Compressed, deep body
Large eyes
Mouth long with lower jaw longer
Anal fin with three spines
Spiny and soft dorsal continuous
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archerfish on BBC
Channidae: snakeheads
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2 genera (1 Asian 1 African)
Elongate body
Lower jaw protruding
Long dorsal and anal
No spines in fins
Introduced in CA, MD, and
Southeast
Loricariidae: armored catfishes
• Body covered with bony plates
• Ventral sucker mouth, some
with barbels
• Adipose fin absent or, when
present, with spine at front
Protopteridae: African lungfishes
• Body moderately elongate
• Threadlike pectorals and pelvics
• Able to survive dry spells by aestivation
(reduced metabolism, burrowed in mud
and enveloped in mucus cocoon)
• lungfish aestivation
Ceratodontidae: Australian lungfishes
• Stout, elongate body with flattened
head and small eyes
• Large bony scales cover body
• Fins flipper like
• Caudal fin paddle shaped
Arapaimidae: bonytongues
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2 species: Arapaima and Heterotis
Heterocercal tail
Torpedo shaped body, large scales
Long anal and dorsal set far back
Pectorals low, pelvics set far back
Air breathers
*Osteoglossidae: arowanas
• Elongate, slender body with large scales
• Barbels present at symphasis of lower jaw
• Large mouth with markedly oblique
gape
• Name means “bony tongue”
*will not be tested
*Lepisosteidae: Gars
• Atractosteus tropicus – tropical gar
• Distribution from Mexico to Costa Rica
• Aquacultured as food fish; also overfished
*will not be tested (on world families section