"Could this be the Moema pepotei that Costa described in 1992?
The species was described from a single specimen in very poor condition collected 1962 by Walford and Bokerman near Forte Principe da Beira, Rondonia - Brazil, beside the Iténez / Guaporé river. There are only a few reports of this species in Brasil and Bolivia, and its morphology and coloration in life remains a mystery until now.
The specimens in this photos were also collected near the Iténez / Guaporé river, but almost 250 km upstream from Forte Principe da Beira." - Hein Arno Drawert, 2021.