The species within Xenarthra (sloths, anteaters, and armadillos) are quintessential South American mammals. Of the three groups, Vermilingua (anteaters) contains the fewest extant and paleontological species. Here, we sampled and sequenced the entire mitochondrial genomes (mitogenomes) of two
Tamandua
species (
Tamandua tetradactyla
and
T. mexicana
) (
n
=74) from Central and South America, as well as
Myrmecophaga tridactyla
(
n
=41) from South America. Within
Tamandua
, we detected three different haplogroups. The oldest (THI) contained many specimens with the
T. tetradactyla
morphotype (but also several with the
T. mexicana
morphotype) and originated in southeastern South America (currently Uruguay) before moving towards northern South America, where the THII haplogroup originated. THII primarily contained specimens with the
T. mexicana
morphotype (but also several with the
T. tetradactyla
morphotype) and was distributed in Central America, Colombia, and Ecuador. THI and THII yielded a genetic distance of 4%. THII originated in either northern South America or “
in situ
” in Central America with haplogroup THIII, which consisted of ~50%
T. mexicana
and 50%
T. tetradactyla
phenotypes. THIII was mostly located in the same areas as THII, i.e., Central America, Ecuador, and Colombia, though mainly in the latter. The three haplogroups overlapped in Colombia and Ecuador. Thus,
T. tetradactyla
and
T. mexicana
were not reciprocally monophyletic. For this reason, we considered that a unique species of
Tamandua
likely exists, i.e.,
T. tetradactyla
. In contrast to
Tamandua
,
M. tridactyla
did not show different morphotypes throughout its geographical range in the Neotropics. However, two very divergent genetic haplogroups (MHI and MHII), with a genetic distance of ~10%, were detected. The basal haplogroup, MHI, originated in northwestern South America, whereas the more geographically derived haplogroup, MHII, overlapped with MHI, but also expanded into central and southern South America. Thus,
Tamandua
migrated from south to north whereas
Myrmecophaga
migrated from north to south. Our results also showed that temporal mitochondrial diversification for
Tamandua
began during the Late Pliocene and Upper Pleistocene, but for
Myrmecophaga
began during the Late Miocene. Furthermore, both taxa showed elevated levels of mitochondrial genetic diversity.
Tamandua
showed more evidence of female population expansion than
Myrmecophaga
.
...