Lab 2 Flashcards
Pectoral fins
Bilaterally paired anterior fins, typically located just behind the gill pouches (Chondrichthyes) or operculum (Osteichthyes)
Pelvic fins
Bilaterally paired posterior fins, typically located in the posterior half of the body along the ventral (lower) margin
Dorsal fin
Usually one or two fins located medially (along the midline) along the dorsal margin of the body
Adipose fin
Present in some groups, the adipose fin is a small fleshy lobe located behind the dorsal fin and anterior to the caudal fin.
Anal fin
A single median fin located on the ventral (lower) margin of the body named for its proximity to the anal pore
Caudal fin
A single median fin located at the posterior of the vertebral column (tail fin)
Heterocercal caudal fin
Larger upper lobe
Homocercal caudal fin
Two lobes equal size
Hypocercal
Large lower lobe
Diphycercal
Single undifferentiated lobe
Caudal peduncle
Fleshy base of the caudal fin
Terete body form
Cylindrical or oval in cross section and tapered at both ends
Typically fast moving fishes in open water
Compressed body form
Laterally (side to side) flattened shapes that are tall and narrow
Typical of slower moving fish that inhabit highly structured habitats like coral reefs or weed beds
Depressed body form
Flattened shapes that are short and wide
Typical of bottom dwelling or sedentary species
Anguilliform
Lateral undulations that move from head to tail.
Typical of long, thing fish that move relatively slow
Carangiform
Lateral undulation are restricted to the posterior half of the body
Typical of terete shaped fish with faster movements
Ostraciiform
Undulations are restricted to the caudal peduncle and fin due to to an inflexible body
Limited to fishes with an extremely rigid body
Labriform
Movement through flapping motion of pectoral fins
Typical of wrasses and other fish who rely on a lot vertical movement in complex three dimensional habitats like coral reefs
Balistiform
Coordinated undulations of the dorsal and anal fins created forward and backward movement. Typical of triggerfish and other that rely on anterior-posterior movements in complex three-dimensional environments like coral reefs
Buoyancy organs
The oily liver of chondrichthyans or gas filled swim bladder of actinopterygians
Viscous drag
The frication created the surface of the fish/s body and the water surrounding it
What type of fish have high viscous drag
Long thin fish due to the high surface area and low volume
Traits of fish to reduce viscous drag
Smooth scales and/or producing oils and mucous to coat the scales
Inertial drag
Pressure differences created by the displacement of water as a fish moves