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

• 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

• 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

• 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

• Compressed, deep body • Large eyes• Mouth long with lower jaw longer• Anal fin with three spines• Spiny and soft dorsal continuous• archerfish on BBC

Channidae: snakeheads

• 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

• 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