The dwarf cichlid known in the aquarium hobby as Apistogramma sp. ‘black chin’, ‘Schwarzkinn’, or ‘Pucallpa’ for almost 20 years has been officially described as A. allpahuayo in a paper published in the journal ‘Vertebrate Zoology’.
It appears to be a member of the A. cacatuoides species group within the larger A. cacatuoides lineage and can be separated from all other members of the genus by a combination of characters as follows; adult males with black w-shape marking on lower jaw; caudal-fin lyrate; large jaws with lips hypertrophied and yellow to orange; 7 vertical bars on body, restricted to upper half of body in males; a dark, roundish spot on the caudal peduncle, clearly separated from the lateral body stripe which ends at vertical body bar 7; dorsal-fin serrated with conspicuous extensions to the anterior membranes; one of dorsal-fin spines 3-5 longest, a feature unique within the genus.
The specific name is in reference to the type locality which is located within the Reserva Nacional Allpahuayo-Mishana, a large national reserve located within the rainforest south of Iquitos in the Loreto region of northern Peru. A. allpahuayo is apparently restricted to minor, mostly black water, tributaries and small rivers within the reserve and west of the road between Iquitos and Nauta and therefore appears endemic to the Río Nanay watershed.
A further interesting point about the new species is that it’s the only Apistogramma in which functional sex change has been recorded, an adult female specimen which had reproduced on several occasions in the aquarium developing full male size, colour pattern, and morphological features following the death of its male partner. A single fry from a previous spawn was allowed to grow alongside this fish and turned out to be female, and on reaching sexual maturity successfully spawned with its former mother.
The protogynous individual was preserved following a second spawning event and its gonads fixed for further investigation, the results of which will be published separately.
For further information please refer to the full, open access paper: Römer, U, J. Beninde, F. Duponchelle, A. Vela Díaz, H. Ortega, I. Hahn, D. P. Soares, C. Díaz Cachay, C. R. García Dávila, S. S. Cornejo and J.-F. Renno. 2012. Description of Apistogramma allpahuayo sp. n., a new dwarf cichlid species (Teleostei: Perciformes: Geophaginae) from in and around the Reserva Nacional Allpahuayo Mishana, Loreto, Peru. Vertebrate Zoology 62(2): 189-212