Fishes, Reptiles, and Amphibians ENVIRON 311/EEB 320 Winter 2007
Feb 03, 2016
Fishes, Reptiles, and Amphibians
ENVIRON 311/EEB 320
Winter 2007
Fishes
Lepisosteus osseus: Longnose gar
Fish Anatomy
Fish Anatomy
• Heterocercal tail– Bony supports extend
through top of caudal fin– Caudal fin asymmetrical
• Homocercal tail– Caudal fin symmetrical– No extension of spine
through top of caudal fin
Family Petromyzontidae• Lampreys• Lack jaws, as well as paired
fins, scales, and gill covers• Body is elongate• Has unique larval stage,
called the ammocoete stage– These lack fully functional
eyes and mouthparts; feed on detritus and drift
• Adults may be parasites, predators or non-feeders– Parasitic kinds use teeth on
sucking disk to rasp feeding holes in fish
Then…
Add some jaws, paired fins, and opercula (gill covers)…
Family Lepisosteidae
• Gars• Long, thin body with heterocercal tail• Ganoid scales are armorlike• Long, fixed jaws and sharp teeth• Can breathe air directly• Usually an ambush predator• Prefers large bodies of water, esp. where weedy areas exist
Family Amiidae
• However, upper jaw (maxilla) is now more mobile• Often confused w/ snakehead, an invasive species
– Bowfin has a shorter anal fin, heterocercal tail, and a gular plate (hard plate on throat)
• A large, powerful ambush predator—occupies mainly weedy spots
• Bowfin or Dogfish
• Another very primitive fish with a hetero-cercal tail and the ability to breathe air
Family Amiidae
Now…
Turn the primitive heterocercal tail into a homocercal tail and…
Family Salmonidae
• Trout, Salmon, and Ciscoes
• Single soft dorsal fin with fleshy adipose fin and small scales
• Medium to large freshwater fishes—very important to sport and commercial anglers
• High O2 demand—needs cold water (e.g. ground-water streams and deep oligotrophic lakes)
• Most are predatory, first on invertebrates and then on other fish
• Some are migratory
Family Umbridae
• Mudminnows• Soft dorsal fin placed far
back on body• Rounded caudal fin• Small, hardy fish with ability
to survive under low DO; found in a wide variety of habitats
• Preys mainly on invertebrates
• Very closely related to pikes, which it resembles
Family Esocidae
• Pikes and pickerels• Soft dorsal fin place far back
on body, roughly even with anal fin
• Caudal fin is slightly forked• Snout is duck-billed in
appearance• Voracious ambush predators
of streams, lakes, and many wetlands – Feed primarily on other fish,
including their own kind
Family Cyprinidae• Minnows• Simple looking with single soft
dorsal fin• Mouth ranges from subterminal
to upturned• Usually without complex
patterning but occasionally colorful
• Very large and diverse family• Includes shiners, carps, and
goldfish (the latter two are invasive exotics)
• Wide variety of feeding strategies—some are filter feeders, others predators
Asian Carp…getting closer• bighead and silver• imported by catfish
farmers to remove algae and suspended matter out of their ponds
• Jump out of water and can injure boaters
• Separated from Lake MI by an electric barrier
www.epa.gov
Family Catostomidae
• Suckers and redhorses
• Look like cyprinids but have ventral mouth (suckerlike) with thick lips
• Redhorses may be colorful and grow quite large
• Benthic—sift through sediments for invertebrates and sometimes algae
Family Ictaluridae
• Catfishes• Barbels, adipose fin and
single spines in both the pectoral and dorsal fin characterize family
• Are without scales• Many are benthic• Size ranges from tiny to
enormous• Extra taste buds on body
allow catfish to locate food where light levels are low
Then…
• Add spines to dorsal and anal fin
• Bring the pelvic fins closer to the pectoral fins
Family Percidae
• Perches, darters, and walleyes
• Two dorsal fins: one spiny and one soft
• Anal fin with 1-2 spines• Opercular spines• Darters are generally small
and are primarily benthic• Others are good swimmers,
voracious predators (first of inverts, then fish) and medium-sized
Family Centrarchidae
• Sunfishes and tropical basses
• Two dorsal fins, usually connected
• Anal fin with 3 or more spines
• Includes many sport fishes
• Small to medium predators of inverts and other fish
Family Cottidae
• Sculpins• Two dorsal fins• Tend to be dorso-ventrally
flattened, with large head and dorsal eyes
• Possess pre-opercular spines
• Prefer cool to cold water—often associated with (and eaten by) trout
• Prey mainly on inverts
Family Gasterosteidae
• Sticklebacks• Easily identified by
spiny “finlets” on first dorsal fin
• Caudal peduncle extremely thin
• No scales• Found mainly in quieter
waters—consume invertebrates
Reptiles and Amphibians
Class Amphibia
• Amphibians• Name implies two life stages:
larval and adult• Many live in or near water for
much of their life cycle• Respiration may be
accomplished through lungs, gills or simple diffusion through the skin, depending on species and life stage
• Skin is generally moist, not covered with scales
• Generally sensitive to human impacts on water quality
Order Caudata
• Salamanders• Two to four legs and a long
tail—no claws• Two-thirds of world’s species
live in Americas• Some species retain larval
characteristics throughout life (e.g. external gills)
• Some species estivate during periods of drought,
Order Anura• Frogs and Toads• Most have a familiar tadpole
larval stage that develops in water– Larval stage may last
anywhere from a few weeks to a couple of years
– Feeds on algae, detritus, inverts
• Adult stage has four legs and is typically terrestrial or semi-aquatic– Feeds mainly on invertebrates– Some may eat other frogs or
snakes
Family BufonidaeBufo americanus
• American toad• Warty skin and short legs for
hopping (characteristic of toads)
• Adult occupies all kinds of terrestrial habitats, returns to water (often ephemeral) to breed
• Tadpole is dark, has rounded tail with little pigment around the edges
Family Hylidae
• Treefrogs • Slender, long limbs
and digits • Usually small• May be somewhat
arboreal
Family HylidaeHyla versicolor/chrysocelis
• Gray treefrog• Has adhesive pads on
long toes, adapted to climbing
• Adults warty with bright coloration under legs
• Usually stay close to swampy areas
• Tadpoles strongly patterned—may also be tinged with color
Family HylidaePseudacris crucifer
• Spring peeper• Very tiny—more likely to
be heard than seen– If seen, can be identified
by ‘x’ on back
• Adults are somewhat arboreal, preferring swampy areas
• Tadpoles tiny, with lightly mottled tails
Family Ranidae
• True frogs• Skin fairly smooth
with well-developed legs for leaping
• Front toes lack adhesive pads and webbing; rear toes are webbed
Family RanidaeRana catesbeiana
• Bullfrog• Adults are large, with no
dorsolateral ridges and usually little patterning on body
• Voice is deep croak• Spend much of life in or
very close to water• Tadpoles are large; may
take two seasons to mature
Family RanidaeRana pipiens
• Leopard frog• Adult has dorsolateral
ridges and dark, round spots on back
• Voice is snore-like• Found in wide variety of
wetlands; sometimes wanders into dry meadows
• Tadpole mottled throughout
Family RanidaeRana sylvatica
• Wood frog• Adult easily identified by
dark mask across face• Voice sounds like clucking • Prefers wooded
bottomlands• Usually breeds early;
sometimes before ice is off of lakes
• Tadpole develops quickly; has high, relatively unmarked dorsal fin
Class Reptilia
• Reptiles• Have scales (few
exceptions) and clawed toes (if they have toes)
• Young resemble adults
Order SquamataSuborder Serpentes
• Family Colubridae: Water snakes
• Nerodia sipedon sipedon, the northern water snake is only member in MI
• Is not venomous, but is persecuted by many because of this perception
• Common in/near rivers, swamps, bogs, etc.
Order Testudines
• Turtles• Characterized by
carapace and four clawed legs
• Underbelly called plastron—may be variously jointed
• Some are exclusively aquatic—others are terrestrial
Family ChelydridaeChelydra serpentina
• Snapping turtle• Large, heavily armored
turtle • Three-keeled carapace• Spends much of time
submerged—rarely basks• In water, eats almost
anything• Out of water, will try to
bite almost anything, even cars
Family EmydidaeGraptemys geographica
• Map turtle• Single keel on carapace• Yellow spot behind eye• “Map” pattern on
dorsum• Prefers large bodies of
water• Good swimmer—will eat
fish—but also likes to bask on logs
Family EmydidaeChrysemys picta marginata
• Midland painted turtle• Carapace shallow keel
(in females)• Marked with reds and
oranges on sides and plastron
• Prefers shallow, weedy spots
• Omnivorous
Family TrionychidaeApolone spinifera spinifera
• Eastern spiny softshell
• Carapace is soft and pliable—has chocolate-chip pattern
• Head is small with long snout for snorkeling
• Mainly a turtle of large rivers– Spends lots of time
swimming– Sometimes basks on logs or
rocks, but always where water is close by
• Largely predatory on fish and inverts
The End