FISH 311 Exam 1

Dorsal

Direction towards the spine of the Fish

Anterior

Direction towards the front of the fish

Posterior

Direction towards the back of the fish

Ventral

Direction towards the bottom of the fish

Medial

Direction in the middle of the fish

Lateral

Direction on the sides of the fish

Proximal

Direction towards the fish

Distal

Direction further away from the fish

Pointed Caudal Fin

Caudal fin with slow, snake-like movements

Rounded Caudal Fin

Caudal fin with a large amount of surface area that creates drag, but is effective for maneuvering and acceleration

Truncate Caudal Fin

Caudal fin with not as much drag as a rounded shape, but still effective in maneuvering and acceleration

Emarginate Caudal Fin

Caudal fin with not as much drag as rounded or truncate shapes, but is still effective in maneuvering and acceleration

Forked Caudal Fin

Caudal fin with much better acceleration, still good maneuvering, less surface area so less drag

Lunate caudal fin

Caudal fin that is rigid with less surface area so it has great acceleration, but less maneuverability

Heterocercal caudal fin

Caudal fin that is only found in primitive fishes like sharks, sturgeon, and paddlefish

Superior mouth shape

Mouth shape that opens towards the dorsal side

Terminal mouth shape

Mouth shape that opens anteriorly

Subterminal mouth shape

Mouth shape that opens slightly ventrally

Inferior mouth shape

Mouth shape that opens ventrally

Tubular mouth shape

Mouth shaped like a tube

Elongated mouth shape

Mouth shape with a long mouth

Protrusible mouth shape

Mouth shape that can extend forward

Rover-predator body form

Body form with a fusiform body, pointed head, terminal mouth, narrow caudal peduncle, forked or lunate caudal fin, and fins distributed for stability and maneuverability. They capture prey by pursuit.

Lie-in-wait predator body form

Fusiform and elongated body shape, flattened head, large eyes, large mouth with large teeth, posterior dorsal fin, and large amount of thrust for high speed acceleration in short bursts

Surface-oriented body form

Body form with upward pointing mouth, dorso-ventrally flattened, posterior dorsal fin that captures prey near water surface and can take in oxygen from air

Bottom-dweller body form

Diverse body form with an often reduced swim bladder

Deep-bodied body form

Body form that is laterally compressed, has long dorsal and anal fins, high pectoral fins, anterior pelvic fins under pectorals, and able to maneuver in tight quarters

Eel-like body form

Body form that is elongated, has tapering or rounded tails, small paired fins, long unpaired fins, small scales, and is adapted to live in small crevices or burrowing

Ancestral Traits

Characters with a similarity to a common ancestor and has a long history of being well-adapted with little change over time

Derived Traits

Characters which differ from common ancestor forms. They have a substantial evolutionary change.

Ancestral

Ancestral or Derived: paired fins abdominal

Derived

Ancestral or Derived: paired fins thoracic

Ancestral

Ancestral or Derived: fin rays

Derived

Ancestral or Derived: increased spininess

Ancestral

Ancestral or Derived: long fusiform body with many vertebrae

Derived

Ancestral or Derived: short compressed body with fewer vertebrae

Exoskeleton

Dermal bone, ossifies directly, phylogenetically older

Endoskeleton

Phylogenetically younger, either perichondral or endochondral

Perichondral bone

Bone on surface of cartilage

Endochondral bone

Ossifies by replacing carticale

Notochord

Primitive support structure, supports body when swimming, present in all embryos, present in adult sharks, sturgeons, paddlefish, and coelacanths

Precaudal vertebrae

Has a neural spine, neural arch, intermusculars, centrum, and ribs

Ancestral

Ancestral or Derived: more intermusculars

Caudal Vertebrae

Has a neural spine, neural arch, centrum, haemal arch, and haemal spine

Flexion

Process of the notochord bending to create the caudal fin

Urostyle

The bone that is bent at the end of the vertebral column

Epurals

Small elongated bones at the top of the caudal fin

Hypural

Flattened bones that mainly support the caudal fin

Parahypural

Narrow bones at the bottom of the caudal fin

Derived

Ancestral or Derived: hypural fusion

Pterygiophore

Supports fin rays internally and attaches to muscles. Has 3 segments.

Derived

Ancestral or Derived: Fused segments in the pterygiophore

Rays

Segmented, sometimes branched fins, usually soft with paired elements

Spines

Not paired, branched, or segments, usually stiff type of fins

Derived

Ancestral or Derived: Spines

Mandibular arch

Developmental region in jawless fishes that become jaws

Hyoid arch

Developmental region in jawless fishes that supports jaws

Branchial arches

Developmental region in jawless fishes that support gills

Pre-mandibular region

Developmental region in jawless fishes that is anterior to the mouth

Dermochranium

In early jaws, dermal bone layered on top of the cartilage

Chondrocranium

In a shark head, where the brain and sensory organs are

Splanchnocranium

In a shark head, where the jaws and the hyoid are

Amphyistylic

Jaw suspension in basal sharks. The palatoquadrate is attached to the chondrocranium and the hyoid arch supports both jaws.

Hyostylic

Jaw suspension most common in chondrichthyans. There is no otic process and it is more flexible.

Autostylic

Jaw suspension in lungfishes and tetrapods. The hyoid arch is no longer involved.

Holostylic

Jaw suspension in holocephali. the palatoquadrate is completely fused with the chondrocranium.

Ancestral

Ancestral or Derived: maxilla attached to opercular apparatus

Derived

Ancestral or Derived: maxilla is mobile and rotates downwards an dforwards.

Derived

Ancestral or Derived: Longer premaxilla which is the functional jaw

Derived

Ancestral or Derived: Large ascending process

Hyoid coupling

Creates suction

Epiaxial muscular

Pulls head back in hyoid coupling

Hypaxial musculature

Causes the rotation of pectoral girdle. The hyoid apparatus is pulled back and down and the lower jaw is pulled down.

Gill rakers

Attached to the gill arch anteriorly, retains prey

Opercular coupling

No suction

Levator operculi

Lifts the opercular apparatus, which pulls back on lower jaw via a ligament. The lower jaw drops.

Phyrangeal Jaws

Modified gill arches which help crush prey at the back of the mouth

Reynolds Number

Re=UL/v, speed U, length L, kinematic viscosity v

High

Reynolds number associated with large and fast fish, where inertia is important

Small

Reynolds number associated with small and slow fish, where viscosity is more important

Scales

Creates microturbulence along skin, maintains laminar flow, and reduces boundary layer separation

Narrow caudal peduncle

Reduced boundary layer separation and turbulent wake

Anguilliform

Low Re, for slow and small fishes. Undulating waves throughout the body. The net force is forward and there is lift. Somewhat inefficient because of the drag. Allows movement backwards

Carangiform/Thunniform

Higher Re. Smaller part of the body is undulating and the fins are stiff with a narrow caudal peduncle.

Yaw, roll, pitch

Movements not in the direction of swimming

Unpaired fins

Fins used as a stabilizer for roll and yaw. Middle of fish aids in turning and posterior allows it to be stable with additional thrust.

Balistiform

Triggerfish. Uses unpaired fins as a main form of propulsion.

Gymnotiform

Swims with the anal fin, highly maneuverable, and can move backwards.

Paired fins

Fins that control pitch, direction, and breaking

Ancestral

Ancestral or Derived: Paired fins inserted horizontally, pelvic fins behind pectoral fins, controls pitch

Derived

Ancestral or Derived: pelvic fins below the pectoral fin, efficient double brakes, allows accurate maneuvering, important pectoral fins

Buoyancy

The ability to float in water. The upward force that a fluid exerts on an object less than than itself.

Squalene

Low-density compounds that are in shark liver lipids and oil, helps control buoyancy

Generating lift

Fish swim forward with water moving faster dorsally compared to ventrally because of its body shape.

Reduce heavy tissues

Deep oceanic fishes control buoyancy this way

Lungs

For respiration, paired, and located ventrally off of the gut

Swim bladder

For buoyancy control, single, and located dorsally off of the gut

Physostomous

Swim bladder with a connection to the esophagus. Air can be taken up and released through the mouth.

Physoclistous

Swim bladder where gas is added and released using special glands.

Derived

Ancestral or Derived: Physoclistous