Pterosaurs arise in the fossil record about 210 million years ago. For the next

Question

Pterosaurs arise in the fossil record about 210 million years ago. For the next 55 million years, most were built like Ramphorynchus (see Fig. 2.33a in text). They had long tails and relatively small skulls with two separate openings called the anorbital fenestra and the nasal fenstra (orange arrows on the photo). They had neck ribs and elongated fifth toes. Pterodactyls first appear about 150 million years ago. Within 30 million years they replaced all earlier pterosaurs and then persisted until 65 million years ago—when they went extinct along with all the other dinosaurs. Most pterodactyls had short tails and large skulls with a single nasoantorbital fenestra (see Fig. 2.33b in text). Their neck ribs and fifth toes were reduced or absent. Detailed anatomical analyses present results consistent with the macroevolutionary hypothesis that pterodactyls derive from an earlier lineage of pterosaurs, and from this we predict that the fossil record should contain flying reptiles intermediate in form between the early pterosaurs and later pterodactyls.  Write down your prediction of what these transitional forms should look like, and the age of the rocks in which they are most likely to be found. Then look at the photos of Darwinopterus modularis in this article. How old do paleontologists say these fossils are? Were your predictions about the fossils’ appearance and age correct?

http://rspb.royalsocietypublishing.org/content/early/2009/10/12/rspb.2009.1603

textbook: evolutonary analysis

Explanation / Answer

Early Pterosaurs belong to the Ornithodirans, the stem group of dinosaurs and birds. There are obvious differences in the leg and ankle structure from both the crocodiles and the dinosaurs and birds - not to mention the modifications to the arms to form wings. There is a unique bone in the arm that connects the wrist to the propatagium, a part of the wing that serves roughly the same function as the alula in birds’ wings.

The pterosaur was discovered in rock that's about 160 million years old.

Although pterosaurs lived during the dinosaur age, known as the Mesozoic era, they were not dinosaurs themselves. Rather, pterosaurs were flying reptiles — the first flying vertebrates on record by the researchers.

Later pterodactyls had a long beak filled with around 90 small, sharp teeth. The rest of its head was small. Unlike earlier pterosaurs, whose tails were long and thin, Pterodactylus had a very short tail.

It’s likely that the heads and bodies of some pterosaurs were wholly or partially covered with fur, but it is unknown if this was present in pterodactylus.

Pterodactylus had a crest on the top of its head. It is thought that this crest grew as the pterodactyl aged, and was a sign of maturity.

Pterodactyls were prevalent during the Mesozoic Era between 220 and 65 million years ago.

Fossil of later pterodactyls aremostly been found in the Bavaria region of Germany they are 150 million years ago.

Fossil of early pterosaur are 215 million years ago.

According to my estimated calculation on prediction on the fossils appearance and age correct is right.

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