Herp Last Test Notes PDF

T17 - feeding - Why are there different feeding modes - Most herps are carnivorous - Eat a wide variety of prey - Also a wide variety of ways of eating it - Feeding modes depend on - Environment - W...

T17 - feeding - Why are there different feeding modes - Most herps are carnivorous - Eat a wide variety of prey - Also a wide variety of ways of eating it - Feeding modes depend on - Environment - Water or air - Prey characteristics - Morphology of predator - Phylogenetic constraints - There is a huge difference between feeding in air vs. water - Drage is much higher in water - Ventilation of lungs and gills can create difference problems - Water - Primarily suction feeding - Air - Large diversity of feeding modes - Agkistrodon piscivorus eats fish in water and rodents in air - How does the strike behavior differ in air and water? - Water - Will open and close mouth so fish doesn't swim away - Air - Wil open and then close and then open bc if it gets away it can chase and wait - What aspects are similar/same? - They open their mouths more than they need to contact the animal - Filter feeding - Common in tadpoles - Buccal floor is raised and lowered using muscles - Food is filtered from the water projections of the gill slits and secreted mucus - Suction feeding - Extreme expansion of the buccal cavity - Mouth opens - Water and prey floods in - Buccal expansion associated with the hyoid apparatus - Tadpole mouth part position - Similar situation seen in many fishes - Tadpoles feed - On stream bottoms - Mouth is facing down - In bromeliads - Mouth is like 45 degree angle down to the ground - Skim the water surface  - Mouth is facing up to the surface - Feed off rocks in ponds - Mouth is normal - This is so they can swim normally without having to move their neck - Bc of vertebrates - How do herps feed in air - What are key difference between the skulls of a turtle ( anapsid ) and a viper ( modified diapsid ) - Turtle - Beak - Crushing - Akinetic - Viper - No beak - Piercing - Very kinetic skulls - Akinetic feeding - Akinetic, non-projectile feeding - Turtles have a very solid skull - Not much space for muscles - Emargination provides space for muscles by creating a trochlear notch - Muscles fill the notch, but are positions posteriorly - Force of adductor mandibulae is directed parallel to body axis - Trochlear process redirects muscle fibers - Evolved twice independently - Where the muscles bends from L-R to U-D - Projectile feeding - Independently evolved - Urodela ( most ) - Anrura ( some ) - Chamaeleonidae ( all ) - Origin from a moist, sticky tongue - Subsequent elongation - Bufonidae : Rhaebo guttatus - Genioglossus muscle flips sticky pad - Over the contracting submentalis muscle - Hyoglossus retracts pad ( refold tongue ) - Plethodontidae - Lugless decoupled breathing and feeding - Allowed diversification - Tongue projection in plethodontids - Ballistic mechanism - Stretching tendons and use elastic recoil - Faster and less temperature sensitive than muscular power  - Similar to using a rubber band to flick tongue - Chamaeleonidae - Can project tongue twice its SVL - Associated with binocular vision for gauging distance - Depth perception - Tongue moves fat, so the chameleon doesn't have to - Projectile feeding in chameleons - Also involves hyoid apparatus and a number of specialized muscles - Accelerator muscle is wrapped around the colossal process - As accelerator muscle contracts, it squeezes off the EP and shoots out - Velocity = 5.8 m/s - Acceleration = 486 m/s - Hyoglossus retracts the tongue after projection - Kinetic feeding - Seen in squamata - Extra joins in the skull - Allow more mobility - Allow more complexity - “Lizards” have up to 3 joints in addition to the mandibular one - Streptostylic joint - Quadrate-squamosal joint - Loss of lower temporal bar allows more quadrate motion - Leads to increased gape - Mesokinetic joint - Frontal-parietal joint - Increased gape via elevation of snout - Faster mouth clothing, including bite force - Metakinetic joint - Parietal-supraoccipital joint - Similar to mesoskinetic - Least movement out of these - Reduction in cranial kinesis - Chamaeleonidae - Projectile feeding instead - Lost meso and metakinetic joints - Dracaena ( Teiidae ) - Durophagous - Same reduction as in Chamaeleonidae - Also specialized teeth for crushing snail shells - Other teiidae are insectivores - Various herbivores - Static feeding - Most lizards - Grasp prey and manipulate using tongue or environment  - Inertial feeding - Varanidae use the prey’s weight for ingestion - Mouth moved relative to prey using jerking motions - Kinetic feeding in snakes - Large problem - Small head relative to body weight - Need to take in a lot of food - Solution : highly kinetic skull - Allows eating of large prey - Have extra skull and mandibular joints - Increased connective tissue - Decreased bone fusion - Ability to move each side of the jaw independently - Palatal teeth hold prey while maxillary jaws walk it up - Can walk maxilla to grab/move more or less of the animal - A braincase has formed to protect brain from forces from prey - Down-growth of frontals and pariertals - Loss of meso and metakinetic joints - New joints evolved - Prokinetic joints - Between frontals and nasals - Hyper extend the nose - Intra-mandibular - Drops toothrow - Hyperextension - Loss of mandibular symphysis - Allows later spreading of the lower jaw - No fusion of left and right side of jaw - Bottom row - Akinetic feeding in snakes - Scolecophidia - Need rigid skull for burrowing - Streptostylic - Other cranial joints lost - Use lower teeth for “mandibular raking” to overcome prey - Eats small prey, but lost of them - Termite pupae - Prey capture - Egg-eating snake ( Dasypeltis ) - Use modified hypapophysis to rush shell and cut membranes - Regurgitate shell - Aglyphous snakes hold prey with teeth and constrict - Morelia viridis and Corallus caninus have long teeth to penetrate bird plumage - Fish eaters just jod prey with teeth  - Most venomous snakes do not constrict - Envenomation - Often let go of prey after strike to avoid injury - Envenomation - High cranial kinesis has facilitated the evolution of longer fangs - Opisthoglyphs have relatively short fangs - Anterior shift in proteroglyphs and solenoglyphs provides space for longer fangs - Also rotating maxilla in solenoglyphs - Venomous snakes - Opisthoglyphs - Solenoglyphs - Proteroglyphs - Muscles compressing the venom gland are not homologous - Proteroglyphs - M. adductor superficialis - Solenoglyphs - M. compressor glandulae - Also different venom composition - Proteroglyphs - Primarily neurotoxic - Like a cobra - Solenoglyphs - Primarily haemotoxic - Like a viper - Evolution of venom - Happened twice - Convergent evolution - Origin of venom - Outside of serpentes, only the helodermatidae were considered venomous - Some elements of derived venom are found elsewhere ( toxicofera ) - Anguidae - Varanidae - Iguania - New molecular phylogenies suggest all these groups form a clade - Helodermatidae - Venom is just for defense - In the lower jaw - 9 venom proteins are shared by the venom clade - Anguimorphs have 1 unique protein, helodermatidae have 2 more - Serpentes have 16 derived proteins that have been sequenced T18 - Diets and foraging - what factors influence diet and foraging mode - Diet refers to what an organism eats - Foraging mode refers to how prey are obtained - Many factors influence diet and foraging mode - Size - Habitat - Geography - Level of cranial kinesis - Digestive proteins - Resource availability - Activity time - Completion - Age - Behavior - History - What do herps eat - Amphibians and “reptiles” are - Carnivores - Most herps ~90% - Mostly insectivores - Omnivores - Often viewed as generalists - Opportunism - Herbivores - Relatively few species - A number of important adaptations - Adaptations for diet - Gape size and body shape - To eat a prey item, it has to fit - Big mouths, wide heads for large prey - Small mouths, narrow heads for small prey - Gape limitation - Predators are limited at eating because of gape size - Can die because prey was too big - Species that eat large prey either have - Relatively broad mouths - High cranial kinesis - Crocodilians - Robust teeth - Secondary palate - Death roll behavior - Snake is gape limited because jaw doesn't open that much - Herbivory has evolved in  - Many anuran tadpoles - Some testudines - Some lizards - Longer guts and caecal valves - Caecal valves are will developed in many Iguanines - Slow down food to digest - Caecal valves have evolved de novo in a population of Podarcis sicula in