The Prochilodontidae, commonly known as the bocachicos or flannel-mouthed characins, are a small family of freshwater fishes found primarily in the northern half of South America, south to Paraguay and northern Argentina. This family is closely related to the Curimatidae, and were included in Characidae before that family was revised and split.
These fish have fleshy lips bearing rows of small teeth; their lips are able to be extended into a sucking disc used to feed on detritus and aufwuchs. They often live in huge schools, traveling upriver to spawn. In their native range, they are a popular food fish, and are caught in large numbers.
Taxonomy Prochilodontidae possess a number of distinguishing features, such as their oral disc, procumbent dorsal fin spines, along with specific features of the front half of their skeleton, being those of the skull, hyoid and pharyngeal apparati, and branchial arch.
Prochilodontidae contains the following genera: Ichthyoelephas Posada, 1909 Prochilodus Agassiz, 1829 Semaprochilodus Fowler, 1941
Cladogram of the most parsimonious hypothesis of relationships based on morphological analysis by Castro and Vari (2008):
Biology
After metamorphosis from their larval stage, they develop their oral disc, a feature unique to their family. The oral disc are made up of expanded fleshy lips which bears all their teeth, which are not rooted to the jaws as in other characins. The associated structures of the skull, gill arches, and suspensorium also underwent adaptation to support this feeding apparatus. Along with adaptations of the digestive system (notably the "elaboration and elongation" of the pyloric caeca and intestines),Angelescu, V., and F.S. Gneri 1949. Adaptaciones del aparato digestivo al regimen alimenticio em algunos peces del Rio Uruguay y del Rio de la Plata, I: Tipo omnivoro and iliofago en representantes de las familias "Loricariidae" y "Anostomidae." Revista de la Instituto Nacional de Ciencias Naturales Buenos A ires, 1 (6): 162-27Menin, E., and O.M. Mimura 1991. Aspectos anatomicos dos orgaos epibranquiais de Prochilodus marggravii (Walbaum, 1792) e Prochilodus affinis Reinhardt, 1874 (Characiformes, Prochilodontidae). Revista Ceres. 38(217):229-239. these features allow prochilodontids to feed on detritus and aufwuchs, food sources typically exploited by invertebrates in a freshwater ecosystem. Feeding directly on the detritus and aufwuchs may have allowed prochilodontids and curimatids, which are sister groups, to become major if not dominant components of Neotropical freshwater ichthyofauna.Bowen, S.H. 1984. Detritivory in Neotropical Fish Communities. In T.M. Zaret, Evolutionary Ecology of Neotropical Fresh Water Fishes, pages 59-66. The Hague: W. Junk Publishers. Their feeding action reduces the amount of built-up sediment which affects the composition of invertebrate fauna in a waterway; this renders them as keystone species by their role as ecosystem engineers.Flecker, A.S. 1996. Ecosystem Engineering by a Dominant Detritivore in a Diverse Tropical Stream. Ecology, 77(6): 1845-1854.
They can make audible grunting noises that have been described as resembling the sound of a motorbike.
Prochilodontids undergo regular migration, thought to be related to foraging and reproduction: daily migrations in the Paraná River may reach distances of , longer migrations may stretch for at least ,Sverlij, S., A. Ros, and G Orti 1993. Sinopsis de los datos biologicos y pesqueros del Sabalo Prochilodus lineatus (Valenciennes, 1847). FAO Sinopsis sobre la Pesca, 154: 1-64. and they may leap for several meters to overcome obstacles,Goulding, M. 1981. Man and Fisheries on an Amazon Frontier. 137 pages. The Hague: Junk Publishers.Godoy, M.P. de 1975. Peixes do Brazil: Sub-ordem Characoidei; Bacia do Rio Mogi-Guassu. 846 pages. Piracicaba, Brazil: Editora Franciscana.Mochek, A.D., and D.S. Pavlov 1998. The Ecology of Sabalo Prochilodus lineatus (Curimatidae, Characoidei) of the Pilcomayo River (South America). Journal of Ichthyology, 38(1 ):28—36. [Originally published in Russian in Voprosy lkhtiologii. 38(1):33-41.] These journeys allow for significant levels of gene flow (reflected in high levels of genetic homogeneity within species of prochilodontids, despite inhabiting disparate river basins)Revaldaves, E., E. Renesto, and M.F.P.S. Machado 1997. Genetic Variability of Prochilodus lineatus (Characiforms, Prochilodontidae) in the Upper Parana River. Brazilian Journal ofGenetics, 20(3):381-388.Sivasundar, A., Bermingham, E., and G Orti 2001. Population Structure and Biogeography of Migratory Freshwater Fishes (Prochilodus: Characiformes) in Major South American Rivers. Molecular Ecology. 10(2):407-417. along with the transport of nutrients and energy when they are hunted down by less migratory predators.Winemiller, K.O., and D.B. Jepsen 1998. Effects of Seasonality and Fish Movement on Tropical River Food Webs. Journal of Fish Biology, 53 (supplement A):267-296.Lucas, M.C, and E. Baras 2001. Migration of Freshwater Fishes. 420 pages. Oxford: Blackwcll Science Ltd.
Biogeographical evidence suggests that Prochilodus may have retained its bauplan for at least 8 million years and possibly longer: Prochilodus magdalenae inhabits waterways which were separated from other river basins by the northern portions of the Andean Cordilleras by the late Miocene, around 11.8 to 10.0 million years ago.Lundberg, J.G, L.G Marshall, J. Guerrero, B. Horton, M.C.S.L. Malabarba, and F. Wesselingh 1998. The Stage for Neotropical Fish Diversification: A History of Tropical South American Rivers. In L. Malabarba, R. Reis, R.P. Vari, C. Lucena, and M. Lucena, editors, Phytogeny and Classification of Neotropical Fishes, pages 13-48. Porto Alegre, Brazil: Edipucrs. Additionally, Prochilodontidae may have evolved much earlier than that: fossils of the derived curimatid Cyphocharax mosesi were dated to the Oligocene, at least 22.5 million years ago, which suggests the majority of Curimatidae's genera had by then evolved. As its sister group, Prochilodontidae is thought to have emerged by that time too. Thus, it is thought that Prochilodus and the common ancestor of Semaprochilodus and Ichthyoelephas were extant by at least the Miocene; other fish genera, such as the pacu Colossoma and the catfish Phractocephalus, possess fossil evidence suggesting they too were extant by that epoch.Lundberg, J.G, A. Machado-Allison, and R.F. Kay 1986. Miocene Characid Fishes from Colombia: Evidence for Evolutionary Statis and Extirpation in the South American Ichthyofauna. Science. 234:208-209.
Relation to humans
Their abundance is reflected by their prominence in South American freshwater fisheries:Araujo-Lima, C.A.R.M.; and M.L. Ruffino (2003). Migratory Fishes of the Brazilian Amazon. Pp. 233—302 in: Carolsfeld, J.; B. Harvey; C. Ross; and A. Baer (editors). Migratory Fishes of South America. single species of prochilodontids often make up more than 50% of the total catch of fish in a river basin,Bonetto, A.A.1975. Hydrologic Regime of the Parana River and Its Influence on Ecosystems. In A.D. Hasler, editor, Coupling of Land and Water Systems. Ecological Studies, 10:175-197. New York: Springer-Verlag. and may sometimes reach 95% of the fishery in some regions.Sverlij, S., A. Ros, and G Orti 1993. Sinopsis de los datos biologicos y pesqueros del Sabalo Prochilodus lineatus (Valenciennes, 1847). FAO Sinopsis sobre la Pesca, 154: 1-64. Prochilodontid species are important components in fisheries from Venezuela to Argentina.Espinosa, V. de, and C.B. Gimenez 1974. Estudio sobre la biologia y pesca del bocochico Prochilodus reticulatus (Valenciennes) en el Lago de Maracaibo. lnforme Tecnico, Oficina Nacional de Pesca (Caracas), 63:1-32.Novoa, R., D., F. Cervigon, and F. Ramos 1982. Catalogo de los recursos pesqueros del Delta del Orinoco. In D. Novoa R., Los recursos pesqueros del Rio Orinoco y su explotacion, pages 263-386. Caracas: Editoria ArteBonetto, A.A. 1994. Austral Rivers of South America. In R. Margalef, editor, Limnology Now: A Paradigm of Planetary Problems, pages 425—472. Amsterdam: Elsevier Science B.V. Their value as food may have led to their introduction in Papua New Guinea.Wafy, A. 2001. The Different Fish Species in Sepik River. Focus Viewpoint, pages 1, 2. Port Moresby, Papua New Guinea: Post Courier.
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