Anatomical Features: Fins Flashcards
What is the function of the caudal fin?
- propulsion
What is the function of paired-medial fins?
- control/direction of movement
- pitch/roll/yaw
What is the function of fin rays?
- structural support
What fin rays are found in sharks? what are their features?
- ceratotrichia
- stiff, unbranched
What fin rays are found in bony fish? what are their features?
- lepidotrichia
- flexible, segmented, branched
What are the major features of pectoral fins in rover predators and bottom rovers?
- ventral/below midline
What is the major function of pectoral fins in rover predators and bottom rovers?
- stability/steering
What are the major features of pectoral fins in deep bodied and fast swimming predator rovers
- long and pointy
What are the major features of pectoral fins in slower swimming predator rovers?
- more rounded
What are the major features of pectoral fins in deep-bodied fish?
- high on sides
What are the major functions of pectoral fins in deep bodied fish?
- maneuverability, picking-up food
What fish have exaggerated/large pectoral fins?
- flying/gliding fish
- lionfish for display
What do sharks use their rigid pectoral fins for?
- stabilization and diving
What is the ancestral condition of pelvic fins? what is the function?
- ventral/posterior
- assist in steering and breaking
What fish have ancestral pelvic fins?
- rover predators
- bottom rovers (sharks, sturgeon)
What adaptations have occurred in pelvic fins of deep bodied fish? what is the major advantage of this?
- more anterior/below pectoral fins
- maneuverability
What adaptations have occurred in pelvic fins of bottom clingers? what is the major advantage of this?
- large, anterior holding structures
- suction
What adaptations have occurred in pelvic fins of eel-like fish? what is the major advantage of this?
- absent/reduced
- burrow/dig
What is the main feature of dorsal/anal fins in rover predators and bottom rovers? what is the function?
- long
- stability, steering
Where is the dorsal fin?
top of body
Where is the anal fin?
- ventral
What are finlets? what are they found in?
- rearmost fins that reduce drag
- tuna
- dorsal/pectoral fins fold into slots
What are the features of dorsal and anal fins in eel-like fish?
- long and may fuse with caudal fin
What are caudal fins for?
- propulsion (85%)
What does the shape of caudal fins provide info on?
- how fish swims/lifestyle
How do you calculate aspect ratio?
- (AR) = H2/SA
What are the main features of a homocercal tail?
- upper/lower lobes equal size
- most bony fish
- vertebral column = modified base
What are the 2 subtypes of homocercal tails?
- Lunate
- isocercal
What are the main features of lunate tails?
- moon shape
- stiff keel-like caudal peduncle
- deep fork (high aspect ratio)
What is the function of a lunate tail?
- efficient trust generation
- minimal drag
Why is aspect ratio of lunate tail high?
- SA reduced
What fish have a lunar tail?
- fast swimmers (ex. tuna)
What is the main feature and function of isocercal tails?
- lack well-defined lobes
- burst swimming (bad for drag)
What are the main features of heterocercal tails?
- unequal = upper lobes longer than lower
- vertebral column extends into upper lobe
What is the advantage of the vertebral column extending to upper lobe in sharks and sturgeon?
- stiff in sharks which generates lift as they are negatively buoyant
- flexible in sturgeon which does not produce life (like being @ bottom)
What is the main feature of diphycercal tails?
- dorsal and ventral fins merge to form one long caudal fin
- ex. lungfish
What are the main features of adipose fin?
- fleshy
- lacks fin rays
- not for fat storage
What is a major advantage of adipose fin?
- precaudal flow sensor (maneuverability in turbulent waters)
Does adipose fin have functional significance? What did Hatry programs remove it for?
- no
- to ID wild vs not
What are the 2 main hypotheses on significance of adipose fin?
- swimming in post-larval stage
- increases swimming efficiency
What does removing adipose fin cause?
- decrease in maneuverability
What fish is adipose fin a characteristic?
- salmonidae
- smelts
- catfish