Biology Reference
In-Depth Information
4
3
1
0
o
2
2
0
o
5
1. Marañon River near Pebas, Loreto - Peru
2. Marañon River near Nauta, Loreto - Peru
4
0
o
3. Amazonas River near Santarém, Pará - Brazil
4. Mouth of Marowijne River - Surinamee/French
Guiana border
5. Guanabara Bay, Rio de Janeiro - Brazil
80
o
60
o
40
o
Figure 3. Type localities of
Sotalia
species from South America. Numbers correspond to those depicted
between parentheses in Figure 2.
All those species were described based on few individuals from single location, at a time
when barely anything was known about their ranges, so their diagnoses were incomplete and
full of inconsistencies. As more specimens were examined and more data on their distribution
were gathered, the three freshwater species were lumped into
Sotalia fluviatilis
, and the two
marine were grouped as
Sotalia guianensis
(True, 1889; Cabrera, 1961; Carvalho, 1963).
Later, some authors argued that the differences between
S. fluviatilis
and
S. guianensis
were too subtle and attributable to phenotypic variability, and that
Sotalia
should be regarded
as monotypic (Mitchell, 1975; Leatherwood & Reeves, 1983). This proposal was reinforced
by a morphometric study that concluded that differences between marine and riverine
Sotalia
were mainly a consequence of size variation, and concluded that they should be considered a
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