Adaptive Radiations in the Context of Macroevolutionary Theory: A Paleontological Perspective

This is the author's accepted manuscript, the published version can be found here http://dx.doi.org/10.1007/s11692-012-9165-8.Adaptive radiations are often invoked anytime clades show significant bursts of diversification, but it is important to not simply assume that any radiating clade constitutes an adaptive radiation. In addition, several highly relevant macroevolutionary concepts including the Turnover Pulse Hypothesis, the Effect Hypothesis, exaptation, and species selection, have not been considered in the adaptive radiations literature. Here, these concepts are integrated into the theory of evolutionary radiations in general, and adaptive radiations in particular, and different types of evolutionary radiations are identified, including geographic radiations. Special emphasis is placed on considering the role that abiotic as opposed to biotic factors may play in motivating diversification during evolutionary radiations. Further, recent paleontological data suggesting that rather than organismal adaptation it may be principally abiotic factors, such as climate change and a taxon’s presence in a geographically complex region, that cause clades to diversify will be described. The fossil record, the source of the initial hallmark examples of adaptive radiation, now appears to show little concrete support for this phenomenon

Systematic revision of the Olenelloidea (Trilobita, Cambrian)

Phylogenetic analyses for all the available species comprising eight clades of trilobites within the monophyletic superfamily Olenelloidea (Trilobita, Cambrian) are presented….https://elischolar.library.yale.edu/peabody_museum_natural_history_bulletin/1044/thumbnail.jp

Revised Biostratigraphy, Systematics, and Paleobiogeography of the Trilobites from the Middle Cambrian Nelson Limestone, Antarctica

23 p., 19 fig., 2 tableshttp://paleo.ku.edu/contributions.htm

The Geography of Evolution and the Evolution of Geography

This is the publisher's version, also available electronically from http://link.springer.com/article/10.1007%2Fs12052-012-0414-1.Insights into the geography of life have played a fundamental role in motivating major developments in evolutionary biology. The focus here is on outlining some of these major developments, specifically in the context of paleontology, by emphasizing the significance of geographic isolation and allopatric speciation, punctuated equilibria, and the Turnover Pulse Hypothesis to evolutionary theory. One of the major debates in evolution concerns the relative contributions of abiotic and biotic factors to macroevolution, and each one of these developments increasingly suggested that it was climatic and geologic factors, rather than competition, that played the primary role in motivating macroevolution. New technical developments, including in the area of Geographic Information Systems, allow continued detailed testing of the relative roles that biotic as opposed to abiotic factors play in causing evolution, and some of the work in this area will also be described

Biogeography and the Cambrian radiation of arachnomorph arthropods

Biogeographic patterns in primarily Cambrian arachnomorph taxa are investigated using a recently constructed phylogenetic hypothesis in order to explore the biogeographic context of the Cambrian radiation. A modified version of Brooks Parsimony Analysis is employed to elucidate patterns of vicariance and geodispersal in taxa from six regions (Laurentia, Baltica, Siberia, Australia, Africa and China). Well resolved vicariance and geodispersal trees are very similar and reconstruct Laurentia and China as sister areas. This close area relationship between Laurentia and China provides extensive evidence for congruent vicariance and range expansion in Cambrian arachnomorphs, while data from trilobites do not show this pattern. Our results imply that cyclic events (such as sea-level change), in conjunction with dispersal ability, may have been more important than tectonic events in generating the biogeographic patterns we observed in Cambrian arachnomorphs. Further, the greater degree of dispersal in various non-trilobite arachnomorph lineages relative to trilobites is correlated with greater extinction resistance across the early-Middle Cambrian boundary

Sharks That Pass In The Night: Using GIS to Investigate Competition in the Cretaceous Western Interior Seaway

This is the author's accepted manuscript, also available at http://dx.doi.org/10.1098/rspb.2010.1617One way the effects of both ecology and environment on species can be observed in the fossil record is as changes in geographical distribution and range size. The prevalence of competitive interactions and species replacements in the fossil record has long been investigated and many evolutionary perspectives, including those of Darwin, have emphasized the importance of competitive interactions that ultimately lead one species to replace another. However, evidence for such phenomena in the fossil record is not always manifest. Here we use new quantitative analytical techniques based on Geographical Information Systems and PaleoGIS tectonic reconstructions to consider this issue in greater detail. The abundant, well-preserved fossil marine vertebrates of the Late Cretaceous Western Interior Seaway of North America provide the component data for this study. Statistical analysis of distributional and range size changes in taxa confirms earlier ideas that the relative frequency of competitive replacement in the fossil record is limited to non-existent. It appears that typically, environmental gradients played the primary role in determining species distributions, with competitive interactions playing a more minor role

Middle Devonian proetid fauna

176 p. : ill. ; 26 cm.Includes bibliographical references (p. 167-176)."This study considers the biogeographic origins, evolutionary affinities, and patterns of diversification and extinction in a portion of the Lower and Middle Devonian proetid trilobite fauna of eastern North America. Four generic clades comprising about 45 species are known from the strata of the upper Emsian (Sawkillian) Bois Blanc Limestone and Schoharie Grit, the Eifelian (Southwoodian) Onondaga Limestone, and the Givetian (Cazenovian, Tioughniogan, Taghanic) Hamilton Group. These taxa have traditionally been assigned to the subfamilies Proetinae Salter, 1864, and/or Dechenellinae Pribyl, 1946. These are Crassiproetus Stumm, 1953a, Basidechenella Richter, 1912, Dechenella Kayser, 1880, and Monodechenella Stumm, 1953a, which were originally considered to be closely related. A higher-level phylogenetic analysis of the Proetinae is conducted to see if these taxa were indeed closely related and thus represent a single endemic radiation of species in eastern North America or rather a series of independent lineages in that region. In the course of discerning characters that defined the Proetinae, it was discovered that Monodechenella lacks several of the characters that define the Proetinae, and the members of this genus therefore must be excluded from this subfamily. They instead appear to belong to a larger group informally referred to as the 'Thebanaspis clade,' which appears to be closely related to the Proetinae. A phylogenetic analysis is performed on proetine ingroup taxa using 21 taxa and 53 characters, and several of the major generic clades in the Proetinae are considered. The phylogenetic analysis of the Proetinae is used to ascertain the ancestral biogeographic states for the three genera in the Proetinae that form an important component of the Lower and Middle Devonian trilobite fauna of eastern North America. This information is used to determine if these taxa are ancestrally present in eastern North America or rather represent a series of invasions from other biogeographic regions. Other taxa occurring in eastern North America at this time appear to represent elements that invaded from Armorica. This invasion of taxa has been related to the collision between plates that produced the Acadian Orogeny during the Middle Devonian. Patterns in these proetid taxa are compared with those known for other groups to ascertain what control the Acadian Orogeny as a biogeographic event may have had on the appearance of these taxa in eastern North America. Phylogenetic analysis is then performed on all available species in each of these generic clades that occur in eastern North America. Species that belong to these clades but which hail from other biogeographic regions are also considered. These phylogenies were used to assess macroevolutionary patterns such as diversification and extinction within each of these clades in eastern North America. In addition to being an important paleogeographic event, the Acadian Orogeny also caused major paleoenvironmental changes. The impact of these changes on the proetid fauna of eastern North America is assessed. It appears that a phenomenon analogous to Vrba's (1985, 1992) Turnover Pulse Hypothesis may have mediated elevated speciation rates in the proetid taxa over the period considered. However, eventually the profound changes in environment appear to have led to the extinction of much of the proetid trilobite fauna of eastern North America. Information on patterns of occurrence in different geographic regions is combined with information from the phylogenetic analyses of the individual generic clades to consider large-scale biogeographic patterns in the late Lower and Middle Devonian. A method for considering biogeographic patterns using cladistic information is developed. This method is based on Brooks Parsimony Analysis, but it allows multiple events of range expansion and subsequent vicariant splitting to occur within each generic clade. This biogeographic method was used to evaluate the relationships between the Arctic, Armorican, and eastern North American paleobiogeographic regions. The relationships between the different major sedimentary basins in eastern North America, the Appalachian, Illinois, and Michigan basins, are also considered. Finally, the origin of major evolutionary faunas in the fossil record is discussed. Included is a brief discussion of a depauperate proetid fauna of the Emsian and Eifelian whose members do not belong to the four generic clades considered in detail. In this work four new genera are recognized: Plesiowensus, Arcticormistonia, Aayemenaytcheia, and Milesdavis. In addition, 12 new species are described: Arcticormistonia edgecombei, Crassiproetus halliturgidus, C. neoturgidus, C. stummi, C. schohariensis, Basidechenella cartwrightae, B. timwhitei, Dechenella perscheii, D. carvalhoae, Pedinodechenella modelli, Milesdavis eldredgei, and Monodechenella legrandsmithi. Diagnoses and discussions for all of the taxa considered are presented"--P. 4