Otocinclus Species Id

[xautomaticflowersx]

I have a trio of Otocinclus, two of which are the same species but the third is very different. I've been looking on planetcatfish.com to try and figure out which species they are. I think that the pair who are the same are Otocinclus vittatus...

But I'm not sure which species this one is, kinda looks like Otocinclus mariae...

Any thoughts?

 

[xautomaticflowersx]

Anyone?