An ecologic model for test size variation in Recent planktonic foraminifera; applications to the fossil record

1976 ◽  
Vol 6 (4) ◽  
pp. 295-311 ◽  
Author(s):  
A. D. Hecht
Keyword(s):  
Fossil Record ◽  
Planktonic Foraminifera ◽  
Size Variation ◽  
Test Size ◽  
Ecologic Model

scholarly journals Evolution of body size in anteaters and sloths (Xenarthra, Pilosa): phylogeny, metabolism, diet and substrate preferences

2015 ◽  
Vol 106 (4) ◽  
pp. 289-301 ◽  
Author(s):  
N. Toledo ◽  
M.S. Bargo ◽  
S.F. Vizcaíno ◽  
G. De Iuliis ◽  
F. Pujos
Keyword(s):  
Body Size ◽  
Fossil Record ◽  
Dietary Habits ◽  
Decomposition Analysis ◽  
Size Variation ◽  
The Body ◽  
Phylogenetic Pattern ◽  
Substrate Preferences ◽  
Size Evolution ◽  
Main Factor

ABSTRACTPilosa include anteaters (Vermilingua) and sloths (Folivora). Modern tree sloths are represented by two genera, Bradypus and Choloepus (both around 4–6 kg), whereas the fossil record is very diverse, with approximately 90 genera ranging in age from the Oligocene to the early Holocene. Fossil sloths include four main clades, Megalonychidae, Megatheriidae, Nothrotheriidae, and Mylodontidae, ranging in size from tens of kilograms to several tons. Modern Vermilingua are represented by three genera, Cyclopes, Tamandua and Myrmecophaga, with a size range from 0.25 kg to about 30 kg, and their fossil record is scarce and fragmentary. The dependence of the body size on phylogenetic pattern of Pilosa is analysed here, according to current cladistic hypotheses. Orthonormal decomposition analysis and Abouheif C-mean were performed. Statistics were significantly different from the null-hypothesis, supporting the hypothesis that body size variation correlates with the phylogenetic pattern. Most of the correlation is concentrated within Vermilingua, and less within Mylodontidae, Megatheriidae, Nothrotheriidae and Megalonychidae. Influence of basal metabolic rate (BMR), dietary habits and substrate preference is discussed. In anteaters, specialised insectivory is proposed as the primary constraint on body size evolution. In the case of sloths, mylodontids, megatheriids and nothrotheriids show increasing body size through time; whereas megalonychids retain a wider diversity of sizes. Interplay between BMR and dietary habits appears to be the main factor in shaping evolution of sloth body size.

scholarly journals Diversity-dependence brings molecular phylogenies closer to agreement with the fossil record

2011 ◽  
Vol 279 (1732) ◽  
pp. 1300-1309 ◽  
Author(s):  
Rampal S. Etienne ◽  
Bart Haegeman ◽  
Tanja Stadler ◽  
Tracy Aze ◽  
Paul N. Pearson ◽  
...  
Keyword(s):  
Standard Model ◽  
Fossil Record ◽  
Evolutionary Dynamics ◽  
Planktonic Foraminifera ◽  
Fossil Evidence ◽  
Rate Of Increase ◽  
The Standard Model ◽  
Molecular Phylogenies ◽  
Biological Realism

The branching times of molecular phylogenies allow us to infer speciation and extinction dynamics even when fossils are absent. Troublingly, phylogenetic approaches usually return estimates of zero extinction, conflicting with fossil evidence. Phylogenies and fossils do agree, however, that there are often limits to diversity. Here, we present a general approach to evaluate the likelihood of a phylogeny under a model that accommodates diversity-dependence and extinction. We find, by likelihood maximization, that extinction is estimated most precisely if the rate of increase in the number of lineages in the phylogeny saturates towards the present or first decreases and then increases. We demonstrate the utility and limits of our approach by applying it to the phylogenies for two cases where a fossil record exists (Cetacea and Cenozoic macroperforate planktonic foraminifera) and to three radiations lacking fossil evidence ( Dendroica , Plethodon and Heliconius ). We propose that the diversity-dependence model with extinction be used as the standard model for macro-evolutionary dynamics because of its biological realism and flexibility.

scholarly journals Factors influencing test porosity in planktonic foraminifera

2018 ◽  
Vol 15 (21) ◽  
pp. 6607-6619 ◽  
Author(s):  
Janet E. Burke ◽  
Willem Renema ◽  
Michael J. Henehan ◽  
Leanne E. Elder ◽  
Catherine V. Davis ◽  
...  
Keyword(s):  
Fossil Record ◽  
Pore Space ◽  
Planktonic Foraminifera ◽  
Critical Role ◽  
Environmental Drivers ◽  
Geochemical Data ◽  
Test Surface ◽  
Metabolic Rates ◽  
Pore Characteristics ◽  
Test Volume

Abstract. The clustering of mitochondria near pores in the test walls of foraminifera suggests that these perforations play a critical role in metabolic gas exchange. As such, pore measurements could provide a novel means of tracking changes in metabolic rate in the fossil record. However, in planktonic foraminifera, variation in average pore area, density, and porosity (the total percentage of a test wall that is open pore space) have been variously attributed to environmental, biological, and taxonomic drivers, complicating such an interpretation. Here we examine the environmental, biological, and evolutionary determinants of pore characteristics in 718 individuals, representing 17 morphospecies of planktonic foraminifera from 6 core tops in the North Atlantic. Using random forest models, we find that porosity is primarily correlated to test surface area, test volume, and habitat temperature, key factors in determining metabolic rates. In order to test if this correlation arose spuriously through the association of cryptic species with distinct biomes, we cultured Globigerinoides ruber in three different temperature conditions, and found that porosity increased with temperature. Crucially, these results show that porosity can be plastic: changing in response to environmental drivers within the lifetime of an individual foraminifer. This demonstrates the potential of porosity as a proxy for foraminiferal metabolic rates, with significance for interpreting geochemical data and the physiology of foraminifera in non-analog environments. It also highlights the importance of phenotypic plasticity (i.e., ecophenotypy) in accounting for some aspects of morphological variation in the modern and fossil record.

scholarly journals Towards a morphological metric of assemblage dynamics in the fossil record: a test case using planktonic foraminifera

2016 ◽  
Vol 371 (1691) ◽  
pp. 20150227 ◽  
Author(s):  
Allison Y. Hsiang ◽  
Leanne E. Elder ◽  
Pincelli M. Hull
Keyword(s):  
Fossil Record ◽  
Phylogenetic Signal ◽  
Planktonic Foraminifera ◽  
Three Dimensional ◽  
Test Case ◽  
Ecological Traits ◽  
The North ◽  
Extant Species ◽  
The Relationship ◽  
Assemblage Size

With a glance, even the novice naturalist can tell you something about the ecology of a given ecosystem. This is because the morphology of individuals reflects their evolutionary history and ecology, and imparts a distinct ‘look’ to communities—making it possible to immediately discern between deserts and forests, or coral reefs and abyssal plains. Once quantified, morphology can provide a common metric for characterizing communities across space and time and, if measured rapidly, serve as a powerful tool for quantifying biotic dynamics. Here, we present and test a new high-throughput approach for analysing community shape in the fossil record using semi-three-dimensional (3D) morphometrics from vertically stacked images (light microscopic or photogrammetric). We assess the potential informativeness of community morphology in a first analysis of the relationship between 3D morphology, ecology and phylogeny in 16 extant species of planktonic foraminifera—an abundant group in the marine fossil record—and in a preliminary comparison of four assemblages from the North Atlantic. In the species examined, phylogenetic relatedness was most closely correlated with ecology, with all three ecological traits examined (depth habitat, symbiont ecology and biogeography) showing significant phylogenetic signal. By contrast, morphological trees (based on 3D shape similarity) were relatively distantly related to both ecology and phylogeny. Although improvements are needed to realize the full utility of community morphometrics, our approach already provides robust volumetric measurements of assemblage size, a key ecological characteristic.

scholarly journals New evidence on the origin of non-spinose pitted–cancellate species of the early Danian planktonic foraminifera

2013 ◽  
Vol 64 (3) ◽  
pp. 237-251 ◽  
Author(s):  
Ignacio Arenillas ◽  
Jose Antonio Arz
Keyword(s):  
Morphological Evolution ◽  
Planktonic Foraminifera ◽  
Middle Part ◽  
External Morphology ◽  
Evolutionary Trends ◽  
Test Size ◽  
Evolutionary Path ◽  
Origin And Evolution ◽  
Large Pore ◽  
New Evidence

Abstract Intermediate forms identified in some of the most continuous lower Danian sections allow a better understanding of the origin and evolution of pitted (Globanomalina) and cancellate (Praemurica) planktonic foraminifera. Both Globanomalina and Praemurica are part of a major Paleocene lineage, namely the “non-spinose lineage”, which started to diverge in the early Danian. Transitional specimens strongly suggest the evolution from Parvularugoglobigerina to Globanomalina, and then to Praemurica. These evolutionary turnovers were quite rapid (probably lasting less than 10 kyr), and seem to have begun in the time equivalent of the lower part of the E. simplicissima Subzone, namely the middle part of the standard Zone Pa. The initial evolutionary trends within this non-spinose lineage were the increase of test size and lip thickness, and the evolution from tiny pore-murals to large pore-pits, and from smooth to pitted and finally cancellate walls. Biostratigraphic data suggest that evolution of the wall texture preceded the morphological evolution within each genus. The oldest species of both Globanomalina and Praemurica, namely G. archeocompressa and Pr. taurica, initially retained the external morphology of the ancestral Parvularugoglobigerina eugubina. Since their divergence, Globanomalina and Praemurica followed a separate evolutionary path, evolving into morphologically different species.

scholarly journals Test-Size Evolution of the planktonic Foraminifera <i>Globorotalia menardii</i> in the Eastern Tropical Atlantic since the Late Miocene

2021 ◽  
Author(s):  
Thore Friesenhagen
Keyword(s):  
Atlantic Ocean ◽  
Planktonic Foraminifera ◽  
Early Pleistocene ◽  
Tropical Atlantic ◽  
Test Size ◽  
Tropical Atlantic Ocean ◽  
Size Evolution ◽  
Evolutionary Event ◽  
The Indian Ocean ◽  
Coiling Direction

Abstract. The mean test size of planktonic foraminifera (PF) is known to have increased especially during the last 12 Ma, probably in terms of an adaptive response to an intensification of the surface-water stratification. On geologically short timescales, the test size in PF is related to environmental conditions. In an optimal species-specific environment, individuals exhibit a greater maximum and average test size, while the size decreases the more unfavourable the environment becomes. An interesting case was observed in the late Neogene and Quaternary size evolution of Globorotalia menardii, which seems to be too extreme to be only explained by changes in environmental conditions. In the western tropical Atlantic Ocean (WTAO) and the Caribbean Sea, the test size more than doubles from 2.6 Ma to 1.95 Ma and 1.7 Ma, respectively, following an almost uninterrupted and successive phase of test size decrease from 4 Ma. Two hypotheses have been suggested to explain the sudden occurrence of a giant G. menardii form: it was triggered by either (1) a punctuated, regional evolutionary event or (2) the immigration of specimens from the Indian Ocean via the Agulhas Leakage. Morphometric measurements of tests from sediment samples of the Ocean Drilling Program (ODP) Leg 108 Hole 667A in the eastern tropical Atlantic Ocean (ETAO), show that the giant type already appears 0.1 Ma earlier at this location than in the WTAO, which indicates that the extreme size increase in the early Pleistocene was a tropical-Atlantic-Ocean-wide event. A coinciding change in the predominant coiling direction suggests that probably a new morphotype occurred. If the giant size and the uniform change in the predominant coiling direction are an indicator for this new type, the form already occurred in the eastern tropical Pacific Ocean at the Pliocene/Pleistocene boundary at 2.58 Ma. This finding supports the Agulhas Leakage hypothesis. However, the hypothesis of a regional, punctuated evolutionary event cannot be dismissed due to missing data from the Indian Ocean. This paper presents the AMOC/thermocline hypothesis, which not only suggests an alternative explanation for the sudden test-size increase in the early Pleistocene, but also for the test size evolution within the whole tropical Atlantic Ocean and the Caribbean Sea for the last 8 Ma. The test-size evolution shows a similar trend with indicators for changes in the Atlantic Meridional Overturning Circulation (AMOC) strength. The mechanism behind that might be that changes in the AMOC strength have a major influence on the thermal stratification of the upper water column, which is known to be the habitat of G. menardii.

Stratification and Oxygen Isotopes in the Paleozoic: Is Paleotermometry in Hot Water?

1998 ◽  
Vol 4 ◽  
pp. 244-254 ◽  
Author(s):  
Peter A. Allison ◽  
Rupert Ford ◽  
Richard Corfield
Keyword(s):  
Oxygen Isotopes ◽  
Fossil Record ◽  
Empirical Studies ◽  
Planktonic Foraminifera ◽  
Hot Water ◽  
Glacial Ice ◽  
Deep Waters ◽  
Isotope Method ◽  
Temperature Component ◽  
The Relationship

The oxygen isotope method is probably the most widely used proxy of paleotemperature determination in the fossil record. The relationship as first proposed by Urey (1947) suggests that the ratio of 18O to 16O in the calcitic shells of fossils is proportional to temperature. This was subsequently confirmed by empirical studies (Epstein et al, 1951, Emiliani, 1954; 1955). However, Shackleton (1967), suggested on the basis of co-variance of benthonic and planktonic foraminifera, that the δ18O composition of seawater varied only as a function of glacial ice growth and decay. However, more recent studies have shown that there is still a residual temperature component in the δ18O variability of deep waters.

Evolution Caught in the Act: Evidence from Microfossil Morphology

2002 ◽  
Vol 11 ◽  
pp. 127-138
Author(s):  
Stephen J. Culver
Keyword(s):  
Deep Sea ◽  
Fossil Record ◽  
Evolutionary History ◽  
Planktonic Foraminifera ◽  
Extensive Study ◽  
Calcareous Nannoplankton ◽  
Great Abundance ◽  
Morphologic Evolution ◽  
The Subject ◽  
Hand Sample

Microfossils are of prime importance in documenting patterns of evolution due to their great abundance (often tens of thousands to millions of specimens in a hand sample) and widespread distribution (in both time and space) in the fossil record. The term “microfossil” is often used for paleontological material that requires a microscope for its study, no matter what its biological affinities. For the purposes of this article we will be looking at the remains of protists (single-celled organisms). The several examples I discuss in this chapter are of three groups of planktonic (floating) protists: the calcareous nannoplankton (tiny plant-like protists whose single cell is covered in minute calcitic scales), the radiolaria (animal-like protists with siliceous shells), and the planktonic foraminifera (animal-like protists with calcitic shells). These organisms have been the subject of extensive study because the material from which they are often extracted, cores of deep-sea sediments, are usually comprised of a more complete sedimentological record (i.e., have fewer breaks) than shallow shelf deposits. Hypotheses of evolutionary history have been constructed for many groups (lineages) of microfossils using specimens from deep-sea cores. Ancestor-descendent relationships have been recognized by tracking shape and form (morphologic) changes through time. This approach to reconstruction of evolutionary history provides an empirical record of morphologic evolution; that is, a record based on observations.

Evolutionary ecology of Early Paleocene planktonic foraminifera: size, depth habitat and symbiosis

Paleobiology ◽  
2012 ◽  
Vol 38 (3) ◽  
pp. 374-390 ◽  
Author(s):  
Heather S. Birch ◽  
Helen K. Coxall ◽  
Paul N. Pearson
Keyword(s):  
Evolutionary Ecology ◽  
Dissolved Inorganic Carbon ◽  
Planktonic Foraminifera ◽  
Deep Ocean ◽  
Test Size ◽  
Early Paleocene ◽  
Ocean Carbon ◽  
Reconstructed Surface ◽  
Mass Extinction Event ◽  
The Impact

The carbon stable isotope (δ13C) composition of the calcitic tests of planktonic foraminifera has an important role as a geochemical tracer of ocean carbon system changes associated with the Cretaceous/Paleogene (K/Pg) mass extinction event and its aftermath. Questions remain, however, about the extent of δ13C isotopic disequilibrium effects and the impact of depth habitat evolution on test calcite δ13C among rapidly evolving Paleocene species, and the influence this has on reconstructed surface-to-deep ocean dissolved inorganic carbon (DIC) gradients. A synthesis of new and existing multispecies data, on the relationship between δ13C and δ18O and test size, sheds light on these issues. Results suggest that early Paleocene species quickly radiated into a range of depths habitats in a thermally stratified water column. Negative δ18O gradients with increasing test size in some species ofPraemuricasuggest either ontogenetic or ecotypic dependence on calcification temperature that may reflect depth/light controlled variability in symbiont photosynthetic activity. The pattern of positive δ13C test-size correlations allows us to (1) identify metabolic disequilibrium δ13C effects in small foraminifera tests, as occur in the immediate aftermath of the K/Pg event, (2) constrain the timing of evolution of foraminiferal photosymbiosis to 63.5 Ma, ∼0.9 Myr earlier than previously suggested, and (3) identify the apparent loss of symbiosis in a late-ranging morphotype ofPraemurica. These findings have implications for interpreting δ13C DIC gradients at a resolution appropriate for incoming highly resolved K/Pg core records.

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