|Scientific classification (disputed)|
The dwarf manatee (Trichechus "pygmaeus", or mistakenly Trichechus bernhardi) is a possible species of manatee found in the freshwater habitats of the Amazon, though restricted to one tributary of the Aripuanã River. According to Marc van Roosmalen, the scientist who proposed it as a new species, it lives in shallow, fast-running water, and feeds on different species of aquatic plants from the Amazonian manatee, which prefers deeper, slower-moving waters and the plants found there. The dwarf manatee reportedly migrates upriver during the rainy season when the river floods to the headwaters and shallow ponds. Based on its small range, the dwarf manatee is suggested to be considered critically endangered, but at present it is not recognized by the IUCN.
The dwarf manatee is typically about 130 cm (4.3 ft) long, and weighs about 60 kg (130 lb), making it the smallest extant sirenians. It is overall very dark, almost black, with a white patch on the abdomen. It may actually represent an immature Amazonian manatee, but it is reported to differ in proportions and colour. It is, however, at least very closely related, as mtDNA has failed to reveal any difference between the two. Mutation rates in manatees – if the dwarf manatee is distinct – suggests a divergence time of less than 485,000 years. Daryl Domning, a Smithsonian Institution research associate and the world's foremost experts on manatee evolution, has stated that the DNA evidence actually proves that these merely are immature Amazonian manatees.
Disregarding its questionable validity as a species, the proposed name Trichechus pygmaeus is problematic. A formal description using that name was submitted to Nature, but it was rejected and consequently the article has only been published online. This has resulted in the invalidation of the name following chapter 3, article 8.6 of the ICZN Code. The paper containing the formal description of Trichechus pygmaeus was eventually published in the Biodiversity Journal in 2015.
- International Union for Conservation of Nature (2008). IUCN Red List. Accessed November 09, 2009.
- William. (2008). Interview with Marc van Roosmalen. aquaticcommunity.com. Accessed November 09, 2009.
- van Roosmalen, M. G. M. A new species of living manatee from the Amazon.. Accessed on March 15, 2008.
- How Manatees Evolved. manateebrain.org. Accessed 2008-07-27
- Trials of a Primatologist. smithsonianmag.com. Accessed 2008-07-27
- International Commission on Zoological Nomenclature. (1999). International Code of Zoological Nomenclature. 4th edition. Accessed December 22, 2011.
- Marc G.M. van Roosmalen (2015). "Hotspot of new megafauna found in the Central Amazon: the lower Rio Aripuanã Basin" (PDF). Biodiversity Journal 6 (1): 219–244.
- Cryptomundo - (New Dwarf Manatee)
- Tetrapodzoology - (Multiple new species of large, living mammal (part II))
- Wildlife Extra