Fish and aquatic news

This might not be news for some of you, but for those of you that has missed it: a new species of manatee might have been encountered by Dr Marc van Roosmalen in the Brazilian Amazon! Not only is this believed to be an entirely new species of manatee; it is also the smallest living member of the order Sirenia, measuring no more than 130 cm as an adult.

All Picture by: Marc van Roosmalen

In September 2002, wildlife-researcher Dr Marc van Roosmalen collected a complete skull from a recently killed specimen, but it would take an additional two years before he could finally photograph, film and examine a live specimen in its natural environment. As per usual when a new mammal is “discovered”, the species is only new to the scientific community, not to the locals of the area, and the skull of the specimen collected by van Roosmalen came from a manatee that had been killed and eaten by the locals.

Van Roosmalen has proposed that the so called Dwarf manatee should be considered a separate species of manatee and has given it the name Trichechus bernhardi, but others have suggested that this peculiarly small manatee is actually an immature Amazonian manatee (Trichechus inunguis). Both animals are very closely related and mitochondrial DNA (mtDNA) comparisons have failed to reveal any difference between the two.

According to van Roosmalen’s scientific description of the dwarf manatee, it lives in one of the tributaries of Rio Aripuanã where it inhabits shallow, fast running water. This distinguishes it from the Amazonian manatee which is known to prefer deep and slow moving waters and is found throughout a much larger part of South America. There is also a difference in diet; both animals feed on aquatic plants but on different species. In addition to this, there is a significant disparity in both proportions and colour. The dwarf manatee weighs about 60 kg as an adult and has a dark, almost black, body adorned with a white patch on the abdomen. The Amazonian manatee is much larger than the Dwarf manatee and can weigh over 500 kg. This difference has been used by both sides; those who believe that it is a separate species and those who believe it to be an immature Amazonian manatee.

Regardless of whether this is truly is new species or merely an immature version of the Amazonian manatee, I certainly agree with Christopher Collinson’s comments on the Tetrapod Zoology blog: “On a side note, why the heck are those dwarf manatees so friggen adorable? They have way more cutesy factor than any one animal should be allowed to posess, its at least like a million times more than regular old plain Jane manatees.”

Picture courtesy of: Marc van Roosmalen