Bolivian river dolphin

Bolivian river dolphin
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Artiodactyla
Infraorder:	Cetacea
Family:	Iniidae
Genus:	Inia
Species:	I. geoffrensis
Subspecies:	I. g. boliviensis
Trinomial name
Inia geoffrensis boliviensis d'Orbigny, 1834

The Bolivian river dolphin (Inia geoffrensis boliviensis), a mammal, is a subspecies of the Amazon river dolphin. Although older publications and some recent publications^[1][2] consider the I. g. boliviensis population as distinct species from Inia geoffrensis, much of the scientific community, including the IUCN,^[3] consider them to be a subspecies of Inia geoffrensis. Current classification,^[4] therefore, considers them a single species, Inia geoffrensis, in the genus Inia, with three recognized subspecies. However, in 2012 the Society for Marine Mammalogy^[5] began considering the Bolivian (Inia geoffrensis boliviensis) and Amazonian (Inia geoffrensis geoffrensis) subspecies as full species Inia boliviensis and Inia geoffrensis. A recent study of mitochondrial DNA sequences gave an estimated time of divergence from I. geoffrensis geoffrensis of 2.9 million years ago, strengthening the argument for separate species status.^[2]

In September 2012, Bolivian President Evo Morales enacted a law to protect the dolphin and declared it a national treasure.^[6]

Drawings of the Bolivian river dolphin by d'Orbigny 1847

French naturalist and palaeontologist Alcide Dessalines d'Orbigny explored South America from 1826–1833, including a stay in Bolivia from 1831–1833. 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").^[7]

References