Chondrichthyes Flashcards
Chondrichthyes Features
cartilage skeleton
7cm - 13 m
mainly hylostylic jaw
paired fins
1-2 dorsal fins
claspers, 4-7 gills
spiracles (1st gill arch)
placoid scales
teeth in gums (replaced)
unsegmented fin rays
no swim bladder or lung
Spiral valve intestine
Almost all marine
Hyperosmotic: use urea
Reproduction: oviparous, ovoviviparous, viviparous
Large body mass to brain ratio
Holocephali
Chimaeriformes (ratfish)
Large green eyes, nocturnal
Very derived – upper jaws fused
gills under single flap
nostril bleeding
wing like pectorals
Galeomorphii
Salmon, Pacific Blue, Basking Shark, Thresher, Mako, Soupfin, White all exist in BC
Aggregation of sharks North of Vancouver Island (~20 000)
White Shark Migration
They travel far stretches across the open ocean
During this time they dive to depths of 1000m many times during a day
Basking Shark Migration
Travel over very expansive distances and dive into very deep depths likely to feed
Squaliformes
No anal fin
Dogfish used to be the most abundant shark (hunted for liver)
Eaten by 6-gill sharks
Greenland sharks: most north, poison flesh, sluggish and long-lived
Cookie Cutter Shark: mouth used to lock onto large fast-moving prey at night and take a chunk of flesh. Mimic green bioluminescence
Most bites on swordfish
Skates and Rays
Bottom dwellers
ventral gills
no anal fin
inshore waters and eat marine invertebrates
lay egg cases
14 species in BC
