Fishes, Reptiles, and Amphibians ENVIRON 311/EEB 320 Winter 2007

Fishes Lepisosteus osseus: Longnose gar

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 O 2 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

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 Bufonidae Bufo 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 Hylidae Hyla 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 Hylidae Pseudacris 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 Ranidae Rana 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 Ranidae Rana 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 Ranidae Rana 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 Squamata Suborder 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 Chelydridae Chelydra 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 Emydidae Graptemys 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 Emydidae Chrysemys 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 Trionychidae Apolone 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