The dwarf manatee (''Trichechus pygmaeus'', or mistakenly ''Trichechus bernhardi'')William. (2008).
Interview with Marc van Roosmalen.
' aquaticcommunity.com. Accessed November 09, 2009. is a disputed species of

manatee Manatees (family Trichechidae, genus ''Trichechus'') are large, fully aquatic, mostly herbivorous marine mammals sometimes known as sea cows. There are three accepted living species of Trichechidae, representing three of the four living species ...

allegedly found in the freshwater habitats of the

Amazon Amazon most often refers to: * Amazons, a tribe of female warriors in Greek mythology * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon River, in South America * Amazon (company), an American multinational technology c ...

, though restricted to one

tributary A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drainage ...

of the

Aripuanã River Aripuanã River ( pt, Rio Aripuanã) is a river in the Mato Grosso and Amazonas states in north-western Brazil. It is a tributary of the Madeira River in the Amazon Basin. The town of Novo Aripuanã is located on its banks where it merges into t ...

. According to

Marc van Roosmalen Dr. Marc van Roosmalen (born June 23, 1947) is a Dutch-Brazilian primatologist. He was elected as one of the "Heroes of the Planet" by ''Time'' magazine in 2000. His research has led to the identification of several new monkey species, as well a ...

, 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 The Amazonian manatee (''Trichechus inunguis'') is a species of manatee that lives in the Amazon Basin in Brazil, Peru, Colombia and Ecuador. It has thin, wrinkled brownish or gray colored skin, with fine hairs scattered over its body and a whit ...

, 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 if indeed a separate species, but is not recognized by the

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

.International Union for Conservation of Nature (2008).
IUCN Red List
'' Accessed November 09, 2009. The dwarf manatee is described as typically being about long and weighing about , which would make it the smallest

extant Extant is the opposite of the word extinct. It may refer to: * Extant hereditary titles * Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English * Extant taxon, a taxon which is not extinct, ...

sirenia The Sirenia (), commonly referred to as sea-cows or sirenians, are an order of fully aquatic, herbivorous mammals that inhabit swamps, rivers, estuaries, marine wetlands, and coastal marine waters. The Sirenia currently comprise two distinct f ...

n. It is supposedly very dark, almost black, with a white patch on the

abdomen The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the torso. ...

. 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 Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial DNA ...

has failed to reveal any difference between the two.

Mutation rate In genetics, the mutation rate is the frequency of new mutations in a single gene or organism over time. Mutation rates are not constant and are not limited to a single type of mutation; there are many different types of mutations. Mutation rates ...

s in manatees – if the dwarf manatee is distinct – suggests a

divergence In vector calculus, divergence is a vector operator that operates on a vector field, producing a scalar field giving the quantity of the vector field's source at each point. More technically, the divergence represents the volume density of the ...

time of less than 485,000 years. Daryl Domning, a

Smithsonian Institution The Smithsonian Institution ( ), or simply the Smithsonian, is a group of museums and education and research centers, the largest such complex in the world, created by the U.S. government "for the increase and diffusion of knowledge". Founded ...

research associate and one of the world's foremost experts on manatee evolution, has stated that the DNA evidence actually proves that these are merely immature Amazonian manatees.

Taxonomy

The original description was submitted for publication to ''

Nature Nature, in the broadest sense, is the physics, physical world or universe. "Nature" can refer to the phenomenon, phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. ...

'', but it was rejected, and it was eventually published in the ''Biodiversity Journal'' in 2015.

References

External links

*Tetrapodzoology
new species of large, living mammal (part II))''
Sirenians Controversial mammal taxa Mammals described in 2015 {{afrotheria-stub