This is my identification check list - most pterosaur teeth will exhibit these features.
- Evenly curved and consistently tapering tooth.
- Wear bevel at the top smooth with no abrasions.
- Enamel cap at the crown.
- Fine striations may be present towards the base of the tooth.
- Open root.
If the tooth does not conform to this type, then the only sure way to know that it is a pterosaur tooth is for it to be fixed within a fragment of fossil jaw bone where the bone structure can be determined.
Most pterosaur teeth are evenly oval in cross section and generally of smooth appearance. There are some exceptions, like the tricuspate teeth of the very early pterosaur species. Specialist feeders like Dsungeripterus and Pterosdaustro, but the shapes of these exceptional teeth are well documented.
The moral of this post is - if you are buying an isolated pterosaur tooth, expect it to be non-pterosaur unless it has provenance and an expert opinion attached. It is also unwise to buy a fossil unless you know the locality, sediment and age of the site that it came from.