My name is Leontina and i absolutely love it. I've only met one other Leontina through social media. It's very unique and I get compliments often - and the name Leontina is used in Sicilian/Italian culture as well, which isn't listed here. I'm Sicilian and I'm named after my Great-Grandmother.
I think it's more correct to say that Leontina is a feminine form of Leontinus, because the -ina part clearly refers to a diminutive form (so it's not just a 'femininization', because a mere 'feminization' of Leontius would have been Leontia).