Lecture 9. Monday, September 15, 2008.

1. Details on basal Actinopterygiiansa. bichirs - Polypteriformesb. sturgeon & paddle fish - Acipenseriformesc. gar - Semionotiformesd. bowfin - Amiiformes

2. Review material to date.

Class Actinopterygii - the ray-finned fishes

Polypte

riform

es

Acipen

serif

ormes

Semio

notiform

es

Amiif

ormes

Teleo

stei

Semiontiformes = Lepisosteiformes

Order Polypteriformes - bichirs

Polypteriformes

Order Polypteriformes - bichirs

• 5 to 18 separate finlets- each with a spine and soft rays

Unique characters

Order Acipenseriformes - sturgeons and paddlefish

Polypte

riform

es

Acipen

serif

ormes

Semio

notiform

es

Amiif

ormes

Teleo

stei

Family Acipenseridae - sturgeon

Family Acipenseridae - sturgeon

link to Carol’s website

Family Acipenseridae

Family Acipenseridae

= grave conservation situation, several species near extinction

Family Acipenseridae

• Sturgeons are the largest fishes found in freshwaters• beluga sturgeon -27 ft, 1,800 lbs.

• recreational fishery for more common species still a viable industry

sturgeon video

• http://www.youtube.com/watch?v=daoPehLwed8

Family Polyodontidae - paddlefishes

Family Polyodontidae

Family Polyodontidae

• Snout not developed in juveniles

Family Polyodontidae

• Two species

• Polyodon spatula - Mississippi River Drainage of eastern United States

•Psephurus gladius-China, Yangtze Drainage

Family Polyodontidae

• Polyodon spathula - biology

• Filter feeder, zooplankton, mouth non-protrusible

Class Actinopterygii - the ray-finned fishes

Polypte

riform

es

Acipen

serif

ormes

Semio

notiform

es

Amiif

ormes

Teleo

stei

Family Lepisosteidae

• Fossils

Order Semiontiformes - gar

Order Semiontiformes - gar

Range

Order Semiontiformes - gar

•Heterocercal tail

Order Semiontiformes - gar

•Vascular air bladder

Order Semiontiformes - gar

• habitat

Family Lepisosteidae - biology

• Spawn in late spring over shallow vegetated areas

• Female accompanied by multiple males, eggs broadcast over substrate

• Eggs are large, adhesive, & poisonous. Adhere to vegetation

• Larvae hatch with adhesive disk at tip of lower jaw, attach to vegetation until yolk sac is absorbed

Family Lepisosteidae - biology

•Reach maturity at 3 yrs, can live up to 20 yrs.

•Piscivores - lie-in-wait predators

•Most species average 2 - 3 ft. in size, alligator gar can reach 10 ft.

Family Lepisosteidae - biology

• Of seven known species, four known to occur in Illinois

spotted gar eating a fish

http://www.youtube.com/watch?v=BXuQL8HKgoE

Order Amiiformes

• One extant family, Amiidae

• one extant species - Amia calva

Order Amiiformes

• Amia calva

• Long dorsal fin, aids in propulsion

• Heterocercal tail

Order Amiiformes

Order Amiiformes

Amia calva - biology

• Life span ~10 years

• Can reach 2.5 - 3 ft. in length

Group Activity #1 -Draw the phylogenetic tree & distinguishing traits for:

group a - Myxiniformes, Gnathostomata, Chondrichthyes, Teleosts

group b - Petromyzontiformes, Elasmobranchii, Holocephali,Sarcopterygii, Actinopterygii

group c - Elasmobranchii, Holocephali, Sarcopterygii, Teleosts

group d - Myxiniformes, Petromyzontiformes, Chondrichthyes,Osteichthyes

Group Activity #2 - Rotate at least 2 nodes of the tree and draw it again.

Group Activity #3 - Design a dichotomous key that wouldallow one to distinguish these groups

For example . . .

Step 1 - lacks vertebrae --> Myxiniformesif not --> go to step 2

Step 2 - lacks jaws --> Petromyzontiformesif not --> go to step 3

Group Activity Number 4: Describe the general pattern in the evolution of the following:

group a - evolutionary transition from jawless to jaws

group b - evolutionary transition from no paired fins to pairedfins

group c - a possible explanation for the evolution of reproduction/offspring development in Elasmobranchii

group d - evolution of scales

Group Activity #5: For the same groups . . . describe the implications of these evolutionary transitions.

Group Activity #6 - Describe the evolutionary transitions of the following:

a) evolution of caudal fin shapes.

b) evolution of lungs/swim bladders.

c) evolution of the role of the maxilla and pre-maxilla in eating.

d) evolutionary loss of the spiral valve

What are the possible implications of these changes for fishes?

For each of the following taxa, list at least 3 details about their biology :

group 1: hagfish, Acanthodii, hammerhead, skates, basking sharkbichirs, black carp

group 2: lampreys, chimaeras, manta ray, electric rays,Coelacanth, sturgeon, common carp

group 3: Ostracoderms, whale shark, sting ray, great white, Australian lungfish, bowfin, grass carp

group 4: Placoderms, thresher shark, sawfish, megamouth, S.A. & African lungfish, paddlefish, silver & bighead carp