Women are underrepresented in paleontology. Despite more women students, representation at senior levels remains low. To advance professionally, scientists must disseminate their research through peer-reviewed publications. We examine gendered authorship patterns in Paleobiology to ask whether the publishing infrastructure supports the Paleontological Society's gender-equity goals. We reviewed all papers published in Paleobiology from its inception in 1975 through 2021. For each paper, we recorded each author, the author's position in the author list, and the total number of authors on each paper. We coded gender based on a combination of personal communication and pronouns used in publicly available information. We compared author demographics with anonymized membership data from the Paleontological Society. Over the journal's run, the number of authors per paper increased due to cultural shifts toward collaborative work and acknowledging student contributions with coauthorship. These trends contribute to proportionally more women authors, beginning in the early 2000s. Despite these increases, women remain chronically underrepresented. In 2018, 2019, and 2021, the proportion of women authors in Paleobiology paralleled membership in the Paleontological Society. However, in 2020, Paleobiology published fewer women authors than expected based on society membership. This echoes declines in women's scholarly productivity in the first year of the COVID-19 pandemic observed across many disciplines. We offer four recommendations: (1) practice double-anonymous peer review; (2) recruit editors from diverse backgrounds who invite reviewers with diverse backgrounds; (3) democratize manuscript review by selecting reviewers from a disaggregated reviewer database; and (4) gather and analyze demographic data for both submissions and publications.

Angiosperms first appeared in the fossil record as pollen during the Valanginian-Hauterivian; they spread out of the tropics in the Aptian and Albian, and radiated in the Late Cretaceous. Despite these general patterns, details of the taxonomic, geographic, and ecological evolution of Cretaceous angiosperms are relatively poorly known because only a handful of Early and mid-Cretaceous macrofloras have been reported. This is the first detailed report of a fossil leaf flora from the Cedar Mountain Formation from the mid-Cretaceous of the Western Interior. We describe a flora that is overwhelmingly dominated by angiosperms (152 of 153 identified specimens are angiosperms) from the Albian-Cenomanian transition that is preserved in a clay- and carbonate-rich, lacustrine mudstone from the uppermost Cedar Mountain Formation of Emery County, Utah. We recognize 18 leaf morphotypes, all of which are dicotyledonous angiosperms. The majority of the Cedar Mountain morphotypes have taxonomic affinities with forms of similar age described from the Atlantic and Gulf coastal plains and other localities from the Western Interior. From this, we infer that a relatively diverse angiosperm flora grew along the margins of a small pond on the coastal plain. Palynological preparations of the fossil matrix were barren; however, previous studies of other facies within the formation showed that both conifers and ferns were important components of the regional vegetation during Cedar Mountain time. The effective absence of conifers and ferns in this macroflora and low leaf mass per area values among the angiosperms measured suggests that even at the Early-Late Cretaceous transition, angiosperms had come to dominate some sites, particularly those that were disturbed or seasonally ephemeral, where fast-growth or seasonal deciduousness would have been favored.

The Soap Wash flora contains 152 angiosperm leaf fossils from the Albian-Cenomanian boundary of central Utah. The flora exhibits many well-preserved examples of insect folivory for which the extent and type of damage on each leaf was recorded. Fewer than half of the specimens in the collection exhibit insect damage and most of the leaf damage affects less than five percent of the leaf area. Damage was distributed unevenly across the 18 leaf morphotypes described in the flora. Nineteen damage types were recognized. Most of the damage was of a generalized type, dominated by indiscriminate removal of leaf tissues (whole leaf feeding). We observed no correlation between leaf mass per area (MA) and the degree of damage by herbivores, which contrasts with Cenozoic and modern patterns. The low rate, modest area, and low diversity of damage type is similar to patterns reported through the Late Cretaceous and is consistent with a plateau in insect folivore diversity that persisted through the end of the Mesozoic. The preponderance of generalized damage types dominated by whole leaf feeding may reflect (1) the early stage in angiosperm radiation represented by this flora, and (2) the associated lag in folivore diversification and specialization.

Aim Early in their evolution, angiosperms evolved a diversity of leaf form far greater than that of any other group of land plants. Some of this diversity evolved in response to varying climate. Our aim is to test the global relationship between leaf form in woody dicot angiosperms and the climate in which they live.Location We have compiled a data set describing leaf form(using 31 standardized categorical characters) from 378 natural or naturalized vegetation sites from around the world. Our data include sites from all continents except Antarctica and encompass biomes from tropical to taiga, over a range of elevations from 0.5 m to over 3000 m.Methods We chose the Climate Leaf Analysis Multivariate Program sampling, scoring and analytical protocols to test the relationships between climate and leaf form, which is based on canonical correspondence analysis. Cluster analysis evaluates the role of historical factors in shaping the patterns, and pairwise Pearson correlations examine the relationships among leaf characters.Results Woody dicot leaf characters form a physiognomic spectrum that reflects local climate conditions. On a global scale, correlations between leaf form and climate are consistent, irrespective of climate regime, vegetation type or biogeographic history. Relationships with temperature variables are maintained even when leaf margin characters, regarded as being particularly well correlated with mean annual temperature, are removed.Main conclusions In natural woody dicot vegetation an integrated spectrum of leaf form has developed across multiple leaf character states and species. This spectrum appears more strongly influenced by prevailing climate than biogeographic history. The covariation of leaf traits across species suggests strong integration of leaf form. New methods of exploring structure in multidimensional physiognomic space enable better application of leaf form to palaeoclimate reconstruction.

The Soap Wash flora from the Cedar Mountain Formation of Emery County, Utah (Albian-Cenomanian bbuildary) consists almost entirely of angiosperms and is positioned Stratigraphically near the first appearance of flowering plants in this region. We applied both univariate (leaf margin analysis LMA, and leaf area analysis-LAA) and multivariate (Climate Leaf Analysis Multivariate Program CLAMP) methods to the 17 morphotypes recognized in the flora to reconstruct palaeoclimate. LMA produced a mean annual temperature (MAT) estimate ranging from 19 degrees C to 26 degrees C. CLAMP yielded 16 degrees C-18 degrees produced a mean annual precipitation (MAP) of 81 cm, while CLAMP generated a mean growing season precipitation of 134-187 cm, within the range of standard error for the LAA estimation. CLAMP also estimated a nine to ten month growing season with some temperature seasonality and substantial seasonality in precipitation. This reconstruction is broadly consistent with sedimentological data that suggested a semiarid to monsoonal precipitation regime for the region and with climate models that predict warm summers and strong winter seasonality in precipitation. Leaf physiognomic parameters of the Soap Wash flora fall within the range of variation circumscribed by the calibration sets of all three methods, so the differences in reconstructed MAT values cannot be explained exclusively by this kind of systematic error. We propose two alternative hypotheses: First, modern leaf form-climate relationships may not yet have evolved. This seems unlikely because CLAMP has been successfully applied to older material elsewhere. Second, the Soap Wash flora may be out of equilibrium with its prevailing climate due to contemporaneous rapid climate flux. If correct, this pattern may suggest a link between mid-Cretaceous environmental perturbations and the rapid diversification and geographic spread of flowering plants. (C) 2014 Elsevier Ltd. All rights reserved.

Paleogeographic reconstructions hypothesize that during the Cretaceous, South America was split into northern and southern portions by an epeiric seaway. Although the location, extent, and duration of this ancient seaway is debated, some propose that the resulting separation produced a northern South American biota that more closely resembled other equatorial biotas, distinct from a southern South American biota that more closely resembled other austral biotas. Palynological data from nine South American countries, five equatorial representatives (including the southeastern U.S. and northwestern Africa), and three austral representatives (Antarctica, Australia, and New Zealand) were assembled into a database that includes more than 450 genera from more than 150 localities spanning the Late Cretaceous and Paleocene epochs. Principal components and cluster analyses of the palynological data separate northern South America from southern South America during the Maastrichtian and Paleocene. During these epochs, northern South America clusters with the equatorial representatives; whereas southern South America clusters with austral representatives. These results suggest that biogeographic barriers, such as epeiric seaways, may have played a significant role in the evolution of distinct terrestrial biotas in South America during the Late Cretaceous and Paleocene. KEY WORDS. South America. Cretaceous. Paleocene. Biogeography. Palynology. Epeiric seaway.

The Hell Creek Formation in eastern Montana has yielded well-preserved leaf megafossil localities that provide insight into the vegetation and climate of the latest Cretaceous. Among the most basal, the PDM locality (UCMP [University of California Museum of Paleontology] PB99057 = MOR [Museum of the Rockies] HC-278) occurs in channel sandstones ~10 m above the underlying Fox Hills Formation. The locality represents a fluvial/estuarine environment. Leaf megafossil impressions were preserved on clay drapes within the channel. Angiosperms dominated the flora (13 of 17 morphotypes). Dryophyllum subfalcatum and “Vitis” stantoni, two common morphospecies in the Hell Creek Formation,...

Questions of biotic and environmental change during deposition of the Upper Maastrichtian Hell Creek Formation require a robust and replicable system for intra-formational correlation of fossil localities. In this paper, we present a carbon isotope chemostratigraphic curve based on terrestrial organic carbon. Data were taken from a complete measured section spanning the full 93 m of the Hell Creek Formation at our study site. Sedimentary beds were described at the centimeter scale, and samples for carbon isotope analysis were taken at ~10 cm intervals. Each sedimentary bed was analyzed in thin section, and grain-size data were assembled based on petrographic...

The percentage of woody dicots with entire-margined leaves in a flora is known to be positively correlated with mean annual temperature (Leaf Margin Analysis — LMA) but this relationship is not globally uniform. In particular the floras of Australia and New Zealand have been regarded as displaying a different physiognomic relationship to climate than floras seen in the Northern Hemisphere. This difference is more marked in New Zealand where the LMA relationship appears entirely absent. Here we amass data for both Northern and Southern hemispheres using standard protocols and show that regional variations in the leaf margin–mean annual temperature relationship are real but become less significant when other characters are included. Even New Zealand falls into line and most of the mean annual temperature signal in New Zealand floras is encoded in non-margin features. We introduce a new CLAMP (Climate Leaf Analysis Multivariate Program) calibration dataset for the Southern Hemisphere, comprising leaf physiognomic data from Argentina, Bolivia, South Africa, Australia, New Zealand and other Pacific Islands that offers comparable precision for climate prediction to similar datasets derived from the Northern Hemisphere.

Many workers consider the Cretaceous-Paleogene extinction the archetypal catastrophic pulse event caused solely by the Chicxulub bolide impact. However, based on a global scale analysis of marine animals, the Cretaceous-Paleogene boundary is a candidate for an extinction enhanced by the coincidence of press and pulse disturbances. We make a preliminary test of key predictions of the press-pulse hypothesis using palynological data. We document a local palynological extinction of 21% at the Cretaceous-Paleogene boundary, which is consistent with extinction rates of 15% to 30% at other localities in the Hell Creek type area and throughout North America. We also fi nd a decline in the number of dicot angiosperm pollen taxa between !3.5 m and !2.5 m below the boundary. We document a low-palynospecies-richness interval between !1.4 m and !1.0 m that includes extirpation, but not extinction, of some palynospecies. These changes in species richness are not correlated with changes in depositional style or pollen preservation, indicating that they may represent a biological rather than entirely taphonomic signal. Review and reanalysis of previously published data from other localities in the western interior of North America suggest similar declines in species richness within approximately the same stratigraphic interval. However, many of the species absent during the low-species-richness interval reappeared before the Cretaceous-Paleogene boundary, suggesting changes in community structure and composition before the terminal Cretaceous event—a key prediction of the press-pulse hypothesis—rather than gradual extinction in the latest Cretaceous.

Single-cause mass extinction scenarios require extreme conditions to generate sufficiently strong kill mechanisms. Such dire effects are commonly at odds with the taxonomic selectivity that characterizes most extinction events. In response, some researchers have proposed that the interaction of a variety of factors typify episodes of elevated extinction. Previous work (Arens & West 2008 Paleobiology 34:456-471) has shown that a combination of press and pulse disturbances increases the probability of elevated extinction. The press/pulse contrast is borrowed from community ecology, where researchers have long recognized that the ecological response to long-term stress differs from that of an instantaneous catastrophe. Scaled to the macroevolutionary level, press disturbances alter community composition by placing multigenerational stress on populations. Press disturbances do not necessarily cause mortality, but reduce population size by a variety of mechanisms such as curtailed reproduction. Pulse disturbances are sudden catastrophic events that cause extensive mortality. Either press or pulse disturbances of sufficient magnitude can cause extinction, however elevated extinction occurs more commonly during the coincidence of lower-magnitude press and pulse events.

![Figure][1] Deccan plateau basalts. Lava from Deccan volcanism formed distinct layering. CREDIT: GSFC/NASA In the Review “The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene boundary” (P. Schulte et al. , 5 March, p. [1214][2]), the terminal Cretaceous

Write an abstract, similar to one you might submit to a scientific conference, describing your analysis. Your abstract may not exceed 200 words, and should include the following elements: • Title (maximum 70 characters including spaces) that tells the main idea of the research. • Background information that explains the context of the research and poses the research question. 3 Check out the abstract volume from a recent meeting of the Geological Society of America for examples of how scientific abstracts in geology are composed. Paleoecology Exercise 7 • Method that gives the main idea of the procedure you followed. • Results. Was your result statistically significant? • Interpretation of the results and the primary conclusion of the analysis. Questions for Further Thought 1. What sources of error can you find in this method? Consider its basic idea (e.g., the theoretically predicted consequence of competition), the design of the analysis (e.g., the resources considered and how resource use is reconstructed from fossils), and execution of the method (e.g., what you actually did). Note: Nan Crystal Arens originated the idea for this exercise and has kindly allowed me to develop it. References Hermoyian, C.S., L.R. Leighton, and P. Kaplan. 2002. Testing the role of competition in fossil communities using limiting similarity. Geology 30:15-18. Hutchinson, G.E. 1959. Homage to Santa Rosalita. American Naturalist 93:145-159. MacArthur, R.H. 1972. Geographical Ecology. Princeton University Press, Princeton, NJ, 269 p.

In order to test the assertion that the carbon-isotopic composition of the ancient atmosphere (delta(CO2)-C-13) can be reconstructed from the carbon-isotopic composition of fossil terrestrial plant tissues across a variety of environments, the delta C-13 value of land-plant tissues isolated from modern fluvial sediments was compared to that of today's atmosphere. Plant stem and leaf fragments were isolated from organic carbon-rich sediments of the Black River in Jamaica, which drains a basin containing only C3 ecosystems. Sediment was sampled at 12 sites along a dissolved salt-content gradient, from the coastal plain to near its mouth, which allowed evaluation of the effect of salt influence on the organic carbon-isotope signature. Many properties of the sediment varied systematically with salt content (e.g., mass-percent carbonate, abundance of palynomorphs, delta C-13 and delta O-18 values of carbonate), confirming a significant and increasing marine influence closer to the mouth of the river. The delta C-13 value of total organic carbon systematically decreased by similar to 2 parts per thousand with increased NaCl concentration, indicating the presence of a mixing line between marine and terrestrial organic inputs. In contrast, for leaf and stem isolates, there was no significant dependence of delta C-13 value on NaCl concentration, suggesting that the isotopic signature of the integrated terrestrial contribution is independent of the salt content of the depositional environment. The mean values of all isolates retrieved from the sediments predicted a delta(CO2)-C-13 value of -9.7 (+/-1.0) for leaf material and -8.2 (+/-1.7) for stems. Both of these values are within similar to 1 parts per thousand of recent regional-scale measurements of atmospheric delta(CO2)-C-13 value.

Previous discussions of mass extinction mechanisms generally focused on circumstances unique to each event. However, some have proposed that extensive volcanism combined with bolide impact may offer a general mechanism of mass extinction. To test this hypothesis we compared generic extinction percentages for 73 stages or substages of the Mesozoic and Cenozoic. We found that the highest frequency of intervals with elevated extinction occurred when continental flood basalt volcanism and bolide impact co-occurred. In contrast, neither volcanism nor impact alone yielded statistically elevated extinction frequencies. Although the magnitude of extinction was uncorrelated with the size of the associated flood basalt or impact structure, crater diameter did correlate with extinction percentage when volcanism and impact coincided. Despite this result, case-by-case analysis showed that the volcanism-impact hypothesis alone cannot explain all intervals of elevated extinction. Continental flood volcanism and impact share important ecological features with other proposed extinction mechanisms. Impacts, like marine anoxic incursions, are pulse disturbances that are sudden and catastrophic, and cause extensive mortality. Volcanism, like climate and sea level change, is a press disturbance that alters community composition by placing multi-generational stress on ecosystems. We propose that the coincidence of press and pulse events, not merely volcanism and impact, is required to produce the greatest episodes of dying in Phanerozoic history.

Reconstruction of the carbon isotope composition of atmospheric CO 2 is critical to the understanding of long‐term global carbon cycling. We have suggested that the δ 13 C value of land plant carbon ( δ 13 C p ) preserved in the geologic record should reflect the δ 13 CO 2 at the time during which the plants grew ( δ 13 C a ), based on a meta‐analysis of modern plant data. Here we present the results of laboratory experiments designed to quantify the relationship between plant tissue δ 13 C and δ 13 CO 2 values under varying environmental conditions, including differential p CO 2 ranging from 1 to 3 times today's levels. As predicted, plants grown under elevated p CO 2 showed increased average biomass compared to controls grown at the same temperature. Across a very large range in δ 13 C a (≈24‰) and p CO 2 (≈740 ppmv) we observed a consistent correlation between δ 13 C a and δ 13 C p ( p < 0.001). We show an average isotopic depletion of −25.4‰ for aboveground tissue and −23.2‰ for belowground tissue of Raphanus sativus L. relative to the composition of the atmosphere under which it formed. For aboveground and belowground tissue, grown at both ∼23°C and ∼29°C, correlation was strong and significant ( r 2 ≥ 0.98 and p < 0.001); variation in p CO 2 level had little or no effect on this relationship. These results validate our initial conclusion that in the absence of environmental stress, plant δ 13 C primarily reflects atmospheric δ 13 CO 2 linearly across p CO 2 levels; the demonstrated excellent correlation in δ 13 C a and δ 13 C p suggests a high level of predictive power across varying environmental conditions.