Fishes, Reptiles, and Amphibians

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

2. Fishes Lepisosteus osseus: Longnose gar

3. Fish Anatomy

4. 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

5. 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

6. Then… Add some jaws, paired fins, and opercula (gill covers)…

7. 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

8. Family Amiidae • Bowfin or Dogfish • Another very primitive fish with a hetero-cercal tail and the ability to breathe air • 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

9. Family Amiidae

10. Now… Turn the primitive heterocercal tail into a homocercal tail and…

11. 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

12. 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

13. 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

14. 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

15. 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

16. 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

17. 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

18. Then… • Add spines to dorsal and anal fin • Bring the pelvic fins closer to the pectoral fins

19. 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

20. 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

21. 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

22. 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

23. Reptiles and Amphibians

24. 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

25. 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,

26. 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

27. 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

28. Family Hylidae • Treefrogs • Slender, long limbs and digits • Usually small • May be somewhat arboreal

29. 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

30. 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

31. Family Ranidae • True frogs • Skin fairly smooth with well-developed legs for leaping • Front toes lack adhesive pads and webbing; rear toes are webbed

32. 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

33. 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

34. 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

35. Class Reptilia • Reptiles • Have scales (few exceptions) and clawed toes (if they have toes) • Young resemble adults

36. 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.

37. Order Testudines • Turtles • Characterized by carapace and four clawed legs • Underbelly called plastron—may be variously jointed • Some are exclusively aquatic—others are terrestrial

38. 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

39. 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

40. 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

41. 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

42. The End