Presentation on theme: "Phylum Chordata Class Chondrichthyes Order Rajiformes Family Rajidae"— Presentation transcript:
1Phylum Chordata Class Chondrichthyes Order Rajiformes Family Rajidae Skate DissectionPhylum ChordataClass ChondrichthyesOrder RajiformesFamily Rajidae
2More about our specimen: While it may not seem like it, sharks and rays (the skate is in a subgroup of rays) are very closely related. They both fall into the class chondrichthyes.External anatomy differs greatly, but internally and developmentally, sharks and ray are almost identical.Inexpensive and easy to cookWe can try to say that they’re cute, but that’s a stretch.
3Sketch 1Only label the circled terms. Note the fins, they all exist on a ray just like they do on normal fish, only they’ve been adapted for the rays unique lifestyle.If it is a male
4Sketch 2See if you can spot the ampullae of Lorenzini. When you find them, label them also. (They are not pictured here)If it is a male
5Sketch 3Carefully open the gut below the gill openings on the ventral side of the skate.First, note the large liver with reproductive organs on either side (if a male).Draw a picture of the liver/gonads and then remove them to reveal the digestive organs underneath.
6Also, note the intestine running to the anus. HeartSketch 4Next, remove the liver to reveal the 2 stomachs (pyloric on the left, cardiac on the right). Draw a quick sketch of these organs.Lifting the cardiac stomach will reveal the spleen (dark sac on stomach) and the kidney (brown organ on the right)And the uterus/ovary if female….If male, parts (testis) will looks smallerAlso, note the intestine running to the anus.
7Sketch 5Just like with the bony fish, be careful and try not to destroy the brain while opening the head.Using scissors, cut open the head region between the eyes to reveal the brain.
8You’re all done with sketches…… If you have any other areas you want to explore, feel free.Dissecting scopes are on the front table if you want to view anything at a high magnification.