3 Classes down 2 more to go Myxini

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3 Classes down, 2 more to go • Myxini (hagfishes) • Petromyzontida (lampreys) •

3 Classes down, 2 more to go • Myxini (hagfishes) • Petromyzontida (lampreys) • Chondrichthyes (sharks, rays and chimaeras) – How many?

What do you think? • Is the lancelet a fish? Fish-like characters of lancelets

What do you think? • Is the lancelet a fish? Fish-like characters of lancelets -myomeres -nerve cord -post-anal tail -notochord -pharyngeal slits (gills? ) *Compare to lamprey ammocoete

Where are we? Phylum Chordata Lancelets- Subphylum Cephalochordata Everything else- Subphylum Craniata

Where are we? Phylum Chordata Lancelets- Subphylum Cephalochordata Everything else- Subphylum Craniata

What are we? What makes a craniate? -cranium -red blood cells -bone (or cartilage)

What are we? What makes a craniate? -cranium -red blood cells -bone (or cartilage) What makes a vertebrate? -vertebrae -dermal bones -neural crest

Hagfish vs. Lamprey • Compare and contrast the specimens Shark inner ear has 3

Hagfish vs. Lamprey • Compare and contrast the specimens Shark inner ear has 3 semicircular canals

How are they related? Cyclostome Hypothesis Vertebrate Hypothesis For now, lampreys considered basal to

How are they related? Cyclostome Hypothesis Vertebrate Hypothesis For now, lampreys considered basal to vertebrates But. . Compelling evidence exists that supports the cyclostome hypothesis Relationships are uncertain!

We covered the jawless fishes What next? . . . Jawed fishes Superclass Gnathostomata

We covered the jawless fishes What next? . . . Jawed fishes Superclass Gnathostomata

Class Chondrichthyes • Subclass Holocephali (etymology? ) – Chimaeras • Subclass Elasmobranchii – Sharks

Class Chondrichthyes • Subclass Holocephali (etymology? ) – Chimaeras • Subclass Elasmobranchii – Sharks – Skates and Rays

Chondrichthyan characters • • Cartilaginous skeleton Fin “rays” called _______ No gas bladder Oily

Chondrichthyan characters • • Cartilaginous skeleton Fin “rays” called _______ No gas bladder Oily liver Spiral valve intestine Claspers Ampullae of Lorenzini

Differences Holocephali Jaw fused Ever-growing toothplate Scaleless No cloaca (? ) Elasmobranchii Jaw protrusible

Differences Holocephali Jaw fused Ever-growing toothplate Scaleless No cloaca (? ) Elasmobranchii Jaw protrusible Serially replaced teeth Placoid Scales Cloaca

Sharks vs. Rays • Division Neoselachii – Subdivision Selachii – Sharks • Pectorals not

Sharks vs. Rays • Division Neoselachii – Subdivision Selachii – Sharks • Pectorals not fused to head • Some with anal fin • Gill slits lateral – Subdivision Batoidea – Rays and skates • Pectorals fused to head • No anal fin • Gill slits ventral

Videos • http: //animal. discovery. com/videos/mutual-of -omahas-wild-kingdom-manta-rayfingerprints. html http: //www. youtube. com/watch? v=rs. FVDm.

Videos • http: //animal. discovery. com/videos/mutual-of -omahas-wild-kingdom-manta-rayfingerprints. html http: //www. youtube. com/watch? v=rs. FVDm. Fv. Rbg

Shark Lab 1. What does Gnathostomata mean? And what taxonomic level is it? 2.

Shark Lab 1. What does Gnathostomata mean? And what taxonomic level is it? 2. How do you tell gender of shark, ray or chimaera? 3. How do you tell a shark apart from a ray (harder than you may think)? 4. Terms (what they are and what they look like): palatoquadrate, ceratotrichia, Ampullae of lorenzini, placoid scales 5. Know how to identify all orders (families for Myliobatiformes). Know names of representative families. 6. 2 differences between Holocephali and Elasmobranchii