okay please don't blame any nerd-gasims or fits of anger but I'm about to break down the dragon family tree for those who simply don't know.
Dragons- body can be snake like, lizard like, or humanoid. limbs must include; tail. forelegs, hind legs, and wings
Eastern Dragons- snake like body structure (can include humanoid forms to some extent but must still retain a serpentine grace to to means of flight) often with manes and antler like horns; flys by a mixture of lighter-than-air gas bladders and magic (this is what gains them their dragon classification): limbs include; fore legs, hind legs,vestigial wings, and tail.
Drakes- body can be snake like, lizard like, or humanoid: can not fly with out mechanical help: limbs include; fore legs, hind legs, vestigial wings, and tail.
Wyvwerns- often confused with dragons they tend to be more territorial and less inclined to horde (dragons can often be found living happily as family groups or even clans but wyvwerns attack any large creature that enters their territories) they also tend to be less intelligent and to use bathroom habits to give them selves strong scents that they use for border marking (EEEEEWWWW >.<): body; snake like, lizard like, and humanoid (the humanoids tend to break the smelly and stupid habits of the more feral forms): limbs include; wings, hind legs and tail.
Wyrms- often confused with nagas (who are unrelated to the dragon family) they have a snake like form and fore legs only (they can hover a few feet off the ground by magical means), major distinguishing factors between them and the nagas are; the dragoniod shape of head including horns on the males and wing ear flaps on both sexes, climatic locations of choice (while most nagas like dry sandy regions, wyrms prefer forests and swamps digging homes in dryish locations within these settings), and armoring (the naga has snake scales while Wyrms have classic dragon armor scales)
Serphants- snake like in form often with the classic dragon head though some may have more snake-like heads:limbs include. wings (often the wings of serphants are feathered), and in some rare instances fore limbs are included.
Hydras- multi-headed drakes or wyrms always seem to suffer from multi-personality disorders, must have more than three heads to qualify and a bad habit of growing two for every one lost, (when one head becomes murderously angry the heads often multiply out of control) heavily regenerative. (tip of the day they don't do so well if dropped into a volcano or burned until black and crispy) they always seem to have at least one head that is supper annoying.