Scientists from the Spanish Institute of Oceanography (IEO), in collaboration with the UAB, genetically analysed 1205 hake specimens from around the world. This allowed them to conclude that their common ancestors lived in the waters of Greenland some 50 million years ago.
Scientists from the Spanish Institute of Oceanography (IEO), in collaboration with the University of Vigo, the Universitat Autònoma de Barcelona, and the Institute of Marine Sciences of Barcelona (ICM-CSIC), genetically analysed 1205 hake specimens from around the world. This allowed them to reconstruct the evolutionary histroy of this fish species and suggest a hybrid origin of several rare morphotypes.
The world's oldest known hake fossils date back to the Middle Oligocene, some 30 million years ago, when ecosystems similar to the ones existing now began to form.
The genetic analyses reveal that the North American hake (Merluccius bilinearis) is the oldest of its genre. This is due to the fact that it most probably travelled from Greenland to the south, across a yet incipient Atlantic Ocean and then reached the Pacific.
The ancestral species of Merluccius split into two large groups: the Euro-African and the American groups, which formed as a result of the geological expansion of the Atlantic Ocean.
Posterior geological events, such as the closing of the maritime passage in Panama 3.5 million years ago, acted as a geographic barrier between the two lineages and favoured speciation.
This new research, published in Scientific Reports, suggests that there was a common origin for the 14 specimens representing nine morphotypes of rare hakes found in the southern Pacific and Atlantic oceans.
"Hybridation seems to be a recurrent topic in adjacent and superimposing regions, and this leads us to think that we may find more new rare morphotypes", explains Montse Pérez, researcher at the Oceanographic Centre in Vigo and lead autor of the paper. "We've reached a milestone with this information based on permanent museum samples, although there are still gaps in what we know about the hake's taxonomy", she concludes.
Reference:
Pérez, M., Fernández-Míguez, M., Matallanas, J. et al. Phylogenetic prospecting for cryptic species of the genus Merluccius (Actinopterygii: Merlucciidae). Sci Rep 11, 5929 (2021). https://doi.org/10.1038/s41598-021-85008-9
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Life below water
