ENWC424 Lecture Notes - Lecture 19: Aquatic Feeding Mechanisms, Pipidae, Giant Salamander
2 May 2018
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ENWC424 Lecture 19 Feeding
• Ectotherms
o Can go extended periods of time without feeding (in aestivation)
o Teeth primitive
o Modification of skull and tongue linked with feeding habits and diets
• Eat prey that fits in mouth
o Swallow whole
• Little mechanical processing
o Spit food in and out of mouths
▪ Palatal crushing/puncture crushing softens prey
• Frogs
o Use elevator bulbi muscles to push food down throat (muscles contract and use bottom
of their eye to push the food down)
• Larger prey items
o Rip chunks
▪ Twisting or shearing
▪ Rotational feeding (spinning until a part is torn off)
• Some caecilians and salamanders and crocodilians
• Aquatic Feeding Mechanisms
o Suction and Suspension Feeding
▪ Food suspended (in water)
▪ Easily manipulated
▪ Swallowing does not require saliva
▪ Pressure waves can move food away from mouth ( as you approach the food
item it can move away in water)
o Suction Feeding
▪ Sucked into mouth with surrounding water
▪ Negative pressure created in buccal cavity by expanding volume
▪ Must be strong and rapid
▪ Aquatic salamanders, frogs, and some turtles
▪ Expelling the water taken in with food
• Unidirectional
o Water flows in mouth and out gill slits
o Gilled salamanders, tadpoles
• Bi-directional
o Water flows in and out of mouth (as the jaws close)
o Non-gilled salamanders, frogs, and all reptiles
• Salamanders
o Suction Feeding Process
▪ Jaws open
▪ Buccopharyngeal cavity expands
▪ (gill slits close)
▪ Water flows into mouth
find more resources at oneclass.com
find more resources at oneclass.com
▪ Mouth is closed
▪ Floor of mouth rises
▪ Water forced out (through gill slits or mouth)
o Labial Lobes
▪ Flesh modifications of lips
▪ Prevents prey escaping from sides of mouth
o • Cryptorahidae ‒ asyetrial sutio feedig (open on side of their mouth to suck
prey in)
• Frogs
o Suction Feeding (e.g., Pipidae)
▪ Lower floor of mouth before opening mouth
▪ Creates negative pressure in mouth
▪ Also uses front limbs to push prey into mouth
• Tadpoles
o Most use suction feeding
o Scrape algae or phytoplankton
o Draw in water continuously
o Water passes across filters that trap suspended particles
▪ Fine strainer or mucus traps
▪ As food accumulates, strands of mucus and food break loose and flow back to
esophagus
o Suction pump
▪ Floor of mouth drops, water flows in
▪ Mouth and nostrils close
▪ Floor of mouth rises
▪ Water forced into pharyngeal cavity
▪ Water passes through food filters and mucus
• Water is forced through spiracle(s)
• Same system used for respiration but more forceful
o Oral disk
▪ Laial teeth detiles ‒ srape algae ‒ attah to sustrate
▪ Ja sheath ‒ gape 8 degrees ‒ srape siultaeously
▪ Mouth-form variable and related to diet
o Spiricle-most frogs on left side
• Turtles
o Suction Feeding
▪ Some aquatic species
▪ Thrust head forward while mouth opens and floor of mouth drops
▪ Compensatory suction
• Food remains stationary ( by opening their mouth and expanding their
bucall cavity they equalized the effect of moving their head forward at
the say time) In other words the prey stays staionary
▪ Inertial suction
• Food drawn into mouth
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Enwc424 lecture 19 feeding: ectotherms, can go extended periods of time without feeding (in aestivation, teeth primitive, modification of skull and tongue linked with feeding habits and diets, eat prey that fits in mouth, swallow whole. Little mechanical processing: spit food in and out of mouths, palatal crushing/puncture crushing softens prey, frogs, use elevator bulbi muscles to push food down throat (muscles contract and use bottom of their eye to push the food down) La(cid:271)ial teeth (cid:894)de(cid:374)ti(cid:272)les(cid:895) s(cid:272)rape algae atta(cid:272)h to su(cid:271)strate. Inertial suction: food drawn into mouth, forcefully bite prey after capture, alternately suck in and eject food item while biting, trio(cid:374)y(cid:272)hidae fleshy lips to pre(cid:448)e(cid:374)t prey es(cid:272)ape, terrestrial feeding mechanisms, tongue projection. Large jaws, powerful muscles: fleshy tongue pads, no teeth, rhamphothecae (cid:894)kerati(cid:374)ized ja(cid:449) sheaths(cid:895) sharp a(cid:374)d serrated (cid:271)road (cid:272)rushi(cid:374)g surfaces in mollusk and crustacean feeders, tortoises use slicing motion, crocodilians.
