Geographic locations of presence points and the size of 14 skull measurements

The phylogeny and species boundaries of Gazella subgutturosa and G. marica
have been long debated. The achievements of past conservation efforts have
been compromised by a lack of knowledge about the phylogeny and taxonomic
status of different populations. We integrated the recent genetic findings
by previous studies with morphometric analyses and ecological niche
modelling (ENM) to assess discreteness among populations of these gazelle
species in Asia. Taxonomic diversity of gazelles was investigated by using
principal components analysis (PCA) based on 14 cranial measures of male
skulls. Ecological niche divergence was examined based on a PCA on
climatic factors and a species distribution modelling (SDM) with
environmental variables. Morphometric results indicated substantial
differentiation in size between skulls of the western Zagros Mountains
including west and south-western Iran and Arabian Peninsula from all other
samples east of the Zagros Mountains from Iran to China. ENM also revealed
that gazelles in the east and west of Zagros Mountains occupy distinct
niches and that there are apparent areas of disconnection across the
goitered gazelle suitable range. A complete divergent niche occupation was
also observed between gazelles of Mongolia and other Asiatic gazelles,
except for China. Taking the inferences from ENM and morphology together
with previous genetics results, we conclude that gazelles in the west and
southwest of Iran may represent G. marica. Also, our combined analyses
revealed divergence among gazelles of Iran, Central Asia, and
Mongolia/China. These results may pave the way for future studies and have
conservation implications particularly for reintroduction/supplementation
programs.