Pelagic Filters and Seafloor Anchors: A Hierarchical Model of Diversification in Benthopelagic Shrimps Pasiphaea
Alexander L. Vereshchaka, Anton M. Tikhomirov, Dmitry N. Kulagin, Anastasiia A. LuninaABSTRACT
Aim
To reconstruct the phylogeny of the genus Pasiphaea across the benthopelagic interface, a unique evolutionary frontier involving migrations between the seafloor and the water column, and to analyse the environmental variables associated with clade separation.
Location
Global deep‐sea ecosystems, encompassing both horizontal geographic distributions (latitudinal gradients) and vertical marine dimensions (pelagic water column and seafloor topography).
Time Period
Contemporary global distribution data.
Major Taxa Studied
Global fauna of the Glass shrimps Pasiphaea (Decapoda: Pasiphaeidae).
Methods
Reconstruction of a robust molecular phylogenetic dataset comprising 121 sequences from three genes, integrating available reliable data on the geographical and bathymetric distribution and phylogeny of Pasiphaea , followed by the evaluation of environmental variables associated with clade separation using various statistical models.
Results
Primary deep‐scale phylogenetic divergence was linked to pelagic environmental filtering, specifically latitude (as a proxy for temperature and productivity) and pelagic depth (nighttime habitat), which separated a high‐latitude, deep‐mesopelagic lineage (Clade A) from a lower‐latitude, shallower‐dwelling radiation (Clade B). In contrast, secondary diversification into terminal clades was associated with benthic factors, including seafloor geography (vicariance) and bottom depth (daytime habitat).
Main Conclusions
We propose a “dual‐link” hierarchical framework for benthopelagic evolution, showing that while pelagic factors explain the broad evolutionary trajectory and deep‐scale divergence of benthopelagic taxa, the seafloor provides the geographic anchors necessary for further terminal speciation. This underscores the critical importance of integrating both vertical and horizontal environmental dimensions to understand the complex mosaic of deep‐sea benthopelagic diversification.