Evolutionary Novelty and Atavism in the Semionotus Complex: Relaxed Selection During Colonization of an Expanding Lake

McCune, Amy R.

doi:10.2307/2409525

Cited by 22 publications

(11 citation statements)

References 23 publications

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“…In Great Britain it appears to occur at the top of the contorted interval interpreted as a seismite (Mayall 1983;Simms 2007), corresponding to the base of the 'initial' isotopic excursion of Hesselbo et al (2002) and within the 'dead zone' that marks the marine extinction level (Mander et al 2008 fig. Kozur & Weems (2007 also cite Bulbilimnadia sheni from the middle East Berlin Formation of the Hartford basin (Westfield Fish Bed), and the present authors have found this taxon in the exact homotaxial and time equivalent in the Newark basin, 'cycle P3' of McCune (1990) (Olsen 2010). 9) in the Newark basin, and in the Newark Supergroup in general, below the oldest basalt and above the E. olseni zone, and specifically between the grey shale marking the base of the Exeter Township Member of the Passaic Formation and the Orange Mountain Basalt, as discussed above.…”

Section: Conchostracan Biostratigraphysupporting

confidence: 51%

Implications of the Newark Supergroup-based astrochronology and geomagnetic polarity time scale (Newark-APTS) for the tempo and mode of the early diversification of the Dinosauria

Olsen

Kent

Whiteside

2010

Earth and Environmental Science Transactions of the Royal Socie

101

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2010). Implications of the Newark Supergroup-based astrochronology and geomagnetic polarity time scale (Newark-APTS) for the tempo and mode of the early diversication of ABSTRACT: The Newark-APTS established a high-resolution framework for the Late Triassic and Early Jurassic. Palaeomagnetic polarity correlations to marine sections show that stage-level correlations of continental sequences were off by as much as 10 million years. New U-Pb ages show the new correlations and the Newark basin astrochronology to be accurate. Correlation of Newark-APTS to the Chinle Formation/Dockum Group, Glen Canyon Group, Fleming Fjord Formation and Ischigualasto Formation led to the following conclusions: (1) there are no unequivocal Carnian-age dinosaurs; (2) the Norian Age was characterised by a slowly increasing saurischian diversity but no unequivocal ornithischians; (3) there was profound Norian and Rhaetian continental provinciality; (4) the classic Chinle-, Germanic-and Los Colorados-type assemblages may have persisted to the close of the Rhaetian; (5) the distinct genus-level biotic transition traditionally correlated with the marine Carnian-Norian is in fact mid-Norian in age and within published error of the Manicouagan impact; (6) the end-Triassic marine and continental extinctions as seen in eastern North America were contemporaneous; and (7) compared to Triassic communities, Hettangian and Sinemurian age terrestrial communities were nearly globally homogenous and of low diversity. Consequently, the complex emerging picture of dinosaur diversification demands biostratigraphically-independent geochronologies in each of the faunally-important regions.

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Section: Conchostracan Biostratigraphysupporting

confidence: 51%

Implications of the Newark Supergroup-based astrochronology and geomagnetic polarity time scale (Newark-APTS) for the tempo and mode of the early diversification of the Dinosauria

Olsen

Kent

Whiteside

2010

Earth and Environmental Science Transactions of the Royal Socie

101

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“…The accumulation of species−richness calcu− lated for Ceratites is an order of magnitude lower than exam− ples of species−flocks of fishes (Greenwood 1981;McCune 1990McCune , 1996 and Cretaceous ammonites (Yacobucci 1999), but the radiation of Ceratites remains an important case of a radiation within a restricted area in the fossil record.…”

Section: Discussionmentioning

confidence: 90%

“…The cichlid flocks of the African Rift Lakes (Meyer 1993) and the radia− tion of Geospiza (Darwin's finches) on the Galapagos Is− lands are two exemplars of geographically restricted radia− tions among living taxa. McCune (1990McCune ( , 1996 provided convincing evidence that such events can be detected in the fossil record as far back as the Triassic among Semionotus fish in rift−basins.…”

Section: Introductionmentioning

confidence: 92%

A quantitative null model of additive diversity partitioning: examining the response of beta diversity to extinction

Layou¹

2007

Paleobiology

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Paleobiological diversity is often expressed as α (within-sample), β (among-sample), and γ (total) diversities. However, when studying the effects of extinction on diversity patterns, only variations in α and γ diversities are typically addressed. A null model that examines changes in β diversity as a function of percent extinction is presented here.The model examines diversity in the context of a hierarchical sampling strategy that allows for the additive partitioning of γ diversity into mean α and β diversities at varying scales. Here, the sampling hierarchy has four levels: samples, beds, facies, and region; thus, there are four levels of α diversity (α1, α2, α3, α4) and three levels of β diversity (β1, β2, and β3). Taxa are randomly assigned to samples within the hierarchy according to probability of occurrence, and initial mean α and β values are calculated. A regional extinction is imposed, and the hierarchy is resampled from the remaining extant taxa. Post-extinction mean α and β values are then calculated.Both non-selective and selective extinctions with respect to taxon abundance yield decreases in α, β, and γ diversities. Non-selective extinction with respect to taxon abundance shows little effect on diversity partitioning except at the highest extinction magnitudes (above 75% extinction), where the contribution of α1 to total γ increases at the expense of β3, with β1 and β2 varying little with increasing extinction magnitude. The pre-extinction contribution of α1 to total diversity increases with increased probabilities of taxon occurrence and the number of shared taxa between facies. Both β1 and β2 contribute equally to total diversity at low occurrence probabilities, but β2 is negligible at high probabilities, because individual samples preserve all the taxonomic variation present within a facies. Selective extinction with respect to rare taxa indicates a constant increase in α1 and constant decrease in β3 with increasing extinction magnitudes, whereas selective extinction with respect to abundant taxa yields the opposite pattern of an initial decrease in α1 and increase in β3. Both β1 and β2 remain constant with increasing extinction for both cases of selectivity. By comparing diversity partitioning before and after an extinction event, it may be possible to determine whether the extinction was selective with respect to taxon abundances, and if so, whether that selectivity was against rare or abundant taxa.Field data were collected across a Late Ordovician regional extinction in the Nashville Dome of Tennessee, with sampling hierarchy similar to that of the model. These data agree with the abundant-selective model, showing declines in α, β, and γ diversities, and a decrease in α1 and increase in β3, which suggests this extinction may have targeted abundant taxa.

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“…"Pathomoplasy phylogenetically close to the or-tern" is meant in a statistical sense as a igin of major morphological innovations deviation from randomness in a way that (Riedl, 1978;Donoghue, 1989) or at the will be made precise below. The spatial patbase ofadaptive radiations (McCune, 1990). terns can assume many particular forms ( Fig.…”

mentioning

confidence: 99%

In Search of Homoplastic Tendencies: Statistical Inference of Topological Patterns in Homoplasy

Sanderson¹

1991

Evolution

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The "tendency" for homoplasy to appear in closely related taxa has been widely discussed but rarely quantified. This paper proposes statistical tests that examine the topological distribution of homoplasy within characters in phylogenies. They test whether character changes are localized (confined to some subtree), or clustered (occur in proximity to each other), relative to two null models of character evolution. Null Model I assumes that the observed number of character changes are dispersed randomly among the internodes of the tree, whereas Model II weights the probability that an internode contains a change by the length of that internodeestimated by the total number of character changes along that internode. Localization is measured by the largest furthest-neighbor distance between changes, clustering by the mean nearest neighbor distance. Distances are measured either by the number of intervening branches or the number of intervening character changes. Analyses of four cladistic data sets from the literature reveal very few characters that exhibit significant levels of clustering or localization-no more than would be expected by chance. In every data set a majority of characters exhibited at least weak tendencies, but in only one data set was there a significant excess of such characters. The present findings do not provide compelling evidence for the existence of "tendencies" in homoplasy, at least among characters used to reconstruct phylogenies. They should be sought elsewhere, in cladistic analyses oflarger scope, probably among a class of characters defined a priori on a structural or functional basis.

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Evolutionary Novelty and Atavism in the Semionotus Complex: Relaxed Selection During Colonization of an Expanding Lake

Cited by 22 publications

References 23 publications

Implications of the Newark Supergroup-based astrochronology and geomagnetic polarity time scale (Newark-APTS) for the tempo and mode of the early diversification of the Dinosauria

Implications of the Newark Supergroup-based astrochronology and geomagnetic polarity time scale (Newark-APTS) for the tempo and mode of the early diversification of the Dinosauria

A quantitative null model of additive diversity partitioning: examining the response of beta diversity to extinction

In Search of Homoplastic Tendencies: Statistical Inference of Topological Patterns in Homoplasy

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