Work

Traversing the North Pacific: Biogeography and connectivity patterns of deep-sea isopods across three trench systems

Year: 2025

Type: article

Abstract: • Genetic analyses revealed far larger isopod biodiversity in the deep North Pacific than initially assumed. • The presence of species complexes might represent a rule rather than an exception for deep-sea isopods. • Faunal overlap across vast distances and the North Pacific abyssal plains is confirmed in multiple species. • Isolation by Distance was detected in deep-sea isopods, likely driven by different life-history strategies. The vast extent of the deep-sea floor raises questions about the connectivity and extent of benthic biodiversity, while simultaneously rendering studies on biogeographic distribution patterns and population genetics difficult due to underexploration. This study investigates the biodiversity, connectivity and biogeography of janiroidean isopods from the relatively well-studied North Pacific (NP), a taxon often considered to mostly comprise poor dispersers. This contribution focuses on janiroidean species recorded from the NP abyssal plains interconnecting the regions surrounding the eastern Aleutian Trench (AT), the Kuril-Kamchatka Trench (KKT), and the Japan Trench (JT). It has the goal to investigate faunal connectivity and to infer potential influences of Isolation by Distance. The study is centered around the epibenthic Haploniscidae Hansen, 1916 and the endobenthic Macrostylidae Hansen, 1916 , analyzing their distributional ranges as well as molecular structuring and differentiation patterns using an extensive dataset of 16S rRNA sequences and COI barcodes. Species delimitation analyses revealed the existence of multiple new “cryptic” species amongst established taxa in both families, resulting in much more diverse biodiversity patterns across the whole NP than initially assumed based on morphology alone. While only a single macrostylid species showed a distribution spanning from the abyssal plains of the AT region to the ones of the JT/KKT regions, multiple haploniscid species reportedly possess ranges of several thousand kilometers across the abyssal plains of the NP. Isolation by Distance was inferred within most species appearing in at least two of the three greater trench regions investigated. These observed differences in biogeography and the inferred molecular variation patterns can be explained by different life-history strategies.

Source: Progress In Oceanography

DOI: 10.1016/j.pocean.2025.103623

Authors: Henry Knauber, Angelika Brandt, Torben Riehl

Institutions: Goethe University Frankfurt, Senckenberg Research Institute and Natural History Museum Frankfurt/M

Language: English

Topic: Marine Biology and Ecology Research

Subfield: Oceanography

Field: Earth and Planetary Sciences

Domain: Physical Sciences

SDG: Life below water

Open Access status: hybrid

Estimated APC paid: $3,720