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Herpetology 1


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defining char of amphibians
permeable skin allows for gas and water exchange
salamanderselongte trunk +tail most reurn to water purely aq = paedomorphasis
frogs short hind limbs = walk/ hop long = jump/ swim caudal vertbrae fused, legbones fused males develop nuptuil pads conc of glands (parotoid) for defense (exudes toxin) reduced skull, teeth absent from mandible tadpole mouthpart structure used for ID
Caecilians tropical, legless, burrowing or aq, rel unknown chemosensory organ called tentacle well ossified skull annuli assoc. with vertebrae body w/ sub-q scales
unifying char of reptiles
there isn't one
non-avian reptile groups
all (exc crocs) have a 3-chambered heart Testudines (turtles) Squamata (lizards and snakes) crocodilians Rhychocephalia (tuatara)
what is unifyling char of reptiles and amphibians?
ectothermy (= and -)
aqcuisition of heat from sun, hot rocks + -> 1/10 energy needed, 50% of food converted o new tissue - -> env dictates body temp, potential limits o life performance efficiency of energy conversion directly affects endothermic pops
Amphibian and reptile future
disease/ pathogens habitat destruction, highways UV radiation pesticides exploitation
Willi Hennig model
phylogenetic systems (cladistics) emphasizes the impt of monophyletic lineages
phylogenetic systematics
use of derived chars
derived char
shared derived char (ex) nasolabial groove of plethodontic salamanders
ancestral char (ex) ectothermy
hypothesis of evolutionary relationships
common ancestor plus some of descentends (ex) reptilia (excludes birds)
tailed frogs (ext of cloaca) do not call, no tympanic membrane, no vocal sacs internal fertilization found in fast water
sister group
adjacent branhes of a cladogram usu refers to terminal branching, most closely related
demonstrate relationship of a clade (ex) putting fish in a clade for reptiles
What are the needs of an org to move from water to land? (8)
lungs legs/ skeletal structure (weight bearing w/ movement) -fore = humerus, radius, ulna -hind = femur, tibia, fibula movement of eyes dorsally jaws to obtain food (teeth and/or tongue) modified sensory system (inc ear) kidneys- nitrogenous waste removal
Lissamphibia synapomorphies (10)
1. Pedicellate (sits on jaw) and bicuspid teeth (inner and outer edge) 2. Middle ear w/ stapes and operculum (uniq structure that attaches via muscle to pectoral girdle) 3. fat bodies derived from germinal ridge (dev of gonads) 4. mucus and poison glands in skin 5. green rods in retina (not in caecilians) 6. sheet of muscle that elevates eyes 7. cutaneus resp system and buccopharyngeal pump (forces air into mouth and lungs) 8. short, straight ribs that do not encircle body 9. 2 occipital condyles for skull movement 10. reduced skull bones (either missing or hightly modified) -> light skull helps them get around
Paedomorphic traits of Lissamphibia
1. Bones of skull only include early developed bones of ancestor 2. Eyes are large 3. retention of bicuspid teeth
unique derived chars
eel-like in appearance lack pelvic girdles lack marginal teeth reduced digits of forelimbs fully aq eat crayfish, crustaceans have external gills -> indicates poorly oxygenated water will aestivate under stressful ecological conditions (burying in summer, can cover in mucus cocoon) inc Sirens
adults retain one pair of gill slits (paedomorphic) have flattened heads and lidless eyes largest salamanders males defend and guard nests inc Hellbenders
similar to Sirens in appearance have 4 tiny limbs and teeth prefer slow moving waters female tends to terr eggs
most diverse group of salamanders lungless -> attributed to fast waters w/ plenty of oxygen nasolabial groove assists w/ chemoreception lots of variation some adults purely aq, others fossorial, arboreal, scansorial may have egg brooding habitat diversity and specialization
males have squared glands posterior to vent reduced lungs larval periods up to 5 years (dom factor is environment)
some are newts (rough dry skin) suction feeding (in water) and tongue protrusion (in terrestrials) have an eft stage where immature becomes terr then returns to water where it matures (may last up to 14 years) elaborate courtship some have highly toxic skin glands
large w/ many ancestral char hybrids are often polyploids that reproduce by gynogenesis
(amphibian) larva hatch with all 4 limbs prefer fast, cold water may retian gills -> perm aq
metatarsal tubercle (spade) of hindhoot used for burrowing vertical pupils can find in deserts breed in ephemeral ponds, rapid development
teeth entirely absent parotoid glands most terr would call most toads females deposit massive strings of eggs ~1/10 of all frog spp
treefrogs most arboreal w/ enlarged toes discs most are strong jumpers some secrete substance to coat body, prevents desiccation paraphyletic group, don't know how to break up
rel small fossorial, terr, arboreal "narrow mouthed frogs" variety of life histories
paraphyletic- no know shared derived character extremely varied
aka Chelonia shell inc ribs, vert, part of pectoral girdle shell comp of dorsal carapace and ventral plastron hinge in plastron anapsid TSD
snapping turtles large headed w/ powerful jaws can't retract head, neck, limbs shell is rel small stands on hindlegs for defense macroclemys- alligator snapping turtle, has fleshy projection on tongue to attract fish
Cheloniidae + Dermochelyidae
sea turtles forelimbs more dev than hindlimbs eggs laid on tropical beaches migrate using magnetic fields
most are freshwater or semi-aq only one prefers brackish water (Diamond Terrapin) omnivore
land turtles or tortoises domed shell effective against predators stout limbs to carry a heavy body- reduced digits
soft shelled turtles flattened bodies and shell w/ reduced bones covered w/ leathery skin ling necks fully aq mostly carnivorous elongate snout and fleshy lips non-keratinous beak
mud and musk turtles small and stinky (cloaca gland) all are carnivorous

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