Luca Schiavon, Valérie Dulière, Mario La Mesa, Ilaria AM Marino, Giuditta Codogno, Elisa Boscari, Emilio Riginella, Allessandra Battistotti, Magnus Lucassen, Lorenzo Zane, and Chiara Papetti (2021)
Species distribution, hybridization and connectivity in the genus Chionodraco: Unveiling unknown icefish diversity in antarctica
Diversity and Distributions.
Aim: The species of the genus Chionodraco (Notothenioidei) are the most abundant
icefish on the continental shelf of the Weddell Sea. While previous studies indicated
that only Chionodraco hamatus and Chionodraco myersi inhabit the Weddell Sea, the
third Chionodraco species, Chionodraco rastrospinosus, was recently sampled in the
area. As C. rastrospinosus is supposed to be found only at the Antarctic Peninsula and
Scotia Arc, this study aimed at confirming the species classification of C. rastrospinosus
by molecular methods and identifying its putative source population. Given the
documented evidence of introgression among the three species, we tested whether
the newly found C. rastrospinosus shared any genetic variability with the other
Chionodraco species. To explain the pattern of distribution of the Chionodraco species,
we aimed at estimating the hydrodynamic connectivity between the Antarctic
Peninsula and the Weddell Sea.
Location: Antarctic Peninsula, southern Scotia Arc and the south-eastern
Weddell
Sea.
Methods: We genotyped 19 microsatellites and sequenced the mitochondrial D-loop
for 560 Chionodraco individuals. We simulated the dispersal of more than 3 million
drifters (Lagrangian model).
Results: The molecular analyses support the presence of C. rastrospinosus in the
Weddell Sea and its homogeneity with C. rastrospinosus from the Antarctic Peninsula.
Bayesian clustering identifies three putative hybrids among C. rastrospinosus and the
other congenerics. Lagrangian simulations do not support connectivity driven by the
oceanographic features of the Antarctic Peninsula and Weddell Sea via passive larval
dispersal only.
Main conclusions: This study documents, for the first time, the presence of C. rastrospinosus
in the Weddell Sea unveiling more biodiversity than previously known in
this region. The sympatry of the three Chionodraco species explains the occurrence
of occasional, ongoing events of hybridization in the genus. Alternative possible
Peer Review, PDF available, Open Access, Impact Factor
- DOI: 10.1111/ddi.13249
Document Actions