Lab #1 Intro Flashcards
Allometric growth
Changes in body proportions as they grow
Non-discrete variables
Variables that are continuous
Total Length
Straight line distance from anterior to tip of caudal fin when lobes are pinched
Standard Length
Straight line distance from anterior tip to end of the vertebra at the base of caudal fin
Can only be measured in fishes with homocercal caudal fins
Homocercal
straight and vertical free border
Dorsal and ventral lobes of equal size
Hypural plate
the internal structure that marks the end of the vertebral column
Bend caudal fin at its base, causes a crease (locate the hypural plate)
Snout-vent length
From tip of the snout to the opening of the anus
Fork Length
From the tip of the snout to the fork of the caudal fin
Head length
From tip of snout to end of operculum
In Chondrichthyes to last gill
Maximum depth of body
Vertical length (no fins) normally 1/3 down the body
Minimum depth of caudal peduncle
minimum height of trunk region between anal fin and caudal fin
Head length to standard length
Useful diagnostic ratio for many taxonomic keys
Meristic variables
discrete variables that are counts (fin counts)
Spiny Rays
Stiff and sharp
Unsegmented and unbranched
Most anterior
Heavy spinous rays
stiff often with sharp barbs on posterior
thickened and hardened soft rays
Soft rays
branched and clearly segmented
occur on the posterior portion
Scales above the lateral line
first scale anterior to dorsal fin going in an oblique row to the lateral line
scale rows below the lateral line
starting anterior continuing angled up towards lateral line
Scales on lateral line
number of scales lying on the lateral line from the shoulder girdle to the end of the hypural plate
Snout
with external nares. nostrils usually have no connection with the oral cavity, only sensory organs no respiratory function
Eyes
Most fishes have no moveable eyelids. A thin cornea covers the outer surface
Spherical lens, retina and choroid forming layers in back of eye
Mouth
The margin is called the gape. Either of two bones maxilla or premaxilla
Caniniform
(needle like)
are pointed, elongated and narrow in appearance
Incisoriform
(blade like)
have sharp cutting edge, with broad base
Molariform
(millstone-like teeth)
blunt or flattened, stout for grinding and crushing
Tongue
lying in the floor of the mouth, cartilaginous or bony structure
Taste receptors
Operculum
thin lid-like structure covers and protects the gill openings
Branchiostegal rays
parallel, bony struts, arranged like ribs of bellows of a fan
connect membranes of two sides of lower jaw
Isthmus
The skin connecting the two sides of the lower jaw on the ventral side of the head
Free/Seperate Isthmus
Not joined to the isthmus or each other (smelts)
United
Joined to each other across, but not to the isthmus as in sculpins
Joined
attached to the isthmus (pricklebacks)
Gular plate
a flat, blade-like bone that lies within the skin of the ventral side of the head
serving mainly a protective function
Barbels
fleshly, hair-like projections on the chin or around the mouth
They have sensory functions
Paired Fins
Pectoral fins
Pelvic fins
Unpaired fins
Dorsal fins
Finlets
Anal fins
caudal fins
adipose fin
Placoid scales
dermal denticles
unlayered, tooth-like scales (sharks etc)
Ganoid scales
heavy plate-like scales forming bony armour
ancestral fishes (gar)
cycloid scales
thin round flat overlapping scales
soft rayed fishes (salmon/trout)
ctenoid scales
similar to cycloid but they have comb-like projections on exposed edge
spiny rayed fishes (perch)
Myomeres
Theses w-shaped blocks of axial muscles
Physotomous condition
swim bladder is connected to mouth by a duct
This is ancestral
Physoclistous condition
this connection from bladder to mouth is lost
Otoliths
bioorganic minerals of protein and calcium carbonate (not bone)
Used for sound
Three otoliths in fish
lapillus, asteriscus and sagitta
Fusiform
Spindle-like and elongate (lingcod)
Anguilliform
eel-like, greatly elongate (lamprey)
Ovate
Truncated (shortened) (clingfish)
Compressiform
compressed, thin and narrow, deep (perch)
Depressiform
Depressed, flattened (skate)
Globiform
subcircular, hemispherical (pufferfish)
Gnathostomata
Jawed vertebrates
Chondrichthyes
cartilaginous fishes
Elasmobranchii
Sharks, skates and rays
Holocephali
chimaeras (ratfishes)
Only cartilage fish with bony gill cover
