Journal Article
Evolution in the dark: Unexpected genetic diversity and morphological stasis in the blind, aquifer-dwelling catfish Horaglanis
Raghavan, R., Sundar, R.L., Arjun, C.P., Britz, R. and Dahanukar, N.
Record Number:
6066
Year:
2023
Journal:
Vertebrate Zoology
Pages:
57-74
Volume:
73
Notes:
Copyright Rajeev Raghavan et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use,
distribution, and reproduction in any medium, provided credit is given
Abstract:
The lateritic aquifers of the southern Indian state of Kerala harbour a unique assemblage of enigmatic stygobitic fishes which are
encountered very rarely, only when they surface during the digging and cleaning of homestead wells. Here, we focus on one of the
most unusual members of this group, the catfish Horaglanis, a genus of rarely-collected, tiny, blind, pigment less, and strictly aquifer-
residing species. A six-year exploratory and citizen-science backed survey supported by molecular phylogenetic analysis reveals
novel insights into the diversity, distribution and population structure of Horaglanis. The genus is characterized by high levels of
intraspecific and interspecific genetic divergence, with phylogenetically distinct species recovered above a 7.0% genetic-distance
threshold in the mitochondrial cytochrome oxidase subunit 1 gene. Contrasting with this deep genetic divergence, however, is a
remarkable stasis in external morphology. We identify and describe a new cryptic species, Horaglanis populi, a lineage that is the
sister group of all currently known species. All four species are represented by multiple haplotypes. Mismatch distribution reveals
that populations have not experienced recent expansions.
Times Cited:
4