Pterosaurs, whose name means “winged lizards,” began during the Triassic but really took off during the Jurassic. They were the first vertebrates to attain true flight, and while they are often called flying dinosaurs, they are not closely related to either dinosaurs or birds. Their descent within the reptiles is ultimately from some basal archosaur, but because of poor and sporadic preservation, their ancestry is not well understood.
The wing-flap in pterosaurs was stretched over a greatly extended fourth finger. Bats, in contrast, have all their digits extended.
|Rhamphorhynchus image source: Picture by M0tty or Antoine Motte dit Falisse, used under Creative Commons license.|
There are more than 30 different genera of Jurassic pterosaurs, so they were quite diverse. Most were relatively small, with wingspans of a few feet. There’s been a lot of analysis to try to separate small pterosaurs from juvenile versions of larger species, and there probably were some pretty small pterosaurs, the size of small birds like sparrows.
Geographically, Jurassic pterosaurs have been found on every continent, although they are quite rare in Australia and Antarctica – but whether that is a measure of their distribution or lack of appropriate sediments to preserve their fossils is unclear.
Next month, the Cretaceous, we’ll revisit pterosaurs because that’s when they became gigantic, the largest flying animals in earth’s long history.
If you are in New York, there is an exhibit at the American Museum of Natural History on pterosaurs. It runs through January 4, 2015.
—Richard I. GibsonLINKS:
Rhamphorynchus life story
Rhamphorhynchus image source: Picture by M0tty or Antoine Motte dit Falisse, used under Creative Commons license.