A. Catfish- Is this a ray-finned or lobe-finned fish? Sketh/lable or describe th

Question

A. Catfish- Is this a ray-finned or lobe-finned fish? Sketh/lable or describe the difference

B. Exaimine the illustration, casts, and sculptures at this station(e.g. Protoceratops, velociraptor, oviraptor cast of egg, sculpture of egg with embryo, phto of fossil skeleton sitting on a nest with eggs, pointing of same scene) These are trade mark dinosaurs of the Flaming Cliffs of Djadochtha and fossil beds at Ukahaa Tologd in Mongolia. Describe what we have nearned about dinosaur reproductive behavior.

Explanation / Answer

A. Catfish are a diverse group of ray-finned fish. The ray fin fish are the most susuccessfulroup of vertebrates, at least in the water, but also as a whole with an incredible diversity, biomass and growth rate.

The lobed fin fish have a bone structure comparable to ours with shoulder, upper arm, lower arm and finger bones. Also they have sacks on the gut or even lungs. With Coelacanths these sacks are filled with fat I thought, because lungs are not much use in their enenvironmentt 150 meters depth.

Ray-finned fishes have fins that are covered by skin only, and the fins are supported by a number of thin bony rays or spines. These rays are attached to a bony base at the body. Lobe finned fishes have paired dorsal fins, but ray finned fishes have only a single dorsal fin. Lungs first evolved in an early fish. They are retained in at least some lobe-finned fishes, but they have evolved into the swim bladder in ray-finned fishes.Another 27,000 species make up the ray-finned fish.

B. All dinosaurs laid eggs either in a protective hole or some form of mound-like nest structure, though these are thought to have differed in complexity between species.

Sauropods dug out their nests, laid eggs inside, and probably didn't stick around to hatch them. At the other extreme, fossils discovered in the US indicated that herds of the duck-billed, ornithischian herbivore Maiasaura ("good mother lizard") built extensive nesting colonies in the earth, then laid batches of around 10-15 eggs (each 10-12cm long), evenly spaced within the nest.They were also found to have fed their new hatchlings in the nest, the first evidence of such behaviour among larger dinosaurs. Similar behaviour is believed to have occurred among theropods.

Non avian dinosaurs were probably sexualy dimorphic and some may have engaged in hierarchial rituals. Non avian coelurosaurs had two oviducts, each produced a single egg on a daily or a longer basis.The eggs were incubated in soils, whereas eggs of non avian were incubated with combination of soil and direct parental contact.Parental attention to yong was variable , ranging from protection to predators to possible parental feeding of nest bound hatchlings.

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