Pterosaurs were flying
reptiles of the clade or order Pterosauria. They existed from
the late Triassic to the end of the Cretaceous Period (220 to
65.5 million years ago). Pterosaurs are the earliest vertebrates
known to have evolved powered flight. Their wings were formed
by a membrane of skin, muscle, and other tissues stretching from
the legs to a dramatically lengthened fourth finger. Early species
had long, fully-toothed jaws and long tails, while later forms
had a highly reduced tail, and some lacked teeth. Pterosaurs spanned
a wide range of adult sizes, from the very small Nemicolopterus
to the largest known flying creatures of all time, including Quetzalcoatlus
and Hatzegopteryx.
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The
pictures of pterosaurs are organised by group (Pterodactyloidea
and Rhamphorhynchoidea) on these tabbed pages. |
Pterodactyloidea (meaning "winged
finger", "wing-finger" or "finger-wing")
forms one of the two suborders of pterosaurs ("wing lizards"),
and contains the most advanced members of this group of flying
reptiles. They appeared during the middle Jurassic Period, and
differ from the basal rhamphorhynchoidea by their short tails
and long wing metacarpals (hand bones). The most advanced forms
also lack teeth. Many species had well developed crests on the
skull, a form of display taken to extremes in giant-crested forms
like Nyctosaurus and Tupandactylus. Pterodactyloids
(specifically the family Azhdarchidae) were the last surviving
pterosaurs when the order became extinct at the end of the Cretaceous
Period, together with the dinosaurs and most marine reptiles.
The Rhamphorhynchoidea forms
one of the two suborders of pterosaurs and represent a grade of
primitive members of this group of flying reptiles. This suborder
is paraphyletic in relation to the Pterodactyloidea, which arose
from within the Ramphorhynchoidea, not from a more distant common
ancestor. Because it is not a completely natural grouping, Rhamphorhynchoidea
is not used as a formal group in most scientific literature, though
some pterosaur scientists continue to use it as an informal grouping
in popular works, and in some formal studies. Ramphorhynchoids
were the first pterosaurs to have appeared, in the late Triassic
Period. Unlike their descendants the pterodactyloids, most rhamphorhynchoids
had teeth and long tails, and most species lacked a bony crest,
though several are known to have crests formed from soft tissue
like keratin. They were generally small, and disappeared at the
end of the Jurassic Period.
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