Publisher : Biodiversity Journal
Place of publication :
Publication year : 2015
Thematic : Species
Language : English
Note
Here I announce the discovery of a whole new ecosystem in the central-southern part of the
Brazilian Amazon: the Rio Aripuanã Basin. Overall, it seems to have created more ecological
niches than any other river basin in the Amazon, in particular so to aquatic and non-volant
terrestrial mammals. This is plausibly explained for by the unique geo-morphological history
of the region. During the Pliocene and Early Pleistocene the entire area to the southeast of
the Rio Madeira contained one huge clear-water system that was drained toward the south
into the Atlantic Ocean. In the course of several million years a biome quite different from
the rest of Amazonia could evolve in this drainage system. Living relicts from ancient times
that happened to survive in isolation here, are: a dwarf manatee here described as Trichechus
pygmaeus n. sp., a dolphin locally called “boto roxo†that is suspected to be closer related to
marine Rio Plata dolphins Pontoporia blainvillei (Gervais et d'Orbigny, 1844) than to
Amazonian dolphins of the genus Inia (d'Orbigny, 1834), a black dwarf tapir (Tapirus
pygmaeus Van Roosmalen, 2013, with T. kabomani Cozzuol et al., 2013 as junior name), a
dwarf marmoset Callibella humilis Van Roosmalen et Van Roosmalen, 2003, a new monospecific
genus of Callitrichidae that stands at the base of the phylogenetic tree of all extant
marmosets (i.e., Cebuella Gray, 1866, Mico Lesson, 1840, and Callithrix Erxleben, 1777), a
giant striped paca here described as Agouti silvagarciae n. sp., and an arboreal giant anteater
spotted in the wild but remains to be collected and described (Myrmecophaga n. sp.). A
number of other, more advanced mammalian species discovered in the Rio Aripuanã Basin,
among which a third species of brocket here described as Mazama tienhoveni n. sp., evolved
after a dramatic vicariance took place about 1-1.8 MYA (million years ago), the break-through
of the continental watershed by the proto-Madeira River during one of the glacial epochs of
the Middle Pleistocene. It marked the birth of the modern fast-flowing Rio Madeira, in terms
of total discharge the biggest tributary of the Amazon proper and the second strongest river
barrier in the entire Amazon Basin. Furthermore, current threats to the environment in this
sparsely inhabited and poorly explored river basin will be addressed. We intend to have this
‘lost world’ preserved as a UNESCO Natural World Heritage Reserve through the divulgation
of new, hitherto not yet identified mammals that it appears to harbor.
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Keywords : ecosystem-based-fisheries-management
Encoded by : Pauline Carmel Joy Eje
