The work is part of María Fernández’s doctoral thesis
The scientific journal Scientific Reports, belonging to the Nature group, collects the results of a study led by research staff from the Marine Genetic Resources Group (ReXenMar) of the Marine Research Center (CIM) of the University of Vigo and the AquaCOV group, from the Spanish Institute of Oceanography, which brings together the molecular proof of a common origin of all the rare morphotypes proposed as cryptic species of hake in the Southern Cone. The research was carried out between 2000 and 2020, through a worldwide sampling of valid hake species and nine morphotypes, in their distribution areas between the western South Atlantic, the eastern South Pacific and the western South Pacific.
The article, titled Phylogenetic prospecting for cryptic species of the genus Merluccius (Actinopterygii: Merlucciidae it is the result of the joint work of Montse Pérez, IEO scientist; Pablo Presa, researcher at the CIM; María Fernández Míguez, doctoral researcher at UVigo and taxonomist experts Jesús Matallanas, from the Zoology Unit of the Autonomous University of Barcelona, and Domingo Lloris, from the Institut de Ciències de él Mar (Cmima-CSIC) of Barcelona. Segundo explica o equipo, “as pescadas do xénero Merluccius inclúen 11 especies válidas, así como unha serie de morfotipos raros coñecidos como especies crípticas”. The researchers identified these morphotypes from the South Pacific and South Atlantic and assigned them to the phyloxene backbone of this genus. “This finding was possible thanks to the use of the phyloxenetic concatenation of sequences of nuclear genes such as ITS1-rDNA and mitochondrial genes such as Cytochrome b, together with the nested PCR design of rDNA”.
A natural phenomenon of hybridization
According to the authors of the work published by Scientific Reports, the article “shows that the multitude of morphotypes described in this genus is a natural phenomenon of hybridization between species with close genomes and overlapping ranges. Thus, this study has an important implication, since “it shows that said morphotypes cannot be claimed as potential representatives of fisheries news”.
Within the research results, the authors also indicate that “Bayesian analyzes indicated M. bilinearis and M. albidus as the oldest species of the genus and of the New World group, respectively. The phylogenetic situation of M. angustimanus from the upper part of the Gulf of California suggests its hybrid origin between M. gayi and M. productus is approximately 0.25 million years old, although a confinement of a subset of these species since then cannot be ruled out. ” In addition, they add, the results show “a common origin of all rare morphotypes and the absence of cryptic species of hake in the Southern Cone.” The molecular fingerprint of the morphotypes distributed between the southern western Pacific of New Zealand and the southern western Atlantic of Argentina is compatible with their respective hybrid origin between M. gayi and both, M. australis or M. hubbsi ”.
The article and the study that supports it are part of and give continuity to the line of work developed by the ReXenMar research group of the CIM, based in the Faculty of Biology, in collaboration with the AquaCOV group of the IEO. The work of this team from the University of Vigo is focused on research fields such as fisheries, forensic and aquaculture genetics. The conclusions collected in the article are part of the first chapter of María Fernández Míguez’s doctoral thesis, directed by researchers Pablo Presa (CIM) and Montse Pérez (IEO) and financed by the doctoral program of the Xunta de Galicia.
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