Global biogeography and evolution of Cuvierina pteropods

Abstract

BackgroundShelled pteropods are planktonic gastropods that are potentially good indicators of the effects of ocean acidification. They also have high potential for the study of zooplankton evolution because they are metazoan plankton with a good fossil record. We investigated phenotypic and genetic variation in pteropods belonging to the genus Cuvierina in relation to their biogeographic distribution across the world’s oceans. We aimed to assess species boundaries and to reconstruct their evolutionary history.ResultsWe distinguished six morphotypes based on geometric morphometric analyses of shells from 926 museum and 113 fresh specimens. These morphotypes have distinct geographic distributions across the Atlantic, Pacific and Indian oceans, and belong to three major genetic clades based on COI and 28S DNA sequence data. Using a fossil-calibrated phylogeny, we estimated that these clades separated in the Late Oligocene and Early to Middle Miocene. We found evidence for ecological differentiation among all morphotypes based on ecological niche modelling with sea surface temperature, salinity and phytoplankton biomass as primary determinants. Across all analyses, we found highly congruent patterns of differentiation suggesting species level divergences between morphotypes. However, we also found distinct morphotypes (e.g. in the Atlantic Ocean) that were ecologically, but not genetically differentiated.ConclusionsGiven the distinct ecological and phenotypic specializations found among both described and undescribed Cuvierina taxa, they may not respond equally to future ocean changes and may not be equally sensitive to ocean acidification. Our findings support the view that ecological differentiation may be an important driving force in the speciation of zooplankton.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-015-0310-8) contains supplementary material, which is available to authorized users.

Comparative phylogeography of the ocean planet

“…Populations of these cosmopolitan species are subdivided in two ways concordant with the BGCP framework: (i) by continental land masses separating ocean basins, and (ii) by habitat discontinuities in the equatorial region between subtropical gyres in the northern and southern hemispheres (140)(141)(142). The few global-scale phylogeographic studies have been restricted to copepods, but evidence from a diversity of other taxa sampled at ocean basin scales indicate that lineages have diverged both in allopatry and sympatry at much smaller geographic distances than anticipated, with examples drawn from chaetognaths (143), euphausiids (144), and mollusks (145).…”

The Miocene “Pteropod event” in the SW part of the Central Paratethys (Medvednica Mt., northern Croatia)

“…Modern pteropods nowadays are widely used as first indicators of ocean acidification effects on marine communities, due to their aragonitic shell (e.g., Hunt et al 2010;Bednaršek et al 2012a;Burridge et al 2015). The process of ocean acidification (reducing pH value) and reduction with a lowering of the CaCO 3 saturation as a result affects marine organisms building their skeletons from aragonite, a more soluble form of CaCO 3 than calcite.…”

The status of Cuvierina spoeli Rampal, 2002 and Cuvieria oryza Benson, 1835 (Gastropoda, Pteropoda, Cuvierinidae)

“…In both of her papers (Rampal, 2002, p. 214;2017, p. 35) C. atlantica was mentioned as occurring mainly in the Atlantic Ocean, but also present in the Indo-Pacific area. Although van der Spoel (1970, p. 118) initially supposed it to be present also in the Indo-Pacific, van der Spoel (1976, p. 49) clearly restricted its occurrence to the Atlantic, which was acknowledged by Janssen (2005) and Burridge et al (2015Burridge et al ( , 2016.…”

“…For the latter group this was acknowledged by Burridge et al (2015Burridge et al ( , 2016 who by means of integrative characteristics of shell-morphology, biogeography and DNA sequencing indeed demonstrated a specific status of the (mainly) northern Pacific population so far included in C. pacifica, that was introduced as C. tsudai Burridge, Janssen & Peijnenburg, 2016. A lack of fresh specimens at the time prevented a similar evaluation of the two C. urceolaris populations.…”

“…Alice K. Burridge (pers. comm., February 2018) checked these two GenBank data against her own sequences (Burridge al., 2015) and could acknowledge these reidentifications.…”