Fish Bio Review #1
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Fish Bio Review #1
What is in the superclass agnatha?
lamprey and hagfish are living representatives
What are the tree characteristics of the phylum chordata?
Hollow, dorsal nerve chord
What types of fishes are in Gnathostoma?
Order Myxiniformes - modern hagfish
Order Petromyzontiformes - modern lamprey
‘Ostracoderm’ includes two important Classes:
Class Cephalaspidomorphi = ancestor to lamprey??
Class Pteraspidomorphi = ancestor to hagfish??
• Ostracoderms now extinct
What classes are found in the superclass Gnathostomata?
Class Placodermi - plate-skinned (extinct)
Class Acanthodii - spiny sharks (extinct)
Class Sarcopterygii – lobed-fin fishes
Class Chondrichthys - sharks, skates, rays
Class Actinopterygii - ray-finned fishes
What did this animal have on its head and shoulder?
- Head and shoulder girdles with dermal bony plates joined by Craniovertebral joint which allowed it to move.
Arthrodire- "jointed neck"
What is this and what is it most closely related to?
Acanthoidian- extict class of fish
More closely related to modern day bony fish than sharks, even though skeleton was mostly made of cartilage.
What are some of the features of the
Fins broad-based and stiff,long radial elements
No anal find.
Caudal fin is homocercal
Body supported by notochord only
Often spines in front ofdorsal, pectoral, and pelvic
Describe some Hybodont Features
- Fins flexible and mobile
-Caudal fin heterocercal
-Body supported by notochord
with neural arches
- Spines on dorsal fin
What are the four things that the third elasmobranch radiation that allowed improved feeding and locomotion?
: ventral mouth with protrusible upper jaw
: tooth replacement system
: ceratotrichia supporting the fins
: calcified vertebrae instead of notochord
What are the two subdivisions of Infraclass Euselachii?
Subdivision Selachii (sharks - 9 Orders)
Subdivision Batoidea (rays - 4 Orders)