Hot off the press: biogeography of Southern Ocean sea stars

Our paper on the biogeography of Southern Ocean sea stars is out in Journal of Biogeography:

Reproductive strategy as a piece of the biogeographic puzzle: a case study using Antarctic sea stars (Echinodermata, Asteroidea), by Camille Moreau et al.

Aim: To describe and analyse asteroid biogeographic patterns in the Southern Ocean (SO) and test whether reproductive strategy (brooder versus broad- caster) can explain distribution patterns at the scale of the entire class. We hypothesize that brooding and broadcasting species display different biogeo- graphic patterns.

Location: Southern Ocean, south of 45 °S.

Methods: Over 14,000 asteroid occurrences are analysed using bootstrapped spanning network (BSN), non-metrical multidimensional scaling (nMDS) and clustering to uncover the spatial structure of faunal similarities among 25 bioregions.

Results: Main biogeographic patterns are congruent with previous works based on other taxa and highlight the isolation of New Zealand, the high richness in the Scotia Arc area particularly of brooding species, an East/West Antarctic dif- ferentiation, and the faunal affinities between South America and sub-Antarctic Islands. Asteroids show lower endemism levels than previously reported with 29% of species occurring in Antarctica only. In particular, asteroids from Tierra del Fuego showed affinities with those of West Antarctica at the species level, suggesting a recent mixing of assemblages. Biogeographic patterns are highly linked to reproductive strategy. Patterns also differ according to the tax- onomic level, revealing the underlying role of historical factors.

Main conclusions: Patterns of sea star biogeography are consistent with results obtained for other marine groups and are strongly linked to reproductive strategy.

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