Fossil-calibrated molecular phylogeny of atlantid heteropods (Gastropoda, Pterotracheoidea)

Abstract

Background The aragonite shelled, planktonic gastropod family Atlantidae (shelled heteropods) is likely to be one of the first groups to be impacted by imminent ocean changes, including ocean warming and ocean acidification. With a fossil record spanning at least 100 Ma, atlantids have experienced and survived global-scale ocean changes and extinction events in the past. However, the diversification patterns and tempo of evolution in this family are largely unknown. Results Based on a concatenated maximum likelihood phylogeny of three genes (cytochrome c oxidase subunit 1 mitochondrial DNA, 28S and 18S ribosomal rRNA) we show that the three extant genera of the family Atlantidae, Atlanta, Protatlanta and Oxygyrus, form monophyletic groups. The genus Atlanta is split into two groups, one exhibiting smaller, well ornamented shells, and the other having larger, less ornamented shells. The fossil record, in combination with a fossil-calibrated phylogeny, suggests that large scale atlantid extinction was accompanied by considerable and rapid diversification over the last 25 Ma, potentially driven by vicariance events. Conclusions Now confronted with a rapidly changing modern ocean, the ability of atlantids to survive past global change crises gives some optimism that they may be able to persist through the Anthropocene.

Toward a global reference database of COI barcodes for marine zooplankton

“…They are thus considered to be vulnerable to ocean acidification, but the deposition of their shells in marine sediments has also provided a unique and invaluable fossil record of the biodiversity of pelagic ecosystems. The fossil record makes these holoplanktonic gastropods particularly useful for studying evolutionary processes in metazoan plankton in the global ocean (Peijnenburg et al 2020;Wall-Palmer et al 2020).…”

A possible home for a bizarre Carboniferous animal: is Typhloesus a pelagic gastropod?

“…The five clades identified in the early Mesozoic have no obvious phylogenetic link to the younger heteropods that gave rise to the extant taxa [27]. The origins of the modern taxa date from the Cretaceous and occur in the form of the Atlantidae [28]. The more derived carinariids (and pterotracheiids) [29], to which Typhloesus might bear some closer comparison, only appeared in the Cainozoic.…”

The impacts of past, present and future ocean chemistry on predatory planktonic snails

“…Our results demonstrate that the effects of OA on atlantid calcification are not straight forward, and likely depend on whether these organisms are able to survive and maintain calcification under stressful conditions in the long term. Evidence suggests that both shelled pteropods and atlantids survived the Cretaceous-Paleogene extinction event (KPg or KT) and Paleocene-Eocene thermal maximum (PETM), both periods of extreme perturbation in the ocean's carbon cycle [38,39]. These findings give some hope that aragonite shelled holoplanktonic gastropods will be able to adapt to our changing oceans, even though the rate of change is unprecedented relative to the geological record.…”

“…Third, atlantids can have high abundances in cold, mid-high latitude regions that have a higher capacity to absorb atmospheric CO 2 , thus more rapidly becoming acidic compared to warmer regions [26,33]. Yet, despite the supposed vulnerability of aragonite shelled planktonic gastropods to OA, recent research suggests that atlantids and shelled pteropods survived past large-scale global change crises [38,39]. One of these events, the Paleocene-Eocene Thermal Maximum (PETM), is the most analogous geological event to the current Anthropogene climate crisis [40].…”