Going off of jaw structure and spot I am leaning twards Microlepis. I had 2 of these some years ago that were Ided by Tom lorenz on pfury as such. And they are a good one to have. Sort of like a Falcirostris But a little smaller and much deeper bodied when bigger. Mine got to around 11" in the couple of years I had them.
http://www.angelfire.com/biz/piranha038/images/guianensis_Head_Lorez.jpg
http://www.angelfire.com/biz/piranha038/images/guianensis_Head_Lorez.jpg