Biology:Freshwater butterflyfish
| Freshwater butterflyfish | |
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Scientific classification 
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| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Osteoglossiformes |
| Family: | Pantodontidae |
| Genus: | Pantodon W. K. H. Peters, 1877 |
| Species: | P. buchholzi
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| Binomial name | |
| Pantodon buchholzi W. K. H. Peters, 1877
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The freshwater butterflyfish or African butterflyfish (Pantodon buchholzi) is a species of osteoglossiform fish native to freshwater habitats in the Niger and Congo basins of western and central Africa. It is the only extant species in the family Pantodontidae. It is not closely related to saltwater butterflyfishes.
Evolution
The freshwater butterflyfish is the last surviving member of a family that was diverse during the Late Cretaceous period, with many pantodontid genera known from the Cenomanian-aged Sannine Formation of Lebanon. These early pantodontids inhabited a marine environment off the coast of northern Africa and are the earliest known marine osteoglossomorphs, suggesting that the ancestors of Pantodon colonized freshwater habitats independently of other osteoglossiforms. These Cretaceous marine pantodontids appear to vary in their relation to the extant genus; of them, the closest relative and sister genus to Pantodon appears to be Palaeopantodon.[2][3]
Populations of freshwater butterflyfish in the Niger vs. the Congo basins appear virtually identical in morphology, but mtDNA divergence estimates suggest an extreme level of genetic divergence between them, dating to the Late Paleocene (57 million years ago) or earlier. This is one of the most dramatic cases of morphological stasis (in which two allopatric populations remain similar in appearance despite achieving a great level of genetic divergence from one another) known in a vertebrate taxon, and may suggest some level of cryptic speciation within the genus.[4]
Genetic studies suggest that the freshwater butterflyfish has experienced one of the greatest losses of whole Hox gene clusters in a teleost fish, with only 5 Hox clusters present after a presumed loss of 3 Hox clusters in the past. Despite this, it retains a similar overall number of Hox genes to other teleosts, due to a high proportion of duplicated genes in certain clusters. Due to its small size, widespread availability in captivity, and relatively small genome, the freshwater butterflyfish may serve as an attractive model organism, despite being studied less compared to other model fish taxa, which are clupeocephalans.[5]
Description and habits
Freshwater butterfly fish are small, no more than 13 cm (5.1 in) in length, with very large pectoral fins. It has a large and well-vascularized swim bladder, enabling it to breathe air at the surface of the water. It is carnivorous, feeding primarily on aquatic insects and smaller fishes.[6]
The freshwater butterflyfish is a specialized surface hunter. Its eyes are constantly trained to the surface and its upturned mouth is specifically adapted to capture small prey along the water's surface. If enough speed is built up in the water, a butterflyfish can jump and glide a small distance above the surface to avoid predation. It also wiggles its pectoral fins as it glides, with the help of specialized, enlarged pectoral muscles, the ability which earned the fish its common name.[7]
When freshwater butterflyfish spawn, they produce a mass of large floating eggs at the surface. Fertilisation is believed to be internal. Eggs hatch in about seven days.
Distribution
Freshwater butterflyfish are found in the slightly acidic, standing bodies of water in West Africa. They require a year-round temperature of 73–86 °F (23–30 °C). They are found in slow- to no-current areas with high amounts of surface foliage for cover. They are commonly seen in Lake Chad, the Congo Basin, throughout lower Niger, Cameroon, Ogooue, and upper Zambezi. They have also been seen in the Niger Delta, lower Ogooue, and in the lower Cross River.
In the aquarium
See also
- Flying and gliding animals
- List of freshwater aquarium fish species
References
- ↑ Lalèyè, P.; Moelants, T. (2020). "Pantodon buchholzi". IUCN Red List of Threatened Species 2020. doi:10.2305/IUCN.UK.2020-2.RLTS.T183157A135016934.en. https://www.iucnredlist.org/species/183157/135016934. Retrieved 18 May 2025.
- ↑ Taverne, L. (2021). "The Pantodontidae (Teleostei, Osteoglossomorpha) from the marine Cenomanian (Upper Cretaceous) of Lebanon. 3°. Palaeopantodon vandersypeni gen. and sp. nov.". Geo-Eco-Trop. 45 (4): 699–708. http://www.geoecotrop.be/uploads/publications/pub_454_14.pdf.
- ↑ Taverne, L.; Capasso, L. (2012). "Osteology and relationships of Prognathoglossum kalassyi gen. and sp. nov. (Teleostei, Osteoglossiformes, Pantodontidae) from the marine Cenomanian (Upper Cretaceous) of En Nammoura (Lebanon)". Cybium 36 (4): 563–574. https://www.vliz.be/imisdocs/publications/ocrd/303283.pdf.
- ↑ Lavoué, Sébastien; Miya, Masaki; Arnegard, Matthew E.; McIntyre, Peter B.; Mamonekene, Victor; Nishida, Mutsumi (2011-04-07). "Remarkable morphological stasis in an extant vertebrate despite tens of millions of years of divergence" (in en). Proceedings of the Royal Society B: Biological Sciences 278 (1708): 1003–1008. doi:10.1098/rspb.2010.1639. ISSN 0962-8452. PMID 20880884.
- ↑ Martin, Kyle J.; Holland, Peter W.H. (2014). "Enigmatic Orthology Relationships between Hox Clusters of the African Butterfly Fish and Other Teleosts Following Ancient Whole-Genome Duplication" (in en). Molecular Biology and Evolution 31 (10): 2592–2611. doi:10.1093/molbev/msu202. ISSN 1537-1719. PMID 24974377. PMC 4166920. https://academic.oup.com/mbe/article-lookup/doi/10.1093/molbev/msu202.
- ↑ Greenwood, P.H.; Wilson, M.V. (1998). Paxton, J.R.. ed. Encyclopedia of Fishes. San Diego: Academic Press. p. 81. ISBN 0-12-547665-5.
- ↑ Berra, Tim M. (2001). Freshwater Fish Distribution. San Diego: Academic Press. ISBN 0-12-093156-7.
Bibliography
- "Pantodon buchholzi". Integrated Taxonomic Information System. https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=161901. Retrieved 11 March 2006.
- Froese, Rainer and Pauly, Daniel, eds. (2005). "Pantodon buchholzi" in FishBase. November 2005 version.
- Innes, Dr William T., Exotic Aquarium Fishes, Innes Publishing Co. Philadelphia, 1935
Wikidata ☰ Q260106 entry
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