Superregnum: Eukaryota
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Cladus: Craniata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Cladus: Synapsida
Cladus: Eupelycosauria
Cladus: Sphenacodontia
Cladus: Sphenacodontoidea
Ordo: Therapsida
Cladus: Theriodontia
Subordo: Cynodontia
Cladus: Mammaliaformes
Classis: Mammalia
Subclassis: Trechnotheria
Infraclassis: Zatheria
Supercohort: Theria
Cohort: Eutheria
Cohort: Placentalia
Cladus: Boreoeutheria
Superordo: Laurasiatheria
Ordo: Artiodactyla
Subordo: Whippomorpha
Infraordo: Cetacea
Cladus: Neoceti
Parvordo: Odontoceti
Cladus: Delphinida
Superfamilia: Delphinoidea
Familia: Delphinidae
Genus: Sotalia
Species: Sotalia fluviatilis
Name
Sotalia fluviatilis (Gervais & Deville, 1853)
References
Sotalia fluviatilis in Mammal Species of the World.
Wilson, Don E. & Reeder, DeeAnn M. (Editors) 2005. Mammal Species of the World – A Taxonomic and Geographic Reference. Third edition. ISBN 0-8018-8221-4.
[1] Listed animal in CITES Appendix I
Vernacular names
English: Tucuxi, Estuarine-dolphin
suomi: Rannikkodelfiini
magyar: Parti delfin, folyami gadamu, tucuxi
日本語: コビトイルカ
polski: Delfin tucuxi, delfin amazoński
português: Tucuxi
svenska: Guyanadelfin
Türkçe: Haliç yunusu
The tucuxi (Sotalia fluviatilis), alternatively known in Peru bufeo gris or bufeo negro, is a species of freshwater dolphin found in the rivers of the Amazon basin. The word tucuxi is derived from the Tupi language word tuchuchi-ana, and has now been adopted as the species' common name. Despite being found in geographic locations similar to those of 'true' river dolphins such as the boto, the tucuxi is not closely related to them genetically. Instead, it is classed in the oceanic dolphin family (Delphinidae).
Physically, the species resembles the bottlenose dolphins, but differs sufficiently to be placed in a separate genus, Sotalia. The Guiana dolphin (Sotalia guianensis), a related dolphin present in coastal and estuarine environments and formerly grouped together with the tucuxi, have recently been recognized as a distinct species.
Description
The tucuxi is frequently described (see references below) as looking similar to the bottlenose dolphin, but it is typically smaller at around 1.5 m (4.9 ft). The dolphin is colored light to bluish grey on its back and sides. The ventral region is much lighter, often pinkish. It is theorized that this pinkish color may be caused or intensified by increased blood flow.[3] The dorsal fluke is typically slightly hooked. The beak is well-defined and of moderate length. There are 26 to 36 pairs of teeth in the upper and lower jaws.[4] The tucuxi has one of the largest known encephalization quotients among mammals.[5]
Taxonomy
The tucuxi (Sotalia fluviatilis) was described by Gervais and Deville in 1853, and the costero (Sotalia guianensis) by Pierre-Joseph van Bénéden in 1864. These two species were subsequently synonymized, with the two species being treated as subspecies of marine and freshwater varieties.[6] The first to reassert differences between these two species was a three-dimensional morphometric study of Monteiro-Filho and colleagues.[7] Subsequently, a molecular analysis by Cunha and colleagues[8] unambiguously demonstrated that Sotalia guianensis was genetically differentiated from Sotalia fluviatilis. This finding was reiterated by Caballero and colleagues[9] with a larger number of genes. The existence of two species has been generally accepted by the scientific community.
Distribution
The tucuxi exists along much of the length of the Amazon River and many of its tributaries, and is found in Venezuela, Brazil, Peru, Ecuador, southeastern Colombia. Numerous individuals have been seen in the Orinoco River further north, though it is not clear whether these are tucuxi or costero. This species occurs in freshwater habitats only.[10]
Food and foraging
Tucuxis forage in tight groups, often chasing fish in rapid dashes just below the water surface, with fish jumping out of their way. Thirty species of fish are known to be prey, some living in protected lakes and channels, while others occur in fast-flowing rivers.[10]
Behaviour
The tucuxi exists in small groups of about 10-15 individuals, and swim in tight-knit groups, suggesting a highly developed social structure. Tucuxis are quite active and may jump clear of the water (a behavior known as breaching), somersault, spy-hop or tail-splash. They are unlikely, however, to approach boats.
Tucuxis have been observed to feed with other river dolphins. They feed on a wide variety of fish. Studies of growth layers suggest the species can live up to 35 years . The oldest known animal was 36 years of age.[10]
Conservation
Tucuxi skeleton
The tucuxi is endemic to the regions described above; although no precise estimates of population are available, it is common. A significant human problem is fishing nets. Deliberate hunting in the Amazon basin for food has also been reported. Pollution, in particular, mercury poisoning of water due to gold mining, is a particular concern for this species. The IUCN also cites habitat fragmentation by dam construction as a threat, though more detailed study is necessary.[1]
Tucuxis are observed not to maintain good health and attitude in captive environments. A few tucuxis remained in captivity in European aquaria, but the last one ("Paco") died in 2009 in the Zoo of Münster, Germany.[11]
The tucuxi is listed on Appendix II[12] of the Convention on the Conservation of Migratory Species of Wild Animals (CMS). It is listed on Appendix II[12] as it has an unfavourable conservation status or would benefit significantly from international co-operation organised by tailored agreements.
See also
Cetaceans portal iconMammals portal Marine life portal
List of cetaceans
Environmental issues in Brazil
References
da Silva, V.; Martin, A.; Fettuccia, D.; Bivaqua, L.; Trujillo, F. (2020). "Sotalia fluviatilis". IUCN Red List of Threatened Species. 2020: e.T190871A50386457. doi:10.2305/IUCN.UK.2020-3.RLTS.T190871A50386457.en. Retrieved 19 November 2021.
"Appendices | CITES". cites.org. Retrieved 14 January 2022.
Edwards and Schnell, Holly and Gary (2001). "Body Length, Swimming Speed, Dive Duration, and Coloration of the Dolphin Sotalia fluviatilis (Tucuxi) in Nicaragua" (PDF). Caribbean Journal of Science. Retrieved 30 July 2015.
Monteiro-Neto, Cassiano; Alves-Júnior, Tarcísio Teixeira; Ávila, Francisco J. Capibaribe; Campos, Alberto Alves; Costa, Alexandra Fernandes; Silva, Cristine Pereira Negrão; Furtado-Neto, Manuel A. Andrade (2000). "Impact of fisheries on the tucuxi (Sotalia fluviatilis) and rough-toothed dolphin (Steno bredanensis) populations off Ceara state, northeastern Brazil" (PDF). Aquatic Mammals. European Association for Aquatic Mammals. 26 (1): 49–56. ISSN 1996-7292. OCLC 55134873. Retrieved January 2013. {{cite journal}}: Check date values in: |access-date= (help)
William F. Perrin; Bernd Würsig; J.G.M. Thewissen (2009). Encyclopedia of Marine Mammals. Academic Press. p. 150. ISBN 978-0-08-091993-5.
Borobia, M.; S. Siciliano; L. Lodi & W. Hoek (1991). "Distribution of the South American dolphin Sotalia fluviatilis". Canadian Journal of Zoology. 69 (4): 1024–1039. doi:10.1139/z91-148.
Monteiro-Filho, E. L. D. A.; L. Rabello-Monteiro & S. F. D. Reis (2008). "Skull shape and size divergence in dolphins of the genus Sotalia: A morphometric tridimensional analysis". Journal of Mammalogy. 83: 125–134. doi:10.1644/1545-1542(2002)083<0125:SSASDI>2.0.CO;2.
Cunha, H. A.; V. M. F. da Silva; J. Lailson-Brito Jr.; M. C. O. Santos; P. A. C. Flores; A. R. Martin; A. F. Azevedo; A. B. L. Fragoso; R. C. Zanelatto & A. M. Solé-Cava (2005). "Riverine and marine ecotypes of Sotalia dolphins are different species". Marine Biology. 148 (2): 449–457. doi:10.1007/s00227-005-0078-2.
Caballero, S.; F. Trujillo; J. A. Vianna; H. Barrios-Garrido; M. G. Montiel; S. Beltrán-Pedreros; M. Marmontel; M. C. Santos; M. R. Rossi-Santos; F. R. Santos & C. S. Baker (2007). "Taxonomic status of the genus Sotalia: species level ranking for "tucuxi" (Sotalia fluviatilis) and "costero" (Sotalia guianensis) dolphins". Marine Mammal Science. 23 (2): 358–386. doi:10.1111/j.1748-7692.2007.00110.x.
A. Berta, ed. (2015). Whales, Dolphins, and Porpoises: A Natural History and Species Guide. University of Chicago Press.
Blogger, Guest. "A HISTORY OF CAPTIVE RARITIES AND ODDITIES (PART 2)". Ric O'Barry Dolphin Project. Retrieved 9 October 2020.
"Appendix II Archived 11 June 2011 at the Wayback Machine" of the Convention on the Conservation of Migratory Species of Wild Animals (CMS). As amended by the Conference of the Parties in 1985, 1988, 1991, 1994, 1997, 1999, 2002, 2005 and 2008. Effective: 5 March 2009. Convention on Migratory Species page on the Tucuxi
National Audubon Society Guide to Marine Mammals of the World ISBN 0-375-41141-0
Encyclopedia of Marine Mammals ISBN 0-12-551340-2
Whales, Dolphins and Porpoises, Mark Carwardine, ISBN 0-7513-2781-6
Retrieved from "http://en.wikipedia.org/"
All text is available under the terms of the GNU Free Documentation License
