Did you know fantastic help is an anagram of Planet Catfish? This forum is for those of you with pictures of your catfish who are looking for help identifying them. There are many here to help and a firm ID is the first step towards keeping your catfish in the best conditions.
Yes it is R. platyura. I also caught this species in French Guyana, and in Guyana in the Essequibo. One of my co-workers caught some in the Guama, Heiko Bleher gave me a specimen from the Purus, and I saw pictures of a specimen from the Mamore last week. So it can be a representative of this species (or maybe species complex). R. platyura is descibed from the Rupununi which has connections with the Rio Branco (via the Takutu River).