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Bolivianischer Amazonasdelfin ( германски )

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Der Bolivianische Amazonasdelfin (Inia boliviensis, Syn.: Inia geoffrensis boliviensis) ist eine im Oberlauf des Rio Madeira in Bolivien und im Südwesten Brasiliens vorkommende Art der Amazonas-Flussdelfine. Der ehemals als Unterart des Amazonasdelfins (Inia geoffrensis) betrachtete Delfin wurde im Jahr 2008 durch molekularbiologische Untersuchungen als eigenständige Art bestätigt.

Merkmale

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Schädel und Unterkiefer des Bolivianischen Amazonasdelfins

Der Bolivianische Amazonasdelfin entspricht in seinem Aussehen und in seiner Körpergröße dem Amazonasdelfin (Inia geoffrensis), als dessen Unterart er lange betrachtet wurde, und dem Araguaia-Delfin (Inia araguaiaensis). Vermessungen der Tiere sind selten und es gibt nur zwei offizielle Angaben von Körperlängen zweier Weibchen, die 208 und 216 Zentimeter lang waren. Innerhalb der Gattung kommt ein Sexualdimorphismus vor, die Männchen sind in der Regel größer und kräftiger gebaut; dies wird entsprechend auch beim Bolivianischen Amazonasdelfin angenommen. Der Schädel des Bolivianischen Amazonasdelfins enthält pro Unterkieferhälfte 31 bis 34 Zähne und damit mehr als der der beiden anderen Arten (24–28 bei Inia araguaiaensis und 25–29 bei I. geoffrensis), der Oberkiefer enthält 31 bis 35 Zähne. 9 bis 11 der Zähne im Ober- und Unterkiefer sind molar-ähnlich. Der Schädel ist zudem schmaler gebaut, das Rostrum ist mit einer Länge von etwa 73 % der Gesamtlänge des Schädels länger als beim I. geoffrensis, wo sie etwa 65 % der Gesamtlänge des Schädels beträgt.[1]

Verbreitung

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Verbreitungsgebiete der Amazonas-Flussdelfine (Iniidae); Hellgrün dargestellt ist das Verbreitungsgebiet des Amazonasdelfins, blau das von Inia araguaiaensis und violett das von Inia boliviensis

Der Bolivianische Amazonasdelfin ist nur im Oberlauf des Rio Madeira und verbundener Flusssysteme im nördlichen Bolivien und im Südwesten Brasiliens vor. Das Verbreitungsgebiet liegt im bolivianischen Flachland nördlich der Chiquitanía. Neben dem Rio Madeira gehören auch der Río Beni, der Río Ichilo, der Río Mamoré, der Río Ipurupuru, der Río Ibare, der Río Baré, der Río Abuná und der Río Iténez zum Verbreitungsgebiet der Tiere.[1]

Lebensweise

Der Bolivianische Amazonasdelfin lebt in sedimentreichen Flüssen, Seen und Überflutungsbereichen des Flachlands, wobei er vor allem Bereich mit klaren Wasser bevorzugt. Wie die anderen Arten der Gattung sammeln sich die Tiere vor allem an Zusammenflüssen, sind jedoch prinzipiell in allen verfügbaren Habitaten präsent.

Über die Lebensweise der Art liegen nur sehr begrenzte bis gar keine Informationen vor, sie entspricht jedoch wahrscheinlich im Wesentlichen der des Amazonasdelfins. Wie dieser ernährt sich auch der Bolivianische Amazonasdelfin primär von Fischen. Die Paarungszeit und Geburten finden wahrscheinlich im gesamten Jahr statt, wobei Jungtiere vor allem in Flachwasserzeiten vermehrt geboren werden.[1]

Systematik

Der Bolivianische Amazonasdelfin wurde im Jahr 1834 von dem französischen Naturforscher Alcide Dessalines d’Orbigny aus dem Río Iténez in Bolivien erstmals beschrieben. 2008 wurde er mit Hilfe molekularbiologischer Methoden als eigenständige Art bestätigt.[2]

Gemeinsam mit dem Amazonasdelfins (Inia geoffrensis) und dem erst 2014 beschriebenen Araguaia-Delfin (Inia araguaiaensis) bildet er die Gattung Inia, die einzige Gattung der Amazonas-Flussdelfine (Iniidae). Innerhalb dieser ist der Araguaia-Delfin die Schwesterart des Amazonasdelfins und hat sich von diesem während des Gelasium vor etwa 2 Millionen Jahren getrennt, als das Stromgebiet von Rio Araguaia und Rio Tocantins vom Amazonasbecken abgeschnitten wurde. Die Schwestergruppe dieser Klade ist der Bolivianische Amazonasdelfin. Er wurde vor etwa 2,9 Millionen Jahren durch die Teotonio-Stromschnellen im oberen Rio-Madeira-Gebiet isoliert.[3]

Gefährdung und Schutz

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Bolivianischer Amazonasdelfin im natürlichen Lebensraum

Wie bei den anderen Arten der Flussdelfine liegen auch für den Bolivianischen Amazonasdelfin nur sehr wenige Daten zu den Populationen und Beständen vor. Von der International Union for Conservation of Nature and Natural Resources (IUCN) wird die Art bislang nicht als eigenständig, sondern als Unterart des Amazonasdelfins betrachtet und aufgrund der Datenlage als „data deficient“ eingeordnet.[4] Schätzungen gehen von einem Gesamtbestand von etwa 1400 bis 4000 Individuen und einer Dichte von 3,2 bis 3,5 Individuen pro Flusskilometer im Verbreitungsgebiet aus.[1]

Obwohl die Populationen des Bolivianischen Amazonasdelfins von denen des Amazonasdelfins durch Stromschnellen und andere Barrieren getrennt sind, kam es vor allem bei Hochwasser regelmäßig dazu, dass einzelne Tiere die Barrieren überwanden. Durch den Bau der Jirau-Talsperre und der Santo-Antônio-Talsperre am Rio Madeira von 2008 bis 2013 sind die Lebensräume nun vollständig getrennt.[1] In Bolivien ist die Art indirekt in der Political Constitution des Supreme Decree 25458 aus dem Juli 1999 geschützt, wonach die Jagd und der Handel mit Arten der nationalen Fauna verboten sind, bei denen eine Gefährdung angenommen wird. 2008 wurde im Departamento Beni ein Gesetz beschlossen, das den Bolivianischen Amazonasdelfin zum Naturerbe erklärt.[1]

Belege

  1. a b c d e f V.M.F. da Silva, A.R. Martin: Family Iniidae (Amazon River Dolphins); Bolivian Boto Inia boliviensis In: Don E. Wilson, Russell A. Mittermeier: Handbook of the Mammals of the World. 4. Sea Mammals. Lynx Edicions, Barcelona 2014; S. 378. ISBN 978-84-96553-93-4.
  2. M. Ruiz-García, S. Caballero, M. Martinez-Agüero, J.M. Shostell JM: Molecular differentiation among Inia geoffrensis and Inia boliviensis (Iniidae, Cetacea) by means of nuclear intron sequences. In: V.T. Koven (Herausgeber): Population Genetics Research Progress. Boca Raton, Nova Publishers 2008; S. 177–203.
  3. Tomas Hrbek, Vera Maria Ferreira Da Silva, Nicole Dutra, Waleska Gravena, Anthony R. Martin, Izeni Pires Farias: A New Species of River Dolphin from Brazil or: How Little Do We Know Our Biodiversity. In Samuel T. Turvey, PLoS ONE 9, 2014: e83623. doi:10.1371/journal.pone.0083623.
  4. Inia geoffrensis in der Roten Liste gefährdeter Arten der IUCN 2015.4. Eingestellt von: A.V. Linzey, NatureServe (G. Hammerson), 2008. Abgerufen am 3. Juli 2016.

Literatur

  • V.M.F. da Silva, A.R. Martin: Family Iniidae (Amazon River Dolphins); Bolivian Boto Inia boliviensis In: Don E. Wilson, Russell A. Mittermeier: Handbook of the Mammals of the World. 4. Sea Mammals. Lynx Edicions, Barcelona 2014; S. 378. ISBN 978-84-96553-93-4.
  • M. Ruiz-García, S. Caballero, M. Martinez-Agüero, J.M. Shostell JM: Molecular differentiation among Inia geoffrensis and Inia boliviensis (Iniidae, Cetacea) by means of nuclear intron sequences. In: V.T. Koven (Herausgeber): Population Genetics Research Progress. Boca Raton, Nova Publishers 2008; S. 177–203.

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Bolivianischer Amazonasdelfin: Brief Summary ( германски )

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Der Bolivianische Amazonasdelfin (Inia boliviensis, Syn.: Inia geoffrensis boliviensis) ist eine im Oberlauf des Rio Madeira in Bolivien und im Südwesten Brasiliens vorkommende Art der Amazonas-Flussdelfine. Der ehemals als Unterart des Amazonasdelfins (Inia geoffrensis) betrachtete Delfin wurde im Jahr 2008 durch molekularbiologische Untersuchungen als eigenständige Art bestätigt.

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Bolivian river dolphin ( англиски )

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The Bolivian river dolphin (Inia boliviensis) is a species of the genus Inia.

Taxonomy

Bolivian river dolphins were discovered by the Western world in 1832 by French researcher Alcide d'Orbigny.[2] The Bolivian river dolphin was briefly thought to be a subspecies (as I. geoffrensis boliviensis) of the Amazonian river dolphin, Inia geoffrensis, but differences in body structure and the isolation of the Bolivian river dolphin led to it being classified as its own species in 2012.[3] In a study conducted in 2015, it was also noted that any gene flow between I. geoffrensis (downstream) and I. boliviensis (upstream) would be a one way path flowing from upstream to downstream due to the Teotônio waterfall between them.[4] Despite any gene flow, these populations would also remain morphologically different from each other due to the differences in the environment in which they reside. Differences in seasonal water depth and speed would result in morphologically different species. In terms of research that has been conducted or could be conducted, the population size for these freshwater dolphins is incredibly small, making large sample sizes for scientific studies hard to work with.[5]

Species designation

Although older publications and some recent publications[6] consider the I. g. boliviensis population as distinct species from Inia geoffrensis, much of the scientific community, including the IUCN,[7] consider them to be a subspecies of Inia geoffrensis. Current classification,[8] therefore, considers them a single species, Inia geoffrensis, in the genus Inia, with two recognized subspecies. As of 2016, the Committee on Taxonomy of the Society for Marine Mammalogy[9] supports the designation of two subspecies. A recent study, with more comprehensive sampling of the Madeira system, including above and below the Teotonio Rapids (which were thought to obstruct gene flow), found that the Inia above the rapids did not possess unique mtDNA.[10] As such the species level distinction once held was not supported by further sampling. Therefore, the Bolivian river dolphin is currently recognized as a subspecies.

In September 2012, Bolivian President Evo Morales enacted a law to protect the dolphin and declared it a national treasure.[11]

Drawings of the Bolivian river dolphin by d'Orbigny 1847

French naturalist and palaeontologist Alcide Dessalines d'Orbigny explored South America from 1826 to 1833, including a stay in Bolivia from 1831 to 1833. He returned to France in 1834 and started to describe his scientific explorations, including the new Bolivian cetacean species "Inia boliviensis". In 1847, he and Paul Gervais compared it to "Delphinius geoffrensis" (=Amazon river dolphin, Inia geoffrensis), which had been described from a stuffed specimen in Lisbon, and the two were considered synonyms for more than a century. In 1973, however, a fresh study concluded that the specimens from Bolivia had more teeth than the specimens from elsewhere and that the rapids and water falls of the Madeira River acted as a barrier, effectively isolating the Bolivian population. The Bolivian river dolphin was therefore made a subspecies, Inia geoffrensis boliviensis. Morphological studies later in the 1970s added to the differences between the populations and the specific status Inia boliviensis was restored. There is, however, still no consensus on the taxonomic status of the Bolivian population (or that of the Orinoco River population, "I. g. humboldtiana").[12]

Description

The Bolivian river dolphin, or Inia boliviensis, is one of four freshwater river dolphin species in South America. Locally known as bufeos, it is found in some rivers in the Upper Madeira Basin of the Bolivian Amazon.[3] The Bolivian river dolphins are separated from the Amazonian River Dolphins by a series of rapids and falls.[13] The pink river dolphin is the largest freshwater dolphin in the world. It can reach up to 2.8 meters long and weigh as much as 180 kg. Compared to its cousin, the Amazonian river dolphin (Inia geoffrensis), the Bolivian river dolphin has more teeth, a smaller skull, and a longer body.[2]

Necropsies have shown the Bolivian river dolphin diet includes a variety of different species of fish, as well as crabs. In the necropsy of a juvenile dolphin, multiple different species of fish from at least 4 different families were found in its stomach contents. It is also worth noting that none of the species present in this particular juvenile's stomach were target species for fisheries.[13]

The dolphins are difficult to observe in the murky river water. However, in April 2022, three ecologists published photographs of Bolivian river dolphins play with a large (presumably dead) Beni Anaconda snake.[14][15]

Threats

The Inia boliviensis is bigger than its Amazon counterpart, the Inia geoffrensis

The Amazon river dolphin, Inia geoffrensis, is classified as endangered by the IUCN Red List. The Bolivian river dolphin faces a multitude of threats. Overfishing, deforestation, and hydroelectric construction are all major factors in the current population decline.[3] Fisheries also pose a threat to the dolphins, for fishermen might see the dolphins as competition for fish. Deceased dolphins have been noted to have wounds from nets, as well as cuts and mutilation most likely caused by humans.[3] River dolphins are some of the most at-risk marine animals worldwide due to their limited habitats and threats from land.

Conservation

Since the construction of the 2 hydroelectric dams in the segment of river where Bolivian river dolphins are found in 2008, the movement of the river has been blocked into 2 reservoirs of about 300 and 350 km2. Each dam is equipped with mechanisms to promote fish transportation between the reservoirs to prevent the populations from being evolutionarily cut off, however, it is unlikely the Bolivian river dolphins will use these transports. The upstream and downstream populations of I. boliviensis have been cut off by the design of the transport, as they can sustain only short bursts of swimming through high velocity water, and the transports are shallow and narrow with high velocity water, providing an effective barrier between populations. The dams can also cause a change to the fish community structure, and therefore altering the diet of Bolivian river dolphins.[16]

Conservation efforts to prevent further population decline of freshwater dolphins can begin with protecting areas from human influence. Limiting or removing boat traffic, creating better marine animal passageways through dams, and working with fisheries to live alongside wildlife instead of fighting against it are all important steps. Preserving habitats is important for species richness, genetic diversity, and ecosystem complexity.[16]

Behavior

Bolivian river dolphins are elusive and difficult to observe, as they typically swim below the surface.[17]

In August 2021, a research team observed two sexually aroused juvenile male dolphins near the Tijamuchi River playing with a Beni anaconda (Eunectes beniensis).[18]

See also

References

  1. ^ "Appendices | CITES". cites.org. Retrieved 2022-01-14.
  2. ^ a b “River Dolphins in South America.” BoliviaBella. Web. 15 February 2018.
  3. ^ a b c d Guizada, Luis and Enzo Aliaga-Rossel. "Abundance of the Bolivian River Dolphin (Inia Boliviensis) in Mamore River, Upper Madeira Basin." Aquatic Mammals, vol. 42, no. 3, July 2016, pp. 330-338.
  4. ^ Gravena, Waleska, et al. "Living between Rapids: Genetic Structure and Hybridization in Botos ( Cetacea: Iniidae: Inia Spp.) of the Madeira River, Brazil." Biological Journal of the Linnean Society, vol. 114, no. 4, Apr. 2015, pp. 764-777.
  5. ^ Ruiz-Garcia, Manuel, Eulalia Banguera, and Heiber Cardenas. "Morphological Analysis of Three Inia (Cetacea : Iniidae) Populations from Colombia and Bolivia." Acta Theriologica 51.4 (2006): 411-26. Web.
  6. ^ Martínez-Agüero, M.; S. Flores-Ramírez & M. Ruiz-García (2006). "First report of major histocompatibility complex class II loci from the Amazon pink river dolphin (genus Inia)" (PDF). Genetics and Molecular Research. 5 (3): 421–431. PMID 17117356. Archived from the original (PDF) on 2011-09-26. Retrieved 2009-05-27.
  7. ^ R.R. Reeves; T.A. Jefferson; L. Karczmarski; K. Laidre; G. O'Corry-Crowe; L. Rojas-Bracho; E.R. Secchi; E. Slooten; B.D. Smith; J.Y. Wang & K. Zhou (2011). "Inia geoffrensis". IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. International Union for Conservation of Nature and Natural Resources. Archived from the original on 2019-05-31. Retrieved 2018-10-29.
  8. ^ Rice, D. W. (1998). Marine mammals of the world: systematics and distribution. Society of Marine Mammalogy Special Publication Number 4. p. 231.
  9. ^ "List of Marine Mammal Species and Subspecies - Society for Marine Mammalogy". www.marinemammalscience.org. Retrieved 2017-09-01.
  10. ^ Gravena, Waleska; Farias, Izeni P.; Silva, Maria N. F. da; Silva, Vera M. F. da; Hrbek, Tomas (2014-06-01). "Looking to the past and the future: were the Madeira River rapids a geographical barrier to the boto (Cetacea: Iniidae)?". Conservation Genetics. 15 (3): 619–629. doi:10.1007/s10592-014-0565-4. ISSN 1566-0621. S2CID 14569447.
  11. ^ "Bolivia enacts law to protect Amazon pink dolphins". BBC News. 18 September 2012.
  12. ^ Robineau, Daniel; Buffrénil, Vivian, de (2003). "Early descriptions of whales: D'Orbigny, A. 1834. Note on a new cetacean genus, from the rivers of the central part of South America. [Notice sur un nouveau genre de cétacé, des rivières du centre de l'Amèrique méridionale. Nouvelles annales du Muséum d'histoire naturelle, 3:28–36]". The Journal of Cetacean Research and Management. 5 (3): 209–212. Retrieved 7 December 2013.
  13. ^ a b Aliaga-Rossel, Enzo, et al. "Stomach Content of a Juvenile Bolivian River Dolphin (Inia Geoffrensis Boliviensis) from the Upper Madeira Basin, Bolivia." Aquatic Mammals, vol. 36, no. 3, September 2010, pp. 284-287.
  14. ^ Yirka, Bob (May 5, 2022). "Bolivian river dolphins observed playing with an anaconda". Phys.org.
  15. ^ Entiauspe‐Neto, Omar M.; Reichle, Steffen; dos Rios, Alejandro (12 April 2022). "A case of playful interaction between Bolivian River Dolphins with a Beni Anaconda". Ecology. 103 (8): e3724. doi:10.1002/ecy.3724. PMID 35412650. S2CID 248099710.
  16. ^ a b Gravena, Waleska & Farias, Izeni & N. F. da Silva, Maria & da Silva, Vera & Hrbek, Tomas. (2014). Looking to the past and the future: Were the Madeira River rapids a geographical barrier to the boto (Cetacea: Iniidae)?”. Conservation Genetics. Web.
  17. ^ Wilke, Carolyn (2022-05-02). "An Anaconda's Play Date With Dolphins Took a Strange Turn". The New York Times. ISSN 0362-4331. Retrieved 2022-05-09.
  18. ^ Entiauspe‐Neto, Omar M.; Reichle, Steffen; dos Rios, Alejandro (2022-04-12). "A case of playful interaction between Bolivian River Dolphins with a Beni Anaconda". Ecology. 103 (8): e3724. doi:10.1002/ecy.3724. ISSN 0012-9658. PMID 35412650. S2CID 248099710.
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Bolivian river dolphin: Brief Summary ( англиски )

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The Bolivian river dolphin (Inia boliviensis) is a species of the genus Inia.

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Inia boliviensis ( шпански; кастиљски )

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El delfín boliviano (Inia boliviensis) es una especie de delfín del género Inia endémico de Bolivia. Tradicionalmente se consideraba una subespecie de la especie Inia geoffrensis,[1]​ pero estudios genéticos y el aislamiento geográfico sugieren que se trata de una especie diferente.[2]​ En base a estos estudios se calculó la separación de I. geoffrensis desde el Plioceno hace 3.1 millones de años.[3]​ Sin embargo, debido a la evidencia insuficiente para ser clasificada como especie diferente debido al pequeño tamaño de las muestras recolectadas para los estudios y la evidencia de flujo genético unidireccional a través de los rápidos de Teotonio con presencia de ejemplares de I. boliviensis en la cuenca baja del río Madeira;[4]​ la Sociedad de Mastozoología Marina y la IUCN lo siguen considerando como subespecie hasta que no se aporte evidencia concluyente.[5][6]

Se distribuye en la cuenca alta del río Madeira en Bolivia. Está confinado al río Mamoré y su principal afluente el Iténez, incluyendo la zona baja de sus tributarios entre los 100 y 300 msnm. La subespecie parece haberse aislado de las demás a causa de los 400 km de rápidos desde Porto Velho sobre el río Madeira hasta Riberalta sobre el río Beni en Bolivia.[7]

Se diferencia morfológicamente de I. geoffrensis por el mayor número de dientes, mayor tamaño y una cavidad craneana más pequeña.[8]

Los estudios acerca de su biología son escasos. En uno de ellos se examinó el contenido gástrico de dos cadáveres, en el cual se encontró al menos doce especies de peces pertenecientes a cuatro familias: Doradidae (67%), Heptapteridae (17%), Auchenipteridae (8%) y Characidae (subfamilia Tetragonopterinae, 8%).[9]

Fue declarado mediante ley n.º 284 Patrimonio Natural del Estado Plurinacional de Bolivia el 18 de septiembre de 2012[10]

Véase también

Referencias

  1. Wilson, Don E.; Reeder, DeeAnn M., eds. (2005). «Inia geoffrensis boliviensis». Mammal Species of the World (en inglés) (3ª edición). Baltimore: Johns Hopkins University Press, 2 vols. (2142 pp.). ISBN 978-0-8018-8221-0.
  2. Martínez-Agüero, M., S. Flores-Ramírez, and M. Ruiz-García (2006). «First report of major histocompatibility complex class II loci from the Amazon pink river dolphin (genus Inia. Genetics and Molecular Research 5 (3): 421-431. PMID 17117356. Archivado desde el original el 26 de septiembre de 2011. Consultado el 18 de enero de 2011.
  3. Hollatz, et al (abril de 2011). «The Amazon River system as an ecological barrier driving genetic differentiation of the pink dolphin (Inia geoffrensis)». Biological Journal of the Linnean Society (en inglés) 102 (4): 812-827. doi:10.1111/j.1095-8312.2011.01616.x.
  4. Gravena et al (enero de 2014). «Looking to the past and the future: were the Madeira River rapids a geographical barrier to the boto (Cetacea: Iniidae)?». Conservation Genetics (en inglés) 15 (3): 619-629. doi:10.1007/s10592-014-0565-4.
  5. Reeves, R.R., Jefferson, T.A., Karczmarski, L., Laidre, K., O’Corry-Crowe, G., Rojas-Bracho, L., Secchi, E.R., Slooten, E., Smith, B.D., Wang, J.Y. & Zhou, K. (2008). «Inia geoffrensis». Lista Roja de especies amenazadas de la UICN 2008 (en inglés). ISSN 2307-8235. Consultado el 6 de marzo de 2009.
  6. Committee on Taxonomy (septiembre de 2017). «List of Marine Mammal Species and Subspecies». Society for Marine Mammalogy (en inglés).
  7. Rice DW (1998). Wartzok D, ed. Marine mammals of the world: systematics and distribution (en inglés). Lawrence, KS. USA: Society for Marine Mammalogy, Special Publication Number 4. p. 231. ISBN 1891276034.
  8. Enzo Aliaga-Rossel. Situación actual del delfín de río (Inia geoffrensis) en Bolivia, vol 38, número 2: pp. 167-177, Octubre de 2003
  9. Aliaga-Rossel, Enzo. Content of a Juvenile Bolivian River Dolphin (Inia geoffrensis boliviensis) from the Upper Madeira Basin, Bolivia, julio de 2010. faqs.org
  10. Asamblea Legislativa del Estado Plurinacional de Bolivia http://www.diputados.bo/images/docs/leyes/Ley_N_284.pdf
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Inia boliviensis: Brief Summary ( шпански; кастиљски )

добавил wikipedia ES

El delfín boliviano (Inia boliviensis) es una especie de delfín del género Inia endémico de Bolivia. Tradicionalmente se consideraba una subespecie de la especie Inia geoffrensis,​ pero estudios genéticos y el aislamiento geográfico sugieren que se trata de una especie diferente.​ En base a estos estudios se calculó la separación de I. geoffrensis desde el Plioceno hace 3.1 millones de años.​ Sin embargo, debido a la evidencia insuficiente para ser clasificada como especie diferente debido al pequeño tamaño de las muestras recolectadas para los estudios y la evidencia de flujo genético unidireccional a través de los rápidos de Teotonio con presencia de ejemplares de I. boliviensis en la cuenca baja del río Madeira;​ la Sociedad de Mastozoología Marina y la IUCN lo siguen considerando como subespecie hasta que no se aporte evidencia concluyente.​​

Se distribuye en la cuenca alta del río Madeira en Bolivia. Está confinado al río Mamoré y su principal afluente el Iténez, incluyendo la zona baja de sus tributarios entre los 100 y 300 msnm. La subespecie parece haberse aislado de las demás a causa de los 400 km de rápidos desde Porto Velho sobre el río Madeira hasta Riberalta sobre el río Beni en Bolivia.​

Se diferencia morfológicamente de I. geoffrensis por el mayor número de dientes, mayor tamaño y una cavidad craneana más pequeña.​

Los estudios acerca de su biología son escasos. En uno de ellos se examinó el contenido gástrico de dos cadáveres, en el cual se encontró al menos doce especies de peces pertenecientes a cuatro familias: Doradidae (67%), Heptapteridae (17%), Auchenipteridae (8%) y Characidae (subfamilia Tetragonopterinae, 8%).​

Fue declarado mediante ley n.º 284 Patrimonio Natural del Estado Plurinacional de Bolivia el 18 de septiembre de 2012

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Inia geoffrensis boliviensis ( баскиски )

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Inia geoffrensis boliviensis Inia generoko animalia da. Artiodaktiloen barruko Iniidae familian sailkatuta dago.

Aditu batzuk espezietzat (Inia boliviensis izenpean) izan arren, gehienek- IUCNek tartean- Amazonasko Inia geoffrensis espeziearen azpiespezietzat jotzen dute.

2012ko irailean, Evo Morales Boliviako presidenteak herrialdeko ikur izendatu zuen.[1]

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Ikus, gainera

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Inia geoffrensis boliviensis: Brief Summary ( баскиски )

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Inia geoffrensis boliviensis Inia generoko animalia da. Artiodaktiloen barruko Iniidae familian sailkatuta dago.

Aditu batzuk espezietzat (Inia boliviensis izenpean) izan arren, gehienek- IUCNek tartean- Amazonasko Inia geoffrensis espeziearen azpiespezietzat jotzen dute.

2012ko irailean, Evo Morales Boliviako presidenteak herrialdeko ikur izendatu zuen.

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Inia boliviensis ( италијански )

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Il delfino boliviano (Inia boliviensis (d'Orbigny, 1834)) è un delfino di fiume endemico della Bolivia.

Tassonomia

Per molto tempo è stato considerato solo una sottospecie della specie Inia geoffrensis. Studi genetici hanno dimostrato che si tratta di una specie distinta, che sono isolate geneticamente e fisicamente da cascate insuperabili per qualsiasi delfino [1]. Comunque, alcune pubblicazioni (inclusa l'IUCN) continuano a considerarlo una sottospecie[2]. Uno studio della sequenza del DNA mitocondriale ha stimato che il tempo di divergenza dalla Inia geoffrensis è di circa 2,9 milioni di anni[3].

Descrizione

Si differenzia dalle altre specie per il maggior numero di denti, le dimensioni maggiori e una cavità cranica minore [4]. Gli studi sulla sua biologia sono scarsi. In uno di questi è stato esaminato il contenuto gastrico di due cadaveri nei quali si sono trovate almeno 12 specie di pesci appartenenti a 4 famiglie: Doradidae (67%), Eptapteridae (17%), Auchenipteridae (8%) e Characidae (8%)[5].

Distribuzione

Si trova nella parte alta del bacino del fiume Madeira (In Bolivia). È ristretta al fiume Mamoré e al suo principale affluente (fiume Guaporé), includendo la zona bassa dei suoi tributari fra i 100 e i 300 m s.l.m.. La sottospecie pare che si sia isolata dalle altre a causa dei 400 km di rapide tra Porto Velho fino alla Riberalta sul fiume Beni in Bolivia [6].

Note

  1. ^ Martínez-Agüero, M., S. Flores-Ramírez, and M. Ruiz-García, First report of major histocompatibility complex class II loci from the Amazon pink river dolphin (Genus Inia) (PDF), in Genetics and Molecular Research, vol. 5, 2006, 421-431. URL consultato il 15 marzo 2015 (archiviato dall'url originale il 26 settembre 2011).
  2. ^ Reeves, R.R., Jefferson, T.A., Karczmarski, L., Laidre, K., O’Corry-Crowe, G., Rojas-Bracho, L., Secchi, E.R., Slooten, E., Smith, B.D., Wang, J.Y. & Zhou, K., Inia geoffrensis, su iucnredlist.org, 2008. URL consultato il 13 marzo 2015.
  3. ^ Tomas Hrbek; Vera Maria Ferreira da Silva; Nicole Dutra; Waleska Gravena; Anthony R. Martin; Izeni Pires Farias, A New Species of River Dolphin from Brazil or: How Little Do We Know Our Biodiversity, in PLOS ONE, vol. 9, 2014.
  4. ^ Enzo Aliaga-Rossel, Situación actual del delfín de río (Inia geoffrensis) en Bolivia, in Ecologia en Bolivia, vol. 38, 2003, 167-177.
  5. ^ Enzo Aliaga-Rossel, Stomach Content of a Juvenile Bolivian River Dolphin (Inia geoffrensis boliviensis) from the Upper Madeira Basin, Bolivia, in Aquatic Mammals, vol. 20, 2010.
  6. ^ Rice DW, Marine mammals of the world: systematics and distribution, Society for Marine Mammalogy, Special Publication Number 4, 1998, p. 231, ISBN 1891276034.

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Inia boliviensis: Brief Summary ( италијански )

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Il delfino boliviano (Inia boliviensis (d'Orbigny, 1834)) è un delfino di fiume endemico della Bolivia.

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Inia boliviensis ( португалски )

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Inia boliviensis é uma espécie de golfinho fluvial do gênero Inia. Pode ser encontrada na Bolívia e marginalmente no Brasil (no estado de Rondônia).

Nomenclatura e taxonomia

Em 1824, Alcide d'Orbigny descreveu o Inia boliviensis como uma espécie distinta, e estabelecendo o termo genérico Inia.[1] Posteriormente o táxon foi classificado como uma subespécie do Inia geoffrensis e esse arranjo taxonômico perdurou até a década de 1970 sem contestação.

Em 1977, uma análise morfológica e morfométrica com base em indivíduos depositados em museus considerou a população boliviana uma espécie distinta.[2] A distinção foi contestada já que os caracteres utilizados eram muito variáveis para serem utilizados na distinção das populações em duas espécies distintas.[3] Com base na morfologia do crânio, em 1994, foi proposto novamente que o I. g. boliviensis representava uma espécie distinta,[4] entretanto, devido ao pequeno número de espécimes analisados a conclusão foi enviesada.[5]

Alguns autores seguiram o arranjo taxonômico de considerar a população boliviana como uma espécie distinta,[6] enquanto outros continuaram a tratá-la como uma subespécie.[7]

No início da década de 2000, a hipótese de duas espécies válidas foi analisada com estudos moleculares e genéticos. Análises de DNA mitocondrial, genes do citocromo b mitocondrial e sequências de intron nuclear demonstraram uma grande variação entre a população da Bolívia e a do Amazonas-Orinoco, demonstrando uma distinção em nível de espécie.[8][9][10][5] Um novo estudo morfológico também demonstrou a existência de duas espécies válidas.[11]

Distribuição geográfica e habitat

A espécie está restrita na bacia do alto rio Madeira, com as quedas d'água de Teotônio, entre Guajará-Mirim e Porto Velho em Rondônia, formando uma barreira geográfica de isolamento da população. Além do curso principal do rio madeira, a espécie é registrada no rio Beni, na bacia do Guaporé ou Iténez, juntamente com os afluentes Verde e Iporuporé, e na bacia do Mamoré e seus tributários e afluentes: Pirai, Grande, Ichilo, Chapare, Ibaré, Tijumachi, Apere, Yacuma e Yata.[12]

Conservação

Em setembro de 2012, o presidente da Bolívia Evo Morales decretou uma lei de proteção ao boto e o declarou um tesouro nacional.[13]

Referências

  1. d'ORBIGNY, A.M. (1834). «Notice sur un nouveau genre de cetacé des rivieres du centre de l'Amerique meridionale». Nouveau Annales du Musee d'Historie Naturel de Paris. 3: 28-36
  2. PILLERI, G.; GHIR, M. (1977). «Observations on the Bolivian, Inia boliviensis (D'Orbigny, 1834) and the Amazonian bufeo, Inia geoffrensis (Blainville 1817), with a description of a new subspecies (Inia geoffrensis humboldtiana)». Investigations on Cetacea. 8: 11-76 !CS1 manut: Nomes múltiplos: lista de autores (link)
  3. CASINOS, A.; OCAÑA, J. (1979). «A craniometrical study of the genus Inia d'Orbigny, 1834 (Cetacea, Platanistoidea)». Saugetierkundliche Mitteilungen. 27: 194-206 !CS1 manut: Nomes múltiplos: lista de autores (link)
  4. da SILVA, V.M.F. (1994). Aspects of the biology of the Amazonian dolphins genus Inia and Sotalia fluviatilis. PhD Dissertation, Univ. of Cambridge. pp. 327.
  5. a b RUIZ-GARCIA, M.; CABALLERO, S.; MARTINEZ-AGÜERO, M.; SHOSTELL, J.M. (2008). KOVEN, V. (ed.), ed. Population Genetics Research Progress. Hauppauge: Nova Science Publisher, inc !CS1 manut: Nomes múltiplos: lista de autores (link)
  6. NOVAK, R.M. (1999). _____, ed. Walker’s Mammals of the World 6 ed. Baltimore: Johns Hopkins University Press. 1936 páginas. ISBN 0-8018-5789-9
  7. Rice DW (1998) Marine mammals of the world – Systematics and distribution. Special Publication Number 4, Beaufort, NC: The Society for Marine Mammalogy.
  8. HAMILTON, H.; CABALLERO, S.; COLLINS, A.G.; BROWNELL Jr, R.L.; (2001). «Evolution of river dolphins». Proceedings of the Real Society of London B. 268: 549-556 !CS1 manut: Nomes múltiplos: lista de autores (link)
  9. BANGUERA-HINESTROZA, E.; CÁRDENAS, H.; RUIZ-GARCÍA, M.; MARMONTEL, M.; GAITÁN, E.; VÁZQUEZ, R.; GARCÍA-VALLEJO, F. (2002). «Molecular identification of evolutionarily significant units in the Amazon River dolphin Inia sp. (Cetacea: Iniidae)». Journal of Heredity. 93 (5): 312-322 !CS1 manut: Nomes múltiplos: lista de autores (link)
  10. RUIZ-GARCÍA, M.; MURILLO, A.; CORRALES, C.; ROMERO-ALEÁN, N.; ÁLVAREZ-PRADA, D. (2007). «Genética de poblaciones amazónicas: la historia evolutiva del jaguar, ocelote, delfín rosado, mono lanudo y piurí, reconstruida a partir de sus genes». Animal Biodiversity and Conservation. 30 (2): 115–130 !CS1 manut: Nomes múltiplos: lista de autores (link)
  11. RUIZ-GARCÍA, M.; BANGUERA, E.; CARDENAS, H. (2006). «Morphological analysis of three Inia (Cetacea: Iniidae) populations from Colombia and Bolivia». Acta Theriologica. 51 (4): 411–426. doi:10.1007/BF03195188 !CS1 manut: Nomes múltiplos: lista de autores (link)
  12. REEVES, R.R.; JEFFERSON, T.A.; KARCZMARSKI, L.; LAIDRE, K.; O’CORRY-CROWE, G.; ROJAS-BRACHO, L.; SECCHI, E.R.; SLOOTEN, E.; SMITH, B.D.; WANG, J.Y.; ZHOU, K. (2011). Inia geoffrensis (em inglês). IUCN 2012. Lista Vermelha de Espécies Ameaçadas da IUCN de 2012 . Página visitada em 1 de maio de 2013..
  13. «Bolivia enacts law to protect Amazon pink dolphins». BBC News. 18 de setembro de 2012. Consultado em 2 de maio de 2013

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Inia boliviensis: Brief Summary ( португалски )

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Inia boliviensis é uma espécie de golfinho fluvial do gênero Inia. Pode ser encontrada na Bolívia e marginalmente no Brasil (no estado de Rondônia).

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Bolivya nehir yunusu ( турски )

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Bolivya nehir yunusu (Inia geoffrensis boliviensis), Amazon nehir yunusu'nun alt türü olan, Bolivya'da ve Brezilya'nın güneybatı bölgesinde yaşayan nehir yunusu. 2008 yılında moleküler düzeydeki çalışmaların ardından ayrı bir tür olarak teyit edilmiştir.

Bu yunusun Inia geoffrensis türünden farklı olduğunu savunan araştırmacılar ve bilimsel kuruluşlar da mevcuttur.[1][2][3]

Eylül 2012'de, Bolivya cumhurbaşkanı Evo Morales bu yunusu ulusal zenginlik kapsamına katarak korunmasına yönelik kanunlar çıkarmıştır.[4]

Keşif

Fransız doğa bilimci ve paleontolojist Alcide Dessalines d'Orbigny, bu yunusu 1826-1833 yılları arasında Güney Amerika'da keşfetmiştir.[5] Fransa'ya 1834 yılında döndüğünde kendi keşfettiği bilimsel keşiflerine Inia boliviensis türünü de eklemiştir. 1847 yılında d'Orbigny ve Paul Gervais bu yeni türü "Delphinius geoffrensis" yani Amazon nehir yunusu) ile karşılaştırmışlar ve bu iki yunus türünün çok yakın olduğuna karar vermişlerdir.[6]

1973 yılında Bolivya'daki akarsularda bu yunusa ait dişler bulunmuştur. Bu tarihten itibaren "Bolivya nehir yunusu" adını alan Inia geoffrensis boliviensis bu isimle literatüre girmiştir. Buna karşın bu nehir yunusunun taksomonisinde bir fikir birliği bulunmamaktadır.[7]

Hakkında

Hayvanın boyunun 208 ile 216 cm arasında değiştiği ve üst çenede 31-35 diş bulunduğu rapor edilmiştir.[8] Uzun bir burna sahip olan bu canlı türünde, erkek ve dişiler arasında vücut boyutu ve şekli, renk veya desen bakımından farklılıklar görülür (Seksüel dimorfizm). Fiziksel özellikleri bakımından Amazon nehir yunusu ile benzerlikler taşır. Bununla birlikte bu canlılarla ilgili ayrıntılı çalışmalar mevcut olmayıp standart verilerek ulaşmak mümkün değildir.

Bolivya nehir yunusları genellikle Bolivya'daki göl ve nehirlerde yaşamakta ve buradaki besinlerle yaşamlarını devam ettirmektedir. Cinsin diğer üyeleri gibi bu canlıların da temel besin kaynağı balıktır.[8][9]

Koruma

Bölgedeki baraj inşaatları bu canlıların yaşamlarına tehdit oluşturmaktadır. Bu barajlar nedeniyle canlıların doğal besin kaynakları yok olmaya yüz tutmuştur. Bu tehditlere karşı Bolivya hükûmeti bu yunus türü için çeşitli önlemler almıştır. Buna yönelik olarak Temmuz 1999'da çıkartılan 25458 nolu Kararname ile bölgedeki avcılık ve balıkçılık risk olarak kabul edilmiş ve ulusal zenginliğe karşı suç olarak tanımlanarak yasaklanmıştır. Bu kararı takiben 2008 yılında çıkan kararda da bu yunus cinsi Bolivya'nın ulusal mirası kapsamı altına alınmıştır. Tüm bunlara karşın Dünya Doğa ve Doğal Kaynakları Koruma Birliği bu cinsi, bilimsel verilerin eksik olması sebebiyle henüz bağımsız bir tür olarak kabul etmemiştir.[8]

Bölgede yaşayan 1400 ila 4000 arasında Bolivya nehir yunusu olduğu tahmin edilmektedir.[8]

Galeri

Ayrıca bakınız

Kaynakça

  1. ^ Martínez-Agüero, M.; S. Flores-Ramírez; M. Ruiz-García (2006). "First report of major histocompatibility complex class II loci from the Amazon pink river dolphin (genus Inia)" (PDF). Genetics and Molecular Research. 5 (3), s. 421–431. PMID 17117356.
  2. ^ Hrbek, Tomas; Da Silva, Vera Maria Ferreira; Dutra, Nicole; Gravena, Waleska; Martin, Anthony R.; Farias, Izeni Pires (22 Ocak 2014). Turvey, Samuel T. (Ed.). "A New Species of River Dolphin from Brazil or: How Little Do We Know Our Biodiversity". PLOS ONE. Cilt 9, s. e83623. doi:10.1371/journal.pone.0083623. PMC 3898917 $2. PMID 24465386.
  3. ^ R.R. Reeves; T.A. Jefferson; L. Karczmarski; K. Laidre; G. O'Corry-Crowe; L. Rojas-Bracho; E.R. Secchi; E. Slooten; B.D. Smith; J.Y. Wang; K. Zhou (2011). "Inia geoffrensis". IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. International Union for Conservation of Nature and Natural Resources.
  4. ^ "Bolivia enacts law to protect Amazon pink dolphins". BBC News. 18 Eylül 2012.
  5. ^ M. Ruiz-García, S. Caballero, M. Martinez-Agüero, J.M. Shostell JM: Molecular differentiation among Inia geoffrensis and Inia boliviensis (Iniidae, Cetacea) by means of nuclear intron sequences. In: V.T. Koven (Herausgeber): Population Genetics Research Progress. Boca Raton, Nova Publishers 2008; S. 177–203.
  6. ^ Inia geoffrensis (Blainville, 1817), Erişim tarihi: 18 Ekim 2016.
  7. ^ Robineau, Daniel; Buffrénil, Vivian, de (2003). "Early descriptions of whales: D'Orbigny, A. 1834. Note on a new cetacean genus, from the rivers of the central part of South America. [Notice sur un nouveau genre de cétacé, des rivières du centre de l'Amèrique méridionale. Nouvelles annales du Muséum d'histoire naturelle, 3:28–36]". The Journal of Cetacean Research and Management. IWC. 5 (3), s. 209–212. Erişim tarihi: December 2013. Tarih değerini gözden geçirin: |accessdate= (yardım)
  8. ^ a b c d V.M.F. da Silva, A.R. Martin: Family Iniidae (Amazon River Dolphins); Bolivian Boto Inia boliviensis In: Don E. Wilson, Russell A. Mittermeier: Handbook of the Mammals of the World. 4. Sea Mammals. Lynx Edicions, Barcelona 2014; S. 378. ISBN 978-84-96553-93-4.
  9. ^ Tomas Hrbek, Vera Maria Ferreira Da Silva, Nicole Dutra, Waleska Gravena, Anthony R. Martin, Izeni Pires Farias: A New Species of River Dolphin from Brazil or: How Little Do We Know Our Biodiversity. In Samuel T. Turvey, PLoS ONE 9, 2014: e83623. doi:10.1371/journal.pone.0083623.

Dış bağlantılar

 src= Wikimedia Commons'ta Bolivya nehir yunusu ile ilgili medyaları bulabilirsiniz.
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Bolivya nehir yunusu: Brief Summary ( турски )

добавил wikipedia TR

Bolivya nehir yunusu (Inia geoffrensis boliviensis), Amazon nehir yunusu'nun alt türü olan, Bolivya'da ve Brezilya'nın güneybatı bölgesinde yaşayan nehir yunusu. 2008 yılında moleküler düzeydeki çalışmaların ardından ayrı bir tür olarak teyit edilmiştir.

Bu yunusun Inia geoffrensis türünden farklı olduğunu savunan araştırmacılar ve bilimsel kuruluşlar da mevcuttur.

Eylül 2012'de, Bolivya cumhurbaşkanı Evo Morales bu yunusu ulusal zenginlik kapsamına katarak korunmasına yönelik kanunlar çıkarmıştır.

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볼리비아강돌고래 ( корејски )

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볼리비아강돌고래[1] (Inia boliviensis)는 고래목에 속하는 남아메리카 강돌고래의 일종이다. 아마존강돌고래의 아종으로 간주해 왔으나 2012년 이후 별도의 종으로 분류하고 있다.[2]

계통 분류

다음은 비남아시아 강돌고래의 계통 분류이다.[1]

비-남아시아 강돌고래 남아메리카
강돌고래 아마존강돌고래속      

아라과이아강돌고래

       

아마존강돌고래

         

볼리비아강돌고래

       

라플라타돌고래

     

양쯔강돌고래

   

각주

  1. Hrbek, Tomas; Da Silva, Vera Maria Ferreira; Dutra, Nicole; Gravena, Waleska; Martin, Anthony R.; Farias, Izeni Pires (2014년 1월 22일). Turvey, Samuel T., 편집. “A New Species of River Dolphin from Brazil or: How Little Do We Know Our Biodiversity”. 《PLOS ONE9: e83623. doi:10.1371/journal.pone.0083623. PMC 3898917. PMID 24465386.
  2. Committee on Taxonomy. 2012. List of marine mammal species and subspecies. Society for Marine Mammalogy, www.marinemammalscience.org, consulted on May 6, 2012.
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