Just because I <3 you, here are links to Josh's Frogs sexing guides 
Josh’s Frogs How-To Guides » Blog Archive » How to Visually Sex Dart Frogs
Josh’s Frogs How-To Guides » Blog Archive » How to Visually Sex Dart Frogs Part II
Josh’s Frogs How-To Guides » Blog Archive » How to Visually Sex Dart Frogs
Josh’s Frogs How-To Guides » Blog Archive » How to Visually Sex Dart Frogs Part II