Corresponding author: Chiara C. F. Lubich ( lubichchiara@gmail.com ) Academic editor: Eva Decru
© 2021 Chiara C. F. Lubich, André R. Martins, Carlos E. C. Freitas, Lawrence E. Hurd, Flávia K. Siqueira-Souza.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Lubich CCF, Martins AR, Freitas CEC, Hurd LE, Siqueira-Souza FK (2021) A candiru, Paracanthopoma sp. (Siluriformes: Trichomycteridae), associated with a thorny catfish, Doras phlyzakion (Siluriformes: Doradidae), in a tributary of the middle Rio Negro, Brazilian Amazon. Acta Ichthyologica et Piscatoria 51(3): 241-244. https://doi.org/10.3897/aiep.51.64324
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Amazonian vampire catfish, known regionally as “candiru”, are recognized as hematophagous fishes, but information on their ecology remains limited. We provide the first report of Paracanthopoma sp. (Vandelliinae) found attached to the body surface of a thorny catfish, Doras phlyzakion Sabaj Pérez et Birindelli, 2008, bellow the lateral bony plates, rather than at the gills where they have usually been found. The specimens had not recently ingested blood or other identifiable fish remains (flesh, skin, or mucus), which could be an indication they have been using this host for protection or as a phoretic association, rather than for feeding. Thus, the interaction of vampire fish with the host catfish may be more complex than previously understood.
candiru, vampire fish, interspecific fish relations, Actinopterygii, Siluriformes, Vandelliinae
Although predation has often been considered the main interspecific relation structuring ecological communities (
Candiru is the common name of Vandelliinae catfishes (Trichomycteridae) that are known to be parasites of other fish (
Some species of parasitic catfishes, such as those of the genus Paracanthopoma (Vandelliinae), seem to exhibit behavior of long-lasting attachment to their host fish, which may relieve them of the time and energy required to search for prey (
The catch sample we examined was part of a study on the fish assemblages done on 7 April 2019, at a lake of the Demeni River basin (0°23′36.2′′S, 62°51′43.4′′W), a left-bank tributary of the Negro River (Fig.
A regression was performed to evaluate the host length vs. the number of parasites. The regression was performed using the software R version 4.0.2 (
Twelve specimens of the vampire catfish, Paracanthopoma sp. (Trichomycteridae, Vandelliinae), measuring 10.1–18.0 mm SL (15.7 ± 2.5 mm) were found attached to the body of nine adult specimens of Doras phlyzakion weighing 30–106 g (69.11 ± 25.40 g) and measuring 110–160 mm (141.9 ± 17.6 cm). Each specimen of D. phlyzakion hosted one or two specimens of Paracanthopoma sp. attached to the outside of the body near the lateral bone plates (Fig.
Paracanthopoma is a monophyletic genus of vampire catfish (
Previously it has been reported that Vandelliinae species attach to the gills of their hosts for feeding (
The absence of blood or other food remains in the stomach of the Paracanthopoma specimens apparently weakens the hypothesis of a parasitic relation with D. phlyzakion. However, such kind of relation cannot be discarded, since empty stomachs are a common fact among carnivorous fish and may reflect a momentaneous condition related to the time of collection of the candiru catfishes, as well as to a fast digestion rate of the ingested food. Despite this uncertainty, our finding of several Paracanthopoma individuals attached to the 9 collected individuals of D. phlyzakion suggests the existence of some strong interspecific association. For instance, the association could provide some form of protection from predators to the candiru catfish (
In addition to feeding and protection, riding on the host can greatly extend the movement capabilities of small candirus.
In conclusion, the observed interspecific association may combine elements of parasitism, protection from predators and a phoretic association between Paracanthopoma sp. and D. phlyzakion.
We are grateful to the PROPESCA / Rio Negro project for providing financial and logistical support. H. D. Beltrão for identifying vampire fish; J. A. S. Zuanon for identifying the host species Doras phlyzakion.