Saha, A.; Chakraborty, S.; Ravikanth, G.; Praveen Karanth, K.; Aravind, N. (2022). Endemicity and radiation in waterfalls of the Western Ghats: The genus Cremnoconchus (Gastropoda: Littorinidae). Molecular Phylogenetics and Evolution. 174: 107547.
Endemicity and radiation in waterfalls of the Western Ghats: The genus <i>Cremnoconchus</i> (Gastropoda: Littorinidae)
Molecular Phylogenetics and Evolution
174: 107547
Publication
Snails of the genus Cremnoconchus – the only freshwater members of the gastropod family Littorinidae – are
endemic to the spray zones of numerous waterfalls in the Western Ghats of India. Cremnoconchus consists of nine
described and possibly numerous undescribed species as many of these appear to be restricted to specific waterfalls.
This is the first attempt at resolving the relationships between the various species in this genus and
establishing its monophyly in the family. Further, we also undertake species delimitation analysis to characterize
cryptic diversity in this group. Phylogenetic analyses based on nuclear and mitochondrial genes support the
monophyly of Cremnoconchus within the family. A fossil-calibrated Bayesian time tree suggests that this freshwater
lineage diverged from its marine counterparts around 90.40 million years ago. The separation of Cremnoconchus
from its marine ancestors might have been facilitated by the break-up of Gondwana or fluctuating sea
levels during this period. Species delimitation analysis retrieved 12 potentially undescribed species in this group.
These species formed two distinct clades in the phylogeny, one largely confined to the northern Western Ghats
and the other to the central Western Ghats. Species belonging to the northern and central Western Ghats seem to
have separated around 56.11 mya, i.e. after the northern Western Ghats were formed. Additionally, spatial
isolation due to the patchiness of suitable habitats (waterfalls) and low mobility might have facilitated their
diversification.