Mantel test and geographic influence
Individuals from localities which are in close geographic proximity tend
to be more related to each other than individuals which are located
further away from each other, this is supported by the results of the
Mantel test. The Mantel tests showed that there is a relationship
between geographic distance and genetic distance in our samples. There
is a weak positive correlation in both cases, meaning that with greater
geographic distance the samples are slightly less related . This is
termed isolation by distance and is a common artefact in mygalomorph
spiders due to their poor dispersal abilities and sedentary lifestyles .
This is important information to note given the possible fragmentation
of the habitat due to land use changes.
This also leads to many species being considered short range endemics
and occuring at only one or a few localities . This is true for many of
the species considered here, except for S. astutus , S.
maraisi , S.leipldti and S. erythrognathus . Most of these
species have ranges of less than 10,000 km2 This is
vital as this makes these species a conservation concern as they are
more at risk of extinction due to climate change, habitat loss as well
as habitat degredation .
The species sampled appear to experience sympatry at multiple locations.
This indicates that the species may have an unknown ecological niche
separation or are syntopic in nature . Sympatry and syntopy are common
in in disttanly related mygalomorph spiders and has been reported
several times (Leavitt et al., 2015; Satler et al., 2011; Wilson et al.,
2018). But in this case, the lineages are not as distantly related,
posing the question of whether there is a possible niche divergence and
what this may be. In the genera Aliatypus (North America) andEuoplos (Australia) the niche divergence was observed in the
structure of the trapdoor lid and the habitat around the burrow (slopes
and leaf litter) (Satler et al., 2011; Wilson et al., 2017). The further
study of the species co-occuring at these localities and the habitats
may shed light on the speciation mechanisims within the genus.