Amero-Australian Treefrogs: Hylidae
The many species of Amero-Australian treefrogs often appear very different from one another. Inside their bodies, however, they have similar skeletons. For example, the set of bones on one side of the chest overlaps with the set on the other side, and the bones at the tips of the toes are shaped like claws. From the outside, most of the treefrogs have slender bodies, long legs, and wide toe pads that may be round or triangular-shaped. A few of them have plump bodies and short legs, and some have no toe pads. Most have webs that reach at least halfway up their rear toes. Webbing on the front toes is present in some species, but not in others.
All of the Amero-Australian treefrogs have teeth on the top of the mouth. Only a few have teeth or teethlike bones on the bottom of the mouth. Most have a round eardrum that shows on each side of the head. Some have smooth, shiny skin, but others are covered with small bumps. A few, like the horned treefrog, have large heads, small spikes above their eyes, and two large points on the top of the head that might be mistaken for ears or horns.
Most of the frogs in this family are green or brown with dark markings. These camouflage colors and patterns help them to blend in with their surroundings. Their undersides are typically light in color, sometimes with light brown, brown, or black marks. Many have bright patches on their sides and/or the insides of the hind legs. The red-eyed treefrog, for example, is a lime green frog with sides that are each colored with a set of large blue areas separated by thin white to yellowish lines. A few treefrogs, such as the Chachi treefrog, are very colorful on their backs, too. This frog is yellow with a detailed pattern of red to reddish brown on its back and head.
Depending on the species, Amero-Australian treefrogs may be as small as 0.8 inches (2 centimeters) from the tip of the snout to the end of the rump or as large as 4.8 inches (2 to 12 centimeters). Males usually look similar to females, but commonly are smaller and may have bright yellow or dark gray vocal sacs. In addition, most males have rough patches and occasionally spines that form on their front legs and/or feet during the breeding season. These patches are called nuptial (NUHP-shul) pads and help the male hold onto the female during mating.