Late Pleistocene pteropods, heteropods and planktonic foraminifera from the Caribbean Sea, Mediterranean Sea and Indian Ocean (original) (raw)
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Paleontological Journal, 2011
Evolutionary history of three mollusk classes (Bivalvia, Gastropoda, and Cephalopoda), regarded as components of the Phanerozoic marine biota, is discussed based on the comparison of dynamics of quantitative parameters obtained from the analysis of the global paleontological databases. The main trends in the evolution of the role of mollusks in Phanerozoic marine ecosystems and relationships between the diversification of this group and biodiversity of paleocommunities are considered. Certain parameters show similarity between the diversity dynamics of mollusks and the whole marine biota, including the paleolatitudinal distribution of diversity. At the same time, mollusk classes differ considerably in certain aspects. The evolutionary history of Bivalvia, Gastropoda, and Cephalopoda was different and determined presumably by deep ecological divergence which occurred as early as the Early Paleozoic adaptive radiation. Bivalves and gastropods followed the trend of a gradual and constant increase in their role in marine communities; they are characterized by high and constantly growing duration of genera, high (and also growing) frequency in paleontological collections. Cephalopods show more chaotic macroevolutionary dynamics, relatively low mean duration of genera and low relative frequency.
Fossil-calibrated molecular phylogeny of atlantid heteropods (Gastropoda, Pterotracheoidea)
Research Square (Research Square), 2020
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.
Journal of Earth System Science
Palaeobiogeographical distribution of gastropod genera from the Paleocene and the Eocene has been analysed. Based on this distribution, formal palaeobiogeographical provinces have been established and their relationships are sought. It has been found that the provinces were largely restricted to the palaeotropics and subtropics mainly of the northern hemisphere and they share a large proportion of their generic composition. The Northern Tropical Realm has been established to include these provinces. The distribution evinces presence of ocean surface currents in the tropics across longitudes. The possible currents moved through the relict Tethys Ocean, across the Atlantic Ocean and perhaps also across the Pacific. However, planktotrophic larvae of these benthic molluscs could not cross the deep ocean barrier that lay between the Northern Tropical Realm and the Austro-New Zealand Province of the southern hemisphere. The gastropod fauna in the latter province evolved independently. Distribution of all the provinces within palaeo-tropics and subtropics indicates strong control of temperature over it. Paleocene-Eocene Thermal Maximum appears to be responsible for extinction and range contraction of high latitude faunas. Low latitude faunas also suffered significant extinction. However, large diversification in the Eocene was a response to widespread transgression that coincided with the thermal event.
Proceedings of the Biological Society of Washington, 2013
Fossils of a single pteropod species were found in an isolated carbonate deposit within middle Eocene deep-water strata of the Humptulips Formation in western Washington State, U.S.A. The carbonate formed at a cold seep where fluids containing high concentrations of hydrocarbons, principally methane, emanated from the seafloor. Anaerobic oxidation of the methane by prokaryotes caused localized and rapid precipitation of calcium carbonate that encased biogenic detritus including wood fragments and mollusk shells; in this case even the minute and delicate aragonitic shells of the pteropod Heliconoides nitens (Lea, 1833), the first certain record of this taxon for the Pacific Basin. The presence of H. nitens in the Humptulips Formation allows us to recalibrate the age of the formation as late Lutetian or early Bartonian, up to 8 million years younger than previously thought. Heliconoides nitens has been found in temporally equivalent strata elsewhere in the world, and this is another example of some fossil pteropods having utility for long distance biostratigraphic correlations. Pteropod shells rapidly dissolve in deep-water environments, thus cold seep deposits may be a source of pteropod fossils in deep-water strata where they otherwise would not occur.
Six samples from two localities in Eocene deposits of central Uzbekistan yielded 14 species of holoplanktonic molluscs (1 Pterotracheoidea, 9 Limacinoidea, 3 Cavolinioidea and 1 Cymbulioidea). Limacina asiatica spec. nov. and L. dzheroiensis spec. nov. are introduced. The assemblages are interpreted as belonging to the later part of Pteropod Zone 9 (Ypresian, two samples) and the early part of Zone 10 (Ypresian-Lutetian, four samples) and correlated with the existing global nannoplankton zonation (zones NP 13 to lower NP 15).
Journal of Systematic Palaeontology, 2012
A new gastropod, Kaneconcha knorri gen et sp. nov., was found in marlstone dredged from the surface of Adam Dome at Kane Megamullion on the flank of the Mid-Atlantic Ridge in an area of former hydrothermal activity. The snail is interpreted as a large provannid similar to the chemosymbiotic genera Ifremeria and Alviniconcha. This is the first record of presumably chemosymbiotic provannids from the Atlantic Ocean and also the first fossil record of such large provannids associated with hydrothermal venting. Extant Alviniconcha and Ifremeria are endemic to hydrothermal vents in the Pacific and Indian oceans. Kaneconcha differs from Ifremeria in having no umbilicus and a posterior notch, and from Alviniconcha in having the profile of the whorl slightly flattened and having no callus on the inner lip. A dark layer covering the Kaneconcha shell is interpreted here as a fossilized periostracum. The shell/periostracum interface shows fungal traces attributed to the ichnospecies Saccomorpha clava. We hypothesize that large chemosymbiotic provannids (i.e. Kaneconcha, Ifremeria, and Alviniconcha) form a clade that possibly diverged from remaining provannids in the Late Jurassic, with the Late Jurassic/Early Cretaceous Paskentana being an early member.