Helogenes gouldingi Vari & Ortega, 1986
Identification: The possession of 15 principal caudal-fin rays, with eight principal rays in the lower lobe of the fin, distinguishes Helogenes gouldingi from both H. uruyensis and H. marmoratus, which have 16 principal caudal-fin rays, with nine principal rays in the lower lobe of the fin. The 39-43 anal-fin rays of H. gouldingi further separate it from H. uruyensis, which has 32-37 rays. Helogenes gouldingi and H. castaneus are separable in the number of anal-fin rays (39-43, vs. 43-49), relative snout lengths, and relative distance between the rayed and adipose dorsal fins. Differences in the relative distances from the snout to the anal fin, and the relatives lengths of the base of the anal fin, and medial mandibular barbel further distinguish H. gouldingi from H. uruyensis.
Range: Helogenes gouldingi is known from the Madeira River basin, Brazil.
Information from Vari, R. P. & H. Ortega. 1986. The catfishes of the Neotropical family Helogenidae (Ostariophysi: Siluroidei). Smithsonian Contributions to Zoology, 442: 1-20.