Identity and locality
Pseudancistrus nigrescens Eigenmann, 1912
Amatuk, Guyana (type locality); wider occurrence requires specimen-specific evidence
Diagnostic evidence and naming
The 2014 revision lists this named species among P. barbatus-group relatives. Snout odontode arrangement and spotted body characters are taxonomic diagnoses, not proof of artificial breeding grades. A separate catalog identifies Amatuk, Guyana as the 1912 type locality and an L299 trade association. It is not Tapajós P. zawadzkii.
Breeding and genetics limitations
Do not convert blackish appearance into a declared breeding genetic inheritance or documented first breeder.
Original references
Links are research leads; they do not certify every statement. Check original taxonomy and date.
Public Discord research discussion
Follow the original forum topic. It is a discussion record, not independent scientific verification.