bluuebunny/crossref_metadata_2025 huggingface dataset:
A 40,000-year record of discontinuous evolution of island snails
Authors: Chiba Satoshi
Published: July 2016

The rate and pattern of phenotypic evolution of the endemic land-snailMandarina chichijimanain the oceanic Bonin Islands through 40,000 years were examined by using radiocarbon-dated fossil specimens. There are drastic variations in rates and patterns of changes detected. Some characters show irregular fluctuation within a restricted range. Other characters show a rapid shift from stasis in one state to stasis in an alternative state. Because of the isolation, the limited distributions, and the presence of transitional forms, these changes are regarded as genuine evolutionary transformations within a lineage. These findings suggest that phyletic evolution is essentially irregular and punctuated.
Evolution of ammonoid morphospace during the Early Jurassic radiation
Authors: Dommergues Jean-Louis , Laurin Bernard , Meister Christian
Published: July 2016

The morphologic radiation of Early Jurassic ammonites following the near extinction at the end of the Triassic is analyzed from 436 species of 156 genera that form a representative sample of morphs occurring worldwide in the first three stages of the Jurassic (Hettangian, Sinemurian, Pliensbachian: 36 subzones, 24 m.y.). Morphologic diversity is analyzed independently of taxonomy by processing 18 shape parameters using multivariate analysis and clustering techniques. The morphospace thus defined indicates that morphs fall readily into two groups made up of four and five adjacent morpho-subsets. The temporal pattern of morphospace occupation in the 36 Lower Jurassic subzones displays diversification, depletion (sometimes total), and displacement of successive parts of the morphospace, reflecting a complex history in which morphologic radiation appears to be more than a process of diffusion. The history of the morphologic evolution is tentatively related to sea-level changes and there is a suggestion that morphologic diversity increases during second-order transgressive periods.
Heterochrony and heterotopy: stability and innovation in the evolution of form
Authors: Zelditch Miriam L. , Fink William L.
Published: July 2016

Heterochrony, change in developmental rate and timing, is widely recognized as an agent of evolutionary change. Heterotopy, evolutionary change in spatial patterning of development, is less widely known or understood. Although Haeckel coined the term as a complement to heterochrony in 1866, few studies have detected heterotopy or even considered the possibility that it might play a role in morphological evolution. We here review the roles of heterochrony and heterotopy in evolution and discuss how they can be detected. Heterochrony is of interest in part because it can produce novelties constrained along ancestral ontogenies, and hence result in parallelism between ontogeny and phylogeny. Heterotopy can produce new morphologies along trajectories different from those that generated the forms of ancestors. We argue that the study of heterochrony has been bound to an analytical formalism that virtually precludes the recognition of heterotopy, so we provide a new framework for the construction of ontogenetic trajectories and illustrate their analysis in a phylogenetic context. The study of development of form needs tools that capture not only rates of development but the space in which the changes are manifest. The framework outlined here provides tools applicable to both. When appropriate tools are used and the necessary steps are taken, a more comprehensive interpretation of evolutionary change in development becomes possible. We suspect that there will be very few cases of change solely in developmental rate and timing or change solely in spatial patterning; most ontogenies evolve by changes of spatiotemporal pattern.
What is gradualism? Cryptic speciation in globorotaliid foraminifera
Authors: Norris Richard D. , Corfield Richard M. , Cartlidge Julie
Published: July 2016

Analysis of the evolution of theGloborotalia(Fohsella) lineage of planktic foraminifera suggests that reproductive ecology and shell shape have evolved independently in this group. The silhouette of fohsellid shells displays a nearly unbroken anagenetic trend, yet isotopic data show that the fohsellids changed their depth of reproduction during the anagenetic evolution of their skeletons. Remarkably, there are no correlations between anagenesis in skeletal shape and the establishment of reproductive isolation. Apparently, anagenesis masks at least one speciation event that is apparent only in the isotopic evidence for a change in reproductive ecology. Although anagenetic trends have been widely cited as evidence for gradual speciation in planktic foraminifera and other microfossil groups, our data suggest that they should not always be considered to record either the tempo or mode of speciation.

Speciation was apparently uncoupled from morphological evolution in fohsellids because these evolutionary phenomena occurred in different phases of ontogeny. Gradual morphological changes were associated with the main phase of shell growth of both the ancestor and descendant species in the near-surface ocean. Reproductive isolation occurred when ancestral and descendant populations became established at different depths near the end of the life cycle. Morphological evolution may also be uncoupled from reproductive isolation in other organisms that experience very different selection pressures over the duration of their ontogenies, such as parasites with many hosts, species with multiple phases of metamorphosis, and organisms that broadcast their gametes.
Tests and confidence intervals for a common upper endpoint in fossil taxa
Authors: Solow Andrew R.
Published: July 2016

Statistical inference about the upper and lower endpoints of the stratigraphic ranges of fossil taxa can be based on the pattern of finds. Strauss and Sadler (1989) described a test and confidence interval for a common upper or lower endpoint in two or more taxa. This approach is conservative, in the sense that it provides only an upper bound on the significance level. This paper describes and illustrates a test and confidence interval for which the significance level is known.
Symbiosis as an evolutionary innovation in the radiation of Paleocene planktic foraminifera
Authors: Norris Richard D.
Published: July 2016

Symbioses are often regarded as an important means for the creation of evolutionary novelty as well as a trigger for the abrupt appearance of higher taxa. The fossil record of foraminifer-algal symbiosis suggests that the appearance of this ecological association contributed to the radiation of Paleogene planktic foraminifera. Isotopic evidence shows that photosymbiosis evolved in synchrony with a major diversification of trochospiral planktic foraminifera about 3.5 m.y. after the end-Cretaceous extinction. In modern planktic foraminifera, photosymbiotic species tend to have more cosmopolitan distributions than asymbiotic foraminifera and a greater ability to withstand periods of nutrient stress. The simultaneous taxonomic radiation and acquisition of photosymbiosis are evidence that the ecological strategy permitted Paleocene foraminifera to expand their niche in pelagic environments by diversifying into low-nutrient surface waters.

A comparison of the species longevities of Neogene and Paleogene symbiotic clades suggests that photosymbiosis does not regulate the characteristic rate of taxonomic turnover in clades after they appear. Species longevities are much shorter in Paleocene and Eocene photosymbiotic morphospecies than they are among photosymbiotic Neogene clades; apparently photosymbiosis does not exert a significant control over long-term evolutionary rates. In addition, the absence of a characteristic morphology associated with photosymbiosis in Cenozoic planktic foraminifera suggests that morphology, as with rate of evolutionary turnover, is linked to symbiosis only because of common inheritance instead of a functional relationship. Although the coincidence between the acquisition of photosymbiosis and generic diversification does suggest a linkage between this ecology and the appearance of foraminiferal higher taxa, there is little indication at the present that symbioses control long-term morphological or ecological patterns within these groups after their appearance. Photosymbiosis, and other evolutionary innovations, may be more a catalyst for the differentiation of major groups than a predictable governor on evolutionary rates.
Heterochrony in brontothere horn evolution: allometric interpretations and the effect of life history scaling
Authors: Bales Gerald S.
Published: July 2016

The Brontotheriidae (Perissodactyla, Mammalia) are often used as an illustration of vertebrate macroevolutionary trends because their morphological evolution includes significant size increases accompanied by the disproportionate lengthening of bony frontonasal horns. The positive phylogenetic allometry for horn length vs. skull length is among the strongest known of such relationships in vertebrate phylogeny. Hypotheses explaining the change from small, incipient horns in Eocene ancestors to longer horns in Oligocene descendants have included two heterochronic mechanisms, hypermorphosis (extrapolation) and predisplacement (earlier onset time of horn growth). These proposed peramorphic mechanisms derive from interpretation of adult intergeneric allometries in logarithmic data spaces. Analysis of the raw (unlogged) data shows that the simple allometric model previously used is not an appropriate model for this specific problem. The heterochronic interpretations derived from them are therefore unsupported (but not disproven) by the allometries. A more appropriate allometric model for the data (full model) does not support any heterochronic interpretation. Previously unaccounted for in the heterochronic hypotheses is a complication due to body-size scaling effects on life history stage lengths. Neontological scaling patterns suggest that brontothere size increases were probably accompanied by increasing life spans and longer developmental stages. This effect broadens the types of heterochronies that may be postulated. Semiquantitative analyses comparing brontotheres with similarly sized extant ungulates show the hypothesized effect of larger size on brontothere life history stages. A scaled descendant ontogeny introduces the problem of relative vs. absolute time frames within which to view ontogenetic onset times. Thus, predisplacements, postdisplacements, or nondisplacements may be viewed as relative or absolute with respect to ancestral ontogenies. This raises a fundamental question about how development scales, which in turn affects how heterochronies are interpreted. A scaling effect suggests that brontothere horns are more likely postdisplaced in the traditional absolute time sense. Paradoxically then, while the descendant adult horn is peramorphic, its onset time may have shifted in a paedomorphic direction. Data for two Oligocene juvenile brontotheres suggest that most horn growth occurred late in their longer (i.e., descendant) ontogenies (hypermorphosis), and that the horns probably grew at faster rates (acceleration) than in Eocene taxa.
Seven centuries of taphonomic variation in Eocene freshwater fishes preserved in varves: paleoenvironments and temporal averaging
Authors: Wilson Mark V. H. , Barton Douglas G.
Published: July 2016

Eocene lake beds of Horsefly, British Columbia, are preserved in varves, or discrete yearly layers representing seasonal changes in the lake. These varves allow study of temporal variation and rates of change in morphological and ecological characters on a very short time scale. One of the most sensitive indicators of the paleoenvironmental conditions on the floor of the lake may be the taphonomic condition of the fishes, which vary between perfectly articulated and completely disarticulated skeletons. Patterns of disarticulation correspond to those produced by scavengers. The taphonomy supports the hypothesis that the lake was warm monomictic, circulating in the winter, at which time scavengers could gain access to the bottom of the lake. Larger-scale environmental events (on the order of hundreds of years) are suggested by the fact that the proportion of well-preserved specimens reached two peaks within the seven centuries of deposition, one peak during the second century and another during the fifth and sixth centuries. These results clearly demonstrate two principles: that taphonomy can be a sensitive indicator of paleoenvironmental conditions, and that temporal averaging can affect the taphonomic properties of this fossil site, and presumably of others with equal or lower time resolution.
Cryptic speciation in the living planktonic foraminiferGlobigerinella siphonifera(d'Orbigny)
Authors: Huber Brian T. , Bijma Jelle , Darling Kate
Published: July 2016

Two living forms ofGlobigerinella siphonifera(d'Orbigny), presently identified as Type I and Type II, can easily be distinguished and collected by SCUBA divers because of differences in appearance, arrangement of the rhizopodial network, and the presence or absence of commensals. Additional biological differences are apparent from laboratory culture experiments; Type I individuals survive significantly longer than Type II under conditions of darkness and starvation and have significantly slower chamber formation rates. Stable isotopic analyses of Types I and II also reveal notable differences, with Type I consistently yielding more negative δ18O and δ13C values. Results of Mg/Ca ratio analyses indicate that Type II specimens precipitated their shells in slightly cooler (deeper) surface waters than Type I specimens. These observations and results from DNA sequencing unequivocally demonstrate thatG. siphoniferaTypes I and II should be regarded as biological sister species.

Contrarily, biometric analysis of the empty shells reveals few significant differences betweenG. siphoniferaTypes I and II. Of all the features measured from X-ray and SEM images of serially dissected specimens, only shell porosity yields readily discernible differences, with Type I adult chambers averaging 10–20% porosity and Type II adult chambers averaging 4–7% porosity. Statistically significant differences between Type I and II populations are revealed in maximum test diameter (Type I is typically larger) and coiling (Type I is typically more evolute), but these differences do not justify species level distinction of Types I and II using traditional paleontological species concepts.

On the basis of the above evidence, and since all specimens were collected at the same location at ∼3–8 m water depth, we conclude thatG. siphoniferaTypes I and II are living examples of cryptic speciation, whereby biological speciation has occurred in the absence of discernable change in shell morphology. However, it is not clear when or where this speciation took place. Preliminary study of deep-sea cores from the Caribbean and Pacific sides of the Isthmus of Panama reveals a predominance of specimens with Type II porosity values, with rare occurrence of specimens yielding Type I porosity values. Systematic downcore measurement of shell porosity and tightness of coiling needs to be extended back to the middle Miocene, whenG. siphoniferafirst appeared, to determine the timing of the Type I and II morphological divergence.

Postulated mechanisms for reproductive isolation and speciation of Types I and II include alloparapatric, depth parapatric, and sympatric speciation. These models could be tested if further analysis of fossilG. siphoniferashells allows determination of the timing of speciation, the preferred depth distribution, and the history of geographic distribution of Types I and II.
Maximum likelihood estimation of phylogeny using stratigraphic data
Authors: Huelsenbeck John P. , Rannala Bruce
Published: July 2016

The stratigraphic distribution of fossil species contains potential information about phylogeny because some phylogenetic trees are more consistent with the distribution of fossils in the rock record than others. A maximum likelihood estimator of phylogeny is derived using an explicit mathematical model of fossil preservation. The method assumes that fossil preservations within lineages follow an independent Poisson process, but can be extended to include other preservation models. The performance of the method was examined using Monte Carlo simulation. The performance of the maximum likelihood estimator of topology increases with an increase in the preservation rate. The method is biased, like other methods of phylogeny estimation, when the rate of fossil preservation is low; estimated trees tend to be more asymmetrical than the true tree. The method appears to perform well as a tree rooting criterion even when preservation rates are low. We suggest several possible extensions of the method to address other questions about the nature of fossil preservation and the process of speciation and extinction over time and space.
Reconstruction of TertiaryMetasequoiaforests. II. Structure, biomass, and productivity of Eocene floodplain forests in the Canadian Arctic
Authors: Williams Christopher J. , Johnson Arthur H. , LePage Ben A. , Vann David R. , Sweda Tatsuo
Published: July 2016

Abundant fossil plant remains are preserved in the high-latitude middle Eocene deposits of the Buchanan Lake Formation on Axel Heiberg Island, Nunavut Territory, Canada. Intact leaf litter, logs, and stumps preserved in situ as mummified remains offer an opportunity to determine the structure, biomass, and productivity of two Taxodiaceae-dominated forests that grew north of the Arctic Circle (paleolatitude 75–80°N). We excavated fossil tree trunks and treetops to develop equations that describe the height, structure, and mass of the aboveground components of Eocene-ageMetasequoiatrees. We combined those data with surveys of in situ stumps to determine the structure, biomass, and productivity of two fossil forests, “N” and “HR.” We calculated a canopy height of 40 ± 3 m for the N forest and 25 m ± 2 m for the HR forest. Buried knots in dissected logs and abundant branch-free bole wood indicate that these were tall, closed-canopy forests. Stem tapers indicate that the overstory was of uniform height. Stem volume equaled 2095 m3ha−1and stem biomass was 628 Mg ha−1in the N forest. Volume and biomass in the HR forest were much smaller, 211 m3ha−1and 63.3 Mg ha−1, respectively. We estimated understory tree biomass to be 40 Mg ha−1in the N forest and 3.5 Mg ha−1in the HR forest. Recovery of seven fossil treetops with exposed branch stubs enabled us to make estimates of branchwood and foliar biomass using allometric equations derived from modern, plantation-grownMetasequoia glyptostroboides. Estimated stand-level branch biomass was 13 and 6.7 Mg ha−1in the N and HR forests, respectively. Standing foliar biomass was estimated to be 3.2 and 2.1 Mg ha−1in the N and HR forests, respectively. Using annual ring widths, the reconstructed parabolic stems, and wood density of modernMetasequoia, we calculated annual wood production to be 2.3 Mg ha−1yr−1for the N forest and 0.55 Mg ha−1yr−1for the HR forest Assuming that the ancientMetasequoiawere deciduous like their living relatives, annual aboveground net primary productivity was 5.5 Mg ha−1yr−1for the N forest and 2.8 Mg ha−1yr−1for the HR forest. Our estimated biomass and productivity values for N are similar to those of modern old-growth forests of the Pacific Northwest of the United States and old-growth coastal Cordillera forests of southern Chile.
Evolution of shell morphology and suture complexity in Paleozoic prolecanitids, the rootstock of Mesozoic ammonoids
Authors: Saunders W. Bruce , Work David M.
Published: July 2016

The ammonoid order Prolecanitida constitutes a relatively small (43 genera, ~250 species) but long-ranging lineage (Lower Carboniferous—Triassic, ~108 m.y.), which narrowly survived the P/Tr extinctions and provided the stock from which were derived all later Mesozoic ammonoids. Prolecanitids were a minority among Late Paleozoic ammonoids, which were dominated by the Goniatitida, and showed many features that set them far apart from their contemporaries, including (1) long-term, gradual changes in shell geometry (W-D-S); (2) the most strongly constrained morphospace of any Paleozoic ammonids examined to date; (3) an eight-fold increase in mean suture complexity (three times that of Pennsylvanian goniatitids); (4) high correlations between shell geometry, shell and septal thickness, and suture complexity; (5) short body chambers and, as a consequence, high aperture orientations; (6) indications that cameral liquid may have been used for buoyancy control; and (7) a genus longevity that averaged 14.7 m.y. compared with 5.7 m.y. in Upper Carboniferous goniatitids, and that appears to have been unrelated to suture complexity. Prolecanitids showed a pervasive tendency to increase suture complexity (in the clade as a whole as well as within subclades and in more than 90 percent of ancestor-descendant genera), thus arguing a case for a driven complexity trend. The uniqueness of the prolecanitids calls into question whether they and their Mesozoic descendants, ceratites and ammonites, were strictly analogous to Paleozoic goniatites.
Trilobite alpha diversity and the reorganization of Ordovician benthic marine communities
Authors: Westrop Stephen R. , Adrain Jonathan M.
Published: July 2016

The Ordovician saw the transformation of marine benthic communities from the trilobite-based Cambrian Fauna to the brachiopod-dominated Paleozoic Fauna. An evaluation of the changing importance of trilobites during the Ordovician can be made from accurate assessments of taxonomic richness in various habitats. Here we present a new compilation of trilobite alpha diversity based on field collections and survey of the literature. The data indicate that trilobite species richness within nearshore, shallow subtidal, carbonate buildup and deep subtidal shelf environments was essentially constant between the Late Cambrian and the Late Ordovician. The alpha diversity patterns do not support the notion that trilobites became displaced from inner shelf environments during the Ordovician. Rather, the data are consistent with a decline in relative importance of the group through dilution as newly radiating invertebrate groups entered Ordovician paleocommunities. They also imply that direct interactions between elements of the Cambrian and Paleozoic faunas were not involved in the Ordovician reorganization of paleocommunities. Like many other major faunal transitions during the Phanerozoic, the Ordovician radiations appear to have been essentially non-competitive in nature.
The bio-geometry of mollusc shells
Authors: Rice Sean H.
Published: July 2016

The shells of gastropods and cephalopods grow by production of new material, by the mantle, at the lip of the shell. I derive a model of shell form that allows us to describe the morphology of a shell in terms of independently definable biological parameters. These are (1) the relative rates of shell production at different points around the aperture, (2) the total amount of shell produced per time interval, (3) the growth rate of the aperture, (4) aperture shape, and (5) the orientation of the animal within the shell. Describing shell form in these terms allows us to see what biological changes must occur in development in order to change one shell morphology into another and what constraints are associated with particular morphological transformations. The model shows that it is developmentally easy to derive a slightly coiled limpet shell from that of a high-spired ancestor, but difficult to take the next step to a fully conical limpet. Many, if not most, real gastropod shells are not conical but rather have a convex or concave profile. I show that these forms result from a decoupling of shell production rates from the growth rate of the animal within the shell. The model also shows how truly different forms, such as vermetid snails and heteromorph ammonites, escaped the confines of spiral growth–sometimes by rotating the body within the shell, and sometimes by taking up a growth strategy that does not constrain them to coil. This model is compatible with shell morphometric models that have been widely discussed in the literature but strives toward a different goal: understanding the relationships between the various biological processes involved in shell development.
Brachiopod outline and episodic growth
Authors: Aldridge Anthony E.
Published: July 2016

Accretionary outlines of many brachiopods are closely matched by one or more episodes of logarithmic spiral growth where each episode has a constant growth gradient. An episodic model supports the observations of abrupt change, but not that of gradual change in accretionary growth. A reliable guide to the number of growth episodes is given by the pattern of residuals after fitting a single spiral to an outline. An episodic model exposes subtle variations in growth that are not easily described by visual examination. A three-episode model clarifies a shape difference between two species of the endemic New Zealand genusNeothyris.Direct observation, along with linear measurements and their ratios, was unable to pinpoint that the well-documented dorsoventral compression in one species arises from a growth episode in the ventral valve. Logarithmic spirals about a single coiling axis are not suited for large, disjunct changes in outline for which the moving-frame methods or aperture-deposition models are applicable.
Microfaunal remains from a modern east African raptor roost: patterning and implications for fossil bone scatters
Authors: Stewart Kathlyn M. , Leblanc Leola , Matthiesen Diana P. , West Jolee
Published: July 2016

Fish eagles (genusHaliaeetus) potentially have contributed the bones of their prey to many late Cenozoic concentrations of vertebrate microfossils. To evaluate possible biases in the taxa and skeletal elements preserved in assemblages accumulated by fish eagles, which could affect paleoecological and evolutionary interpretations derived from Cenozoic microfaunal localities, a sample of 1883 bones accumulated by modern African fish eagles (H. vocifer) was collected from a roost near Lake Turkana, Kenya. Characteristics of the bone assemblage include (1) taxonomic composition dominated by fish; (2) diverse but small-sized and ecologically restricted animals including inshore fish, aquatic birds, very small nocturnal mammals (which may have been contributed by other raptors), and small reptiles (possible predators on the roost); (3) poor survivorship for specific categories of skeletal elements; (4) considerable bone breakage for all but the smallest animals; and (5) a distinctive pattern of postcranial fragmentation for bird and mammal elements. The fish eagle element profile has some similarities to those of other diurnal raptors, but its cumulative signature can be distinguished from those of other bone accumulators and includes characteristics that would also be manifest in fossil assemblages. Examination of fossil microfaunas from the Plio-Pleistocene localities of Kanapoi (Kenya), Inolelo (Tanzania), and Olduvai Gorge (Tanzania) shows that the patterns of element preservation for Kanapoi and Inolelo do not match those of the Lake Turkana fish eagle roost. Nonetheless, some aspects of the Olduvai Gorge FLKN assemblage show taxonomic and skeletal similarites. In light of the selective choices of prey by fish eagles, the fauna recovered from Olduvai Gorge FLKN might not accurately reflect faunal diversity or patterns of abundance at this locality during the Pleistocene. Because fish eagles of the genusHaliaeetusare found on three continents, have a fossil record extending to the Miocene, and deposit bones in a habitat conducive to preservation, the taxa preserved at many other late Cenozoic microfaunal sites also might be biased. Therefore, taphonomic profiles of late Cenozoic microfaunal assemblages should be compared against the taphonomic profiles typical of fish eagle roosts before faunal characterizations of sites are applied in analyses of paleoecological evolution.
Shape disassociation and inferred heterochrony in a clade of pachypleurosaurs (Reptilia, Sauropterygia)
Authors: O'Keefe F. Robin , Rieppel Olivier , Sander P. Martin
Published: July 2016

In this paper we analyze the ontogenies of four species of pachypleurosaur (Reptilia: Sauropterygia) occurring in Triassic-age deposits in the Monte San Giorgio region, Switzerland. Preservation of multiple complete specimens representing a growth series from each taxon allows the comparison of ontogenetic trajectories through a space composed of nine variables important in the evolution of the clade. Trajectories are characterized using the multivariate generalization of the allometry equation and then compared through calculations of the angles between allometry vectors. Individual coefficients of vectors are compared after calculation of bootstrapped confidence intervals. Pachypleurosaur ontogeny is found to be allometric and generally conserved, although significant differences between taxa exist. Shape-disassociated allometric changes characterize the transition betweenSerpianosaurusandNeusticosaurus, while allometric changes withinNeusticosaurusare less significant.N. edwardsiiis inferred to have arisen through hypermorphosis. Interpretation of whole-body heterochrony in multivariate analysis is discussed.
A diffusion model of species selection
Authors: Slatkin Montgomery
Published: July 2016

A diffusion model of the distribution of a phenotypic character in a group of species is developed and analyzed. The model incorporates the combined effects of phyletic evolution, speciation and extinction. Directed speciation is modeled by assuming there is some bias to phenotypic changes during speciation. Species selection is modeled by assuming there is some dependence of either speciation or extinction rates on the phenotypic character. Three examples are analyzed to illustrate the use of the model. A model of completely random changes due to both phyletic evolution and speciation shows how between-species differences are established. A model of directed speciation due to multiplicative changes during speciation shows how a simple assumption about the speciation process can produce macroevolutionary trends. A model of species selection due to differences in extinction rates shows how the efficacy of species selection depends on the between-species variance produced both by speciation and by phyletic evolution.
The ecology of MesozoicGryphaea, Exogyra, andIlymatogyra(Bivalvia: Mollusca) in a modern ocean
Authors: LaBarbera Michael
Published: July 2016

Physical models of six species of the Mesozoic bivalve generaGryphaea, Exogyra, andIlymatogyraand hollow hemispheres of comparable size were manufactured, the former from molds of fossil specimens. The survival (maintenance of a position within 1 cm of the sediment-water interface) of populations of these models on 3 sediment types in the lower intertidal of the Gulf of Mexico was monitored over an 18 mo period. Bulk sediment density had no detectable influence on the mean mass density (g cm−3) of the population of models which maintained position at the sediment-water interface. Increased intensity of sediment reworking strongly decreased the probability of survival of the models. Model shells took up orientations consistent with previous laboratory studies and observations of fossils preserved in situ. Some of the models were attacked and broken open by blue crabs and stone crabs, and crab predation was an important source of “mortality” of the models. These results are consistent with the hypothesis that increased sediment reworking and the evolution of durophagous predators in the Cretaceous caused the extinction of exogyrid and gryphaeid bivalves and the near-total elimination of the reclining mode of life in post-Cretaceous times.
Barnacle ecology: is competition important? The forgotten roles of disturbance and predation
Authors: Paine R. T.
Published: July 2016

The view that interspecific competition with balanoid barnacles has caused the evolutionary decline of chthamaloids (Stanley and Newman 1980), is challenged on 3 grounds. First, as a phyletic stock, chthamaloid size, as indicated by the mean adult basal diameter of extant taxa, has been decreasing, probably since the end of the Cretaceous. Small organisms will lose in interspecific competition to larger ones. However small body size reduces the susceptibility to predation and various forms of disturbance, and therefore allows chthamaloids to inhabit intertidal areas denied to balanoids. Second, although many species of Chthamalus occupy a high intertidal “refuge,” there is little evidence that competition is the primary ecological force maintaining them there. Predation is the most significant influence in tropical areas. In many temperate zone communities characterized by intense invertebrate predation or physical disturbance, chthamaloids achieve their maximum density lower in the intertidal than do balanoids or coronuloids. Last, the fossil evidence supporting a decline in chthamaloids is missing. The difficulty of seeking a single mechanism to explain global, multispecific phenomena is discussed.
Crises and extinction in the fossil record—a role for ultraviolet radiation?
Authors: Cockell Charles S.
Published: July 2016

A number of natural events can cause ozone depletion, including asteroid and comet impacts, large-scale volcanism involving the stratospheric injection of chlorine, and close cosmic events such as supernovae. These events have previously been postulated to have been sole or contributory causes of mass extinctions. Following such events, UV-B radiation would have been elevated at the surface of the earth. The possibilities for detecting elevated UV-B as a kill mechanism in the fossil record are discussed. In the case of impact events and large-scale volcanism, the taxa affected by increases in UV-B radiation are likely to be similar to those affected by cooling and by the initial drop in irradiance caused by stratospheric dust injection. Thus UV-B may synergistically exacerbate the effects of these other environmental changes and contribute to stress in the biosphere, although UV-B alone is unlikely to cause a mass extinction. By the same token, however, this similarity in affected taxa is likely to make delineating the involvement of UV-B radiation in the fossil record more difficult. Cosmic events such as supernovae may produce smaller extinction events, but ones that are “cleaner” UV catastrophes without the involvement of other environmental changes.
Duration and habitat of fossil taxa: changes through time in variance and taxonomic selectivity
Authors: Holman Eric W.
Published: July 2016

Variance and taxonomic selectivity were studied as functions of time across the Phanerozoic for duration of genera and families in the fossil record and for habitat of fossil families. The variance of duration increases temporarily before mass extinctions but otherwise decreases across the Phanerozoic, and the variance of habitat increases to an asymptote. For both duration and habitat, the percentage of variance explained by differences among orders and classes shows no temporal trend, whereas the percentage of variance explained by differences among phyla decreases across the Phanerozoic. The latter decrease depends upon the time elapsed since the origination of classes within phyla in the early Paleozoic; a similar decrease appears in differences among classes if the analysis is restricted to orders that originate before the Silurian. The observed patterns can be described by bounded random walks that include some infrequent but large steps.
XXII. Roman Antiquities discovered in Essex. Communicated by Mr. King. In a Letter to the Secretary
Authors: King
Published: July 2016

I take the liberty, through your hands, to lay before the Society, two small fragments of antiquity, which, on account of their singularity, may deserve some little attention, though it is not possible for me at present to give any very full or satisfactory account of them. They were communicated to me by my worthy friend Doctor Griffith; and I shall add what information he was able to obtain with regard to them.
XXIII. Description of the Great Seal of Queen Catherine Parr, the sixth Wife of Henry VIII. from an Impression in the Collection of Gustavus Brander, Esq; F.R. and A.S.S. By Mr. Brooke of the Herald's College, F.S.A.
Authors: Brooke
Published: July 2016

The extreme elegance of the sculpture of the royal seal, the impression of which you favoured me with a sight of, joined to the circumstance of its being as yet unpublished, has induced me to cause a drawing to be made of it, which, with the following description, you may probably think worth communicating to the Society of Antiquaries.
XXVI. Remarks on the Word Romance. By the Rev. Mr. Bowle, F.S.A. In a Letter to the Secretary
Authors: Bowle
Published: July 2016

I Beg leave, through your means, to convey to the Society my sentiments respecting the word Romance; a subject which has already employed the pen of the ingenious Mr. Drake, and others. I hope for this gentleman's particular indulgence, if I differ entirely from him, and join in opinion with Dr. Percy, and the learned Warton, in their sense of the word.
XXXIX. Remarks on an antient Pig of Lead lately discovered in Derbyshire. By Mr. Pegge. In a Letter to Robert Banks Hodgkinson, Esq.
Authors: Pegge
Published: July 2016

Being now returned into the country, I find myself at liberty to take into consideration, and briefly to illustrate, the block, or piece of lead, found in April 1777, on Cromford nethe-Moor, Derbyshire, which may be regarded not only as a curious, but as an important discovery to gentlemen who are either concerned in the mines of our country, or studious of our provincial antiquities.
VIII. A Dissertation on the Gule of August, as mentioned in our Statute Laws. By John Pettingal, D.D.
Authors: Pettingal John
Published: July 2016

It is an observation of Plato in Cratilo, Ος αν τα ονοματα ειδη, εισεται και τα ῶρατματα, “That the knowledge of the etymology “of words, leads to the knowledge of things.” In this view I propose to enquire into the origin of the expression of the Gule of August, which is to be met with in our statutes and elsewhere.
XIII. The Bull-running, at Tutbury, in Staffordshire, considered. By the Reverend Mr. Pegge
Authors: Pegge
Published: July 2016

I know of nothing that affords the inquisitive mind of man so much pleasure, as the developing the original of antient and obscure customs; and if it happens, that former conjectures have miscarried, and men's opinions concerning them have been thereby misled, the satisfaction will then be double, because, at the same time that you establish a truth, you are routing and convicting an error.
XVI. Observations on Dr. Percy's account of Minstrels among the Saxons. By Mr. Pegge
Authors: Pegge
Published: July 2016

Dr. Percy, in that part of the Essay on the Ancient English Minstrels, prefixed to his Reliques of Ancient English Poetry, which concerns the state and condition of these people in the Saxon times, previous to the Norman conquest, has given us, in my opinion, a false, or at best, an ill-grounded idea of their rank and condition within that period. This imaginary notion, for such I take it to be, I propose to discuss in the shortest manner I can.
XX. Observations on an Inscription in the Church of Sunning-Hill, Berks. By Dr. Milles, Dean of Exeter, and President of the Society
Authors: Milles
Published: July 2016

The parish church of Sunning-Hill in Berkshire, is a specimen, both in its form and size, of the earlier parochial churches which were built in this kingdom, consisting only of a nave, and a small chancel, divided by a square belfry tower.
XXVII. Extract of two Letters from Dr. John Burton, of York, to Dr. Ducarel, concerning Roman Antiquities discovered in Yorkshire, 1770
Authors: Burton John
Published: July 2016

Since the consular coin of Marius was found, there have been other Roman coins dug up near the same place. Lately also several urns and Roman coins, about three miles east by north of Horden. Also in digging lately about a mile south of York for gravel, many pieces of urns were found, some of a beautiful red clay; some were impressed with letters. Mr. Smith, of New Buildings, near Thirsk, is very assiduous in searching after Roman antiquities, and takes great pleasure in collecting them. Last summer, in digging for gravel near Huddersfield, in the West Riding, several urns were found with coins in them.
XXXII. Observations on a Greek Inscription brought from Athens. By Daniel Wray, Esquire
Authors: Wray Daniel
Published: July 2016

I Take the liberty to communicate to the Society an ancient inscription, which I met with some months ago in the possession of Mr. Jones, of Finchley, a worthy old gentleman, who is retired from business to a pleasant spot in that village.
XXXVI. A succinct and authentic Narrative of the Battle of Chesterfield, A. D. 1266, in the Reign of King Henry III. By Mr. Pegge
Authors: Pegge
Published: July 2016

Baldwin Wake the fourth, whose name is otherwise written: Le Wac, was the possessor of the great manor of Chesterfield, in the 50th year of King Henry III, or A. D. 1266, when the battle, hereafter to be related, happened. This family had a large estate in the counties of Lincoln, Leicester, Northampton, Nottingham, and Hertford; and their chief residence was at Brun, or Burne, in Lincolnshire, and Lidell, in Cumberland. As to Chesterfield, which accrued to them by the marriage of Baldwin the third, grandfather of Baldwin above-mentioned, with Isabella, daughter of William Briwer, the description of it runs thus; “manerium de Chestre-“feld, cum redditibus et servitiis duorum tenementorum suo-“rum deNewbold, Barley (now Barlow), Whittington Magna, “Topton (now Tapton), Boythorp, et Ecchington, et totum wa- “pentachum prædictum;” meaning the wapentake or hundred of Scarsdale.
XI. The Question considered, whether England formerly produced any Wine from Grapes. By the Reverend Mr. Pegge
Authors: Pegge
Published: July 2016

It has been a prevailing notion, that England formerly produced some wine; and something in support of that opinion was offered to the Society in 1763, on the introduction, progress, state, and condition, of the vine in England, and the memoir was so well received as to merit a place in the Archaeologia. A gentleman of great knowledge, however, a considerable Antiquary, and a worthy member of the Society, has since been pleased to combat this notion, and to assign certain reasons for his dissent, in that noble and very elaborate work Observations on the more ancient Statutes, &c. p. 207, & seq. Whence it should seem a duty incumbent upon me, either to give up the point in question, or to invalidate his arguments; and the latter, under the Society's favour, I propose here to attempt, with all proper deference and regard to the superior abilities of the Honourable and very learned Mr. Barrington.
XVII. Observations on some Roman Altars, found in August 1771, near Graham's Dyke. By Mr. Gough
Authors: Gough
Published: July 2016

The workmen employed to cut the new canal of communication between the Forth and Clyde, digging in August 1771, near one of the most considerable stations on Graham's Dyke, at Auchindavie, had the good fortune to light on four altars of different sizes, with inscriptions on one side of each, very legible. They had been thrown into a pit with the iron heads of two large sledge hammers, and the shoulders of a bust of the same materials with the altars, viz. of the grit stone of the county. Whether these hammers had belonged to the proprietor of the altars, or were used to demolish the temple, is uncertain. But as they were all buried together in the same pit and at the same time, they had probably served some purposes about the temple or fort, perhaps for knocking down victims.
XXVIII. Account of opening one of the largest Barrows on Sandford Moor, Westmoreland, in a Letter from Mr. William Preston, dated Warcop Hall, Sept. 5, 1766, to Bishop Lyttelton
Authors: Preston William
Published: July 2016

The labourers began by driving a level, and for some time found nothing worth notice. At length one of them, digging on the top of the barrow downwards, turned up, within half a yard from the surface, a piece of an urn, and soon after came to what he thought an urn, fixed, in a large pot or vessel, and containing a small quantity of white ashes.
XXXI. On the Expiration of the Cornish Language. In a Letter from the Hon. Daines Barrington, Vice Pres. S.A. to John Lloyd, Esquire, F.S.A.
Authors: Barrington Daines
Published: July 2016

The precise time when any ancient language ceases to be spoken by the inhabitants of a country seems to be interesting not only to the philologist, but to the antiquary; I shall therefore desire you would lay before the Society the following particulars with regard to what I conceive to be the last spark of the Cornish tongue.
XLII. Observations on Two Jewels in the Possession of Sir Charles Mordaunt, Bart. By the Rev. Mr. Pegge
Authors: Pegge
Published: July 2016

These two pieces were dug out of a bank near Lord Willoughby de Broke's seat at Compton-Mordock, alias Compton-Vernai, in the county of Warwick, A. D. 1774. Three sculls were found with them lying in a row. The pieces had been suspended on the necks of two of the parties there interred, as being their most valuable trinkets; and are now the property of Sir Charles Mordaunt, a respectable member of this Society, on whose estate they were found.
XLIII. An Account of the Body of King Edward the First, as it appeared on opening his Tomb in the Year 1774. By Sir Joseph Ayloffe, Bart. V.P.S.A. and F.R.S.
Authors: Ayloffe Joseph
Published: July 2016

The royal warrants repeatedly issued by King Edward the Third, and his two immediate successors, directed to the treasurer and chamberlains of their exchequer, De cera renovanda circa corpus regis Edwardi primi; and the total silence of all our historians, and public records, as to a similar attention having been paid to the corpse of any other of our deceased momarchs; are circumstances, that not only indicate the high veneration in which King Edward the First was held during a long series of years after his decease; but when considered, together with the strong injunctions under which, it is said, that king in his last moments laid his son, to send his heart to the Holy Land, attended by 140 knights, and to carry his remains along with the army until Scotland was reduced to obedience, gave rise to an opinion, that upon his decease a more than ordinary care was taken to preserve his body from putrefaction; and that, in subsequent times, the utmost endeavours were used for preventing its decay.
I. Observations on the Julia Strata, and on the Roman Stations, Forts, and Camps, in the Counties of Monmouth, Brecknock, Caermarthen, and Glamorgan. By the Rev. William Harris, Prebendary of Landaff, and Curate of Caireu
Authors: Harris William
Published: July 2016

It is probable that Julius Frontinus, Prefect of the Legion 2da Augusta under Vespasian, who was detached to reduce the Silures, and from whom Julia Strata is said to have been denominated, passed the Severn three little miles below Oldbury, at Awst passage, perhaps termed from that legion, Trajectus, Augustæ; as the Monk of Ravenna stiles Caerleon Isca Augusta, and the Britons at this day call the month of August Mîs Awst.