Conclusion
Iceland’s marine environment is comparable to a “natural laboratory”
that has shaped species’ distribution depending on a variety of factors.Haploniscus bicuspis is an Icelandic example of a benthic
deep-sea species that was previously assumed to occur in all water
masses around Iceland, but we have now found that there are cryptic
species found within. Haplonicus bicuspis I-III is indicated as
the “true bicuspis ” North of Iceland. Whether species IV or V
corresponds to H. tepidus needs to be evaluated, and they require
a thorough redescription after the initial distinciton by Wolff (1962).
Speciation processes in these benthic deep-sea species were probably
driven by the interaction of geographic separation via the GIF Ridge
with the associated ecological differences and past climatic changes.
Genetic bottlenecks, potentially resulting from ice ages, were followed
by population expansions into previously glaciated regions. Migration is
male-biased, which results in hybrid zones and the complete exchange of
the local nuclear genome in a few instances. Population genetics
indicate mostly high levels of inbreeding and population
differentiation, despite such cases of extensive male-biased dispersal.
Such patterns may be typical for deep-sea benthic peracarid species,
which are a crucial component of the fauna.