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Explore the diverse body forms and propulsion mechanisms of sharks, skates, and rays. Learn about the different types of tails, fins, and locomotion techniques used by these fascinating creatures. This fascinating documentary film provides an in-depth look at the unique locomotion strategies of these aquatic animals. Dive into the world of sharks, skates, and rays and discover their secrets of movement.
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Natural History of Sharks, Skates, and Rays Locomotion MARE 394 Dr. Turner Summer 2008
Body Form & Propulsion Body form: Distinctive heterocercal tail External morphological symmetry Ventrolateral winglike pectoral fins extending laterally from the body Distinct from actinopterygian (bony) fishes
Body Form & Propulsion Teleost body forms and propulsion mechanisms Anguilliform Carangiform Subcarangiform Ostraciform
Propulsion Mechanisms A&B – Rover Predator C – Lie-in-wait Predator D – Surface Oriented Fish E – Bottom Oriented Fish F – Bottom Clinger G – Flatfish H – Rattail I – Deep-bodied Fish J – Eel-like Fish
Body Form & Propulsion Chondrichthyan body forms and propulsion mechanisms
Body Forms and Fin Shapes Great degree of variability in paired & unpaired fins of sharks – 4 body forms Body Type 1: conical head, large deep body, large pectoral fins, narrow caudal peduncle with lateral keels
Body Form 1 Conical head Large deep body Large pectoral fins Narrow caudal peduncle with lateral keels High aspect ratio tail (high heterocercal); externally symmetrical Thunniform propulsion Fast swimming sharks; reduced pelvic, 2nd dorsal, and anal fins
Body Form 1 External symmetrical tail aligns mouth with center of mass & thrust to increase feeding efficiency
Body Form 2 Flattened ventral head Less deep body Large pectoral fins Lower heterocercal Lacks keels Subcarangiform propulsion
Body Form 2 Greatest range of swimming speeds Moderately sized pelvic, 2nd dorsal, and anal fins – highly maneuverable
Body Form 3 Large head Blunt snout Anterior pelvic fins More posterior 1st dorsal fin Low heterocercal; small to absent hypochordal lobe, large subterminal ,lobe Subcarangiform propulsion
Body Form 3 Slow swimming speeds; epibenthic, benthic, & demersal
Body Form 4 Wide variety of body shapes United by few characterisitics Lack anal fin Large epichordal lobe Anguilliform propulsion Typically deep to deep-sea
Body Form 4 Typically deep to deep-sea
Body Form 5 Body dorso-ventrally flattened Enlarged pectoral fins Reduction in caudal ½ of body Typically benthic; some pelagic Most batoids, angelsharks, mylobatiforms & Rajiforms
Body Form 5 Most batoids, angelsharks, mylobatiforms & Rajiforms Undulatory Oscillatory
Body Form 6 Laterally compressed Undulate pectoral fins; not axial body Tail long and tapering (leptocercal) to heterocercal
Locomotion in Sharks Orientation of the body one of most important factors 1° means of force Induced swimming with body horizontal (x) and no vertical (y) motion produces positive body angles (lift) Angle of attack decreases as speed increases toward 2l/s
How Locomotion is Measured High speed imagery recorded of shark along with reflective particles in wake
Locomotion in Sharks Motion of the tail is a key aspect to locomotion – complex 3d manner Kinematics indicates the shark caudal provides thrust and lift by moving water posteriorly and ventrally
Locomotion in Sharks 2 distinct types of pectoral fins in sharks Aplesodic – cardilagenous radials are blunt and extend up to 50% into the fin with the distal web supported only by ceratotrichia* Plesodic – have radials that extend more than 50% into the fin to stiffen it and supplement the support of the ceratotrichia *unsegmented, filamentous fin rays
Locomotion in Sharks Aplesodic fins are more maneuverable; may be used for “walking” on substrate
Locomotion in Sharks Heterocercal tail angle causes a change in body angle
Locomotion in Sharks Which causes lift in a swimming shark Degree of lift is dependent upon the type of tail
Locomotion in Sharks Body orientation, tail thrust, and maneuvering the pectoral fins all coordinate in force balance during swimming
Locomotion in Skates & Rays Batoids either undulate or oscillate the pectoral fins
Locomotion in Skates & Rays Basal batoids (guitarfishes, sawfishes, & electric rays)– undulate thick tails like sharks
Locomotion in Skates & Rays Rays use strict pectoral fin locomotion Undulation – stingrays Oscillation – cownose & manta Movie Movie
Locomotion in Holocephalans Chimeras have long flexible pectoral fins; both undulatory & oscillatory