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We provide preliminary insights into the global phylogeographic and
evolutionary patterns across species of the hydrozoan superfamily
Plumularioidea (Cnidaria: Hydrozoa). We analysed 1114 16S sequences of 198
putative species of Plumularioidea collected worldwide. We investigated
genetic connections and divergence in relation to present-day and ancient
biogeographic barriers, climate changes and oceanic circulation.
Geographical distributions of most species are generally more constrained
than previously assumed. Some species able to raft are dispersed widely.
Human-mediated dispersal explains some wide geographical ranges.
Trans-Atlantic genetic connections are presently unlikely for most of the
tropical-temperate species, but were probably more frequent until the
Miocene-Pliocene transition, before restriction of the Tethys Sea and the
Central American Seaway. Trans-Atlantic colonisations were predominantly
directed westwards through (sub)tropical waters. The Azores were colonized
multiple times and through different routes, mainly from the east
Atlantic, at least since the Pliocene. Extant geminate clades separated by
the Isthmus of Panama have predominantly Atlantic origin. Various ancient
colonisations mainly directed from the Indian Ocean to the Atlantic,
occurred through the Tethys Sea and around South Africa in periods of
lower intensity of the Benguela upwelling. Thermal tolerance, population
sizes, dispersal strategies, oceanic currents, substrate preference and
land barriers are important factors for dispersal and speciation of marine
hydroids.
143 views reported since publication in 2020.