Are Deep‐Pelagic Fishes Truly Circumglobal? Evolutionary and Biogeographic History of Sternoptyx and Argyropelecus (Stomiiformes: Sternoptychidae) Reveals E
Yan R. Kurtz, Gabriel S. Araujo, Allan P. B. Pozzobon, Pablo R. Gonçalves, Dahiana Arcila, Benjamin W. Frable, Leandro N. Eduardo, Arnaud Bertrand, Michael M. MincaroneABSTRACT
Aim
Deep‐pelagic fishes are often assumed to exhibit high connectivity and circumglobal distribution due to their usually large population sizes, pelagic lifestyle, and association with major oceanic current systems. However, recent molecular evidence challenges this paradigm, revealing geographically structured genetic diversity and cryptic lineages. Here, we investigate whether two widespread genera of deep‐pelagic hatchetfishes, Sternoptyx and Argyropelecus , conform to expectations of global connectivity or instead exhibit spatially structured evolutionary histories shaped by historical oceanographic barriers.
Location
Global.
Taxon
Deep‐pelagic hatchetfishes (Sternoptychidae: Sternoptyx , Argyropelecus ).
Methods
Using a global dataset of mitochondrial Cytochrome C Oxidase I sequences, we inferred time‐calibrated phylogenies, reconstructed haplotype networks, estimated genetic divergence, and applied lineage delimitation approaches to identify primary species hypotheses.
Results
Both genera exhibit pronounced geographic structuring, with multiple deeply divergent lineages corresponding to ocean basins and sub‐basin regions, indicating that several nominal species do not represent single, circumglobal evolutionary units. Divergence times cluster in the Miocene–Pliocene and coincide with major geological events that reorganised ocean circulation, including the constriction of the Indonesian Seaway, the shoaling of the Central American Seaway, and shifts in thermohaline circulation.
Main Conclusions
Despite their high dispersal potential, deep‐pelagic fishes can exhibit strong historical biogeographic structure, demonstrating that long‐term palaeoceanographic processes have been central in shaping diversification across the open ocean. Just as these forces have driven the cryptic divergence uncovered in Sternoptyx and Argyropelecus , it is likely that analogous palaeoceanographic drivers underlie unrecognised lineage structure in many other widely distributed deep‐pelagic taxa, urging a systematic reassessment of diversity, connectivity, and conservation status in the open ocean.