Lecture 7. September 10, 2008 1. Shark Conservation 2. Actinopterygii vs. Sarcopterygii 3. Coelacanth story. 4. Details on Coelacanth & Lungfishes

Fish in the News! http://www.msnbc.msn.com/id/26604743/?GT1=43001

shark conservation direct targets of fisheries - two examples porbeagle soupfin sharks

shark conservation sharks as by-catch

Blue Shark - Common by-catch in swordfish fisheries

Discerning Characters of Sarcopterygii vs. Actinopterygii

Fleshy, lobed pectoral, pelvic, anal and second dorsal fin Fins can rotate 180 degrees lobed, fleshy parts go up into fins

Bony leg-like supports, external to body Class Sarcopterygii Lobe fins Bony leg-like supports, external to body Pectoral fin Pelvic fin

Class Sarcopterygii Three major living groups Coelacanthimorpha-coelacanths (two species) Dipnoi-lungfishes (six species) Tetrapoda (all non-fish vertebrates)

Class Sarcopterygii Osteolepimorpha - extinct Coelacanthimorpha Tetrapoda Dipnoi

Order Coelacanthiformes Fossil record extends from M. Devonian (370 Ma) to Cretaceous (65Ma) This 65 ma date is noteworthy, because for a long, long time it was believed that this group of fishes died out - about the same time dinosaurs disappeared However, in 1937…..

Order Coelacanthiformes Marjorie Courtenay-Latimer In 1938 A young curator of a small museum in East London South Africa was looking through a pile of fish brought in by a fisherma. She instantly recognized something very different

She bought the specimen, which was about 4 feet in length made these drawings and notes sent them to J. B. L. Smith, who at the time was the most active Ichthyologist in Africa. The rest is history..

Order Coelacanthiformes Smith describes the coelacanth, Latimeria chalumnae, discovered in 1939, a true living fossil

Teeth 0n hard Bony plates plates Diphycercal tail Why is it living fossil, just look at Courney-Latimer’s drawing… Bony armor around head Diphycercal tail And I know its tough to read but she lists here teeth in hard plates Remind you of anything??? PLACODERMS

The description made news around the world What was now needed were more specimens..

A rewar of 100 pounds ($280) was put out to anyone who collect another specimen A lot of money in those days,….. Smith and many others began a searching all of the waters and fishing markets of Southern Africa Finally, in 1952 he received word that another specimen had been caught in the Comores Islands NW of Madagascara about 1700 miles north of where the first specimen was captured

This is a pic. Of Smith with that second specimen. You’ll notice in this picture that these other gentlemen in the background look like naval or air force officers. They are. This just give you an example of how big a scientific discovery the coelacanth was. When Smith got word of this second specimen, he was flown the next day by the Air Force up to the Comores Islands. The chances of getting that kind of service today are next to zero. From 1952 on, specimens of coelacanths are collected with some regularity by fishermen using deep trawls

Marjorie Courtenay-Latimer Brass plate at Latimer's Landing East London.

Order Coelacanthiformes “New” populaiton discovered at Sulawesi, Indonesia 1997 Found in a fish market by a zoologist who just happened to be in Sulawesi on his honeymoon.

Order Coelacanthiformes “New” populaiton discovered at Sulawesi, Indonesia 1997 DNA analyses indicate divergence from L. chalumnae at 5.0-11.0 Ma Described as a new species L. menadoensis One of the first (maybe only) example of a new species being described on the basis of molecular data rather than observable morphological differences

Order Coelacanthiformes

Order Coelacanthiformes Symmetric three-lobed tail Distal end has an epicaudal lobe

Order Coelacanthiformes Oil filled gas (swim)-bladder Craniovetebral joint (Placoderms also have these) Increase gape

Coelacanth Biology Lives along rocky shelves in deep (150 to 300 m) waters Lurking predator, feeds on molluscs, fishes, and cephalopods Stands on head while swimming, uses paired fins as paddles Internal fertilization, ovoviviparous Nocturnal predator Can reach a very large size - 2.5 m Ovoviviparous - females have very large eggs (largest known for fishes) that “hatch” internally, young develop with yolk sacs in uterus

Coelacanth “head standing” http://www.youtube.com/watch?v=rYOf2wIoxgo

Class Sarcopterygii Osteolepimorpha - extinct Coelacanthimorpha Tetrapoda Dipnoi

Obligate Air-breathers Divided lungs Facultative Air-breather Unpaired lung

Order Ceratodontiformes - Australian lungfish

Order Ceratodontiformes - Australian lungfish

Order Ceratodontiformes - Australian lungfish Neoceatodus forsteri Southeast Queensland, Australia Facultative air-breather, rely on gills

Order Ceratodontiformes - Australian lungfish Neoceatodus forsteri can reach a very large size

Order Lepidosireniformes Pectoral and pelvic fins filamentous, without rays Obligate air breathers - rely on lungs, will drown if it can’t reach the surface

Order Lepidosireniformes Dig burrows with mouth Secrete a mucus that will encase the body and prevent moisture loss

Order Lepidosireniformes Dig burrows with mouth Secrete a mucus that will encase the body and prevent moisture loss

Order Lepidosireniformes Family Lepidosireneidae - S.A. lungfish Lepidosiren paradoxa

Order Lepidosireniformes Family Protopteridae - African lungifsh Protopterus - 4 species

S.A. Lungfish Video http://www.youtube.com/watch?v=2sDjC6DMmZ4

Review Questions 1. Draw the phylogenetic tree with the following groups: Myxiniformes, Petromyzontiformes, Gnathostomata, Holocephali, Elasmobranchii, Chondrichthyes, Osteichthyes, Actinopterygii, Sarcopterygii. List the traits that define each of these groups. 2. Why was the discovery of the Coelacanth surprising and why were people in the 1800’s excited by the finding? How many species of coelacanth are there? What is the evidence for 2 separate species? 3. According to your book, which group of living fish are most closely related to the tetrapods. Who were the Osteolepimorphs? Why are they important to our understanding of the evolution of vertebrates? 4. Name the two orders and three families of lungfishes. List 2-3 traits of each. Which families are obligate air breathers? What does it mean to be an obligate air breather? Which family aestivates? Where is each family found? 5. Compare and contrast Coelacanths and Lungfishes in terms of reproduction, presence/absence of lungs, presence/absence of oil filled swim bladder, and properties of the caudal fin.

Review Questions (Cont’d.) 6. How do Coelacanths use their fins? Who was Jim Smith? Why was his use of the term “old four legs” a bit misleading? 7. Who are “Ceratodontiformes” and “Lepidosireniformes”? Where do they live? To what extent does each rely on its lungs (vs. its gills) for oxygen. Which group aestivates? What do fish do when they aestivate? Compare and contrast them in terms of body shape and pectoral and pelvic fin structure.