Can someone tell me the difference between P. orbignyi and P. humerosus?

[PoopSmart]

I looked up one (humerosus), and then I found the other. THen I looked up P. orbignyi and I found it to be called the smooth black river stingray (which I thought was a reticulated ray and the pictures look just like a retic).

Can someone please shed some light on this for me? I just found a P. humerosus in stock at cichlid exchange and thats why I was wondering what it was.

 

[Miles]

Orbignyi has a smooth back, and Humerosa doesn't?

I think there is more to it though, let's see what other's say..

 

[PoopSmart]

Well bigdavesrays said the exact same thing Miles, so I guess I can only tell in person. I will have to cop-a-feel and the orbignyi should have a smooth back (smooth black river stingray) and the humerosa won't.

 

[Nic]

I think the pattern is more defined on one of them too.....