Selectivity in the evolution of Palaeozoic arthropod groups, with focus on mass extinctions and radiations: a phylogenetic approach

Mass extinctions are known to be extraordinary events during which the normal rules of natural selection do not apply. Evidence points to the operation of a different selective regime, one where clade-level properties are selected upon; however, it is still unclear whether survivorship rules apply across different extinction events, the consequences of differential responses in diversity and disparity during extinction events, and the factors governing subsequent recoveries. This dissertation explores these issues by studying three clades of arthropods that experience multiple extinction events, allowing for the effect of different mass extinctions on the same group to be compared utilizing phylogenetic methodology. Three phylogenies where generated, one each for Stylonurina, Eurypterina, and Aulacopleuroidea. Variations in diversity, disparity, and volatility, are compared across these clades for two extinction events: the end-Ordovician (443 Ma) and the late Devonian (385- 359 Ma). Consistent differences in how morphospace occupation changes across the end- Ordovician and late Devonian mass extinction events reveal that the underlying driving factors of individual extinction events can result in very different selective pressures, suggesting that it may not be possible to identify general survivorship rules for all mass extinctions. Ecology is revealed to be a major factor behind the responses of individual species to the late Devonian biodiversity crisis. The somewhat contradictory selective signal exhibited by the studied clades reveals how different aspects of ecology can influence diversity, disparity and volatility in different ways, each influencing aspects of clade survival and recovery in different ways. The results also demonstrate the bearing of the evolutionary history of a clade on such studies. Contingency is an important factor in determining the response of clades to mass extinctions, and only through having a firm understanding of the history of a group can such factors be appropriately accounted for

Babes in the wood – a unique window into sea scorpion ontogeny

A grant from the One-University Open Access Fund at the University of Kansas was used to defray the author’s publication fees in this Open Access journal. The Open Access Fund, administered by librarians from the KU, KU Law, and KUMC libraries, is made possible by contributions from the offices of KU Provost, KU Vice Chancellor for Research & Graduate Studies, and KUMC Vice Chancellor for Research. For more information about the Open Access Fund, please see http://library.kumc.edu/authors-fund.xml.BACKGROUND: Few studies on eurypterids have taken into account morphological changes that occur throughout postembryonic development. Here two species of eurypterid are described from the Pragian Beartooth Butte Formation of Cottonwood Canyon in Wyoming and included in a phylogenetic analysis. Both species comprise individuals from a number of instars, and this allows for changes that occur throughout their ontogeny to be documented, and how ontogenetically variable characters can influence phylogenetic analysis to be tested. RESULTS: The two species of eurypterid are described as Jaekelopterus howelli (Kjellesvig-Waering and Størmer, 1952) and Strobilopterus proteus sp. nov. Phylogenetic analysis places them within the Pterygotidae and Strobilopteridae respectively, both families within the Eurypterina. Jaekelopterus howelli shows positive allometry of the cheliceral denticles throughout ontogeny, while a number of characteristics including prosomal appendage length, carapace shape, lateral eye position, and relative breadth all vary during the growth of Strobilopterus proteus. CONCLUSIONS: The ontogeny of Strobilopterus proteus shares much in common with that of modern xiphosurans, however certain characteristics including apparent true direct development suggest a closer affinity to arachnids. The ontogenetic development of the genital appendage also supports the hypothesis that the structure is homologous to the endopods of the trunk limbs of other arthropods. Including earlier instars in the phylogenetic analysis is shown to destabilise the retrieved topology. Therefore, coding juveniles as individual taxa in an analysis is shown to be actively detrimental and alternative ways of coding ontogenetic data into phylogenetic analyses should be explored

A horseshoe crab (Arthropoda: Chelicerata: Xiphosura) from the Lower Devonian (Lochkovian) of Yunnan, China

This is the publisher's version, also available electronically from http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8826898&fileId=S0016756812000891A single specimen of a new species of the synziphosurine Kasibelinurus Pickett, 1993 is described from the Lower Devonian (Lochkovian) Xiaxishancun Formation of Yunnan Province, China. The new species, K. yueya sp. nov., extends the geographic extent of the family Kasibelinuridae from the Australian palaeocontinent to the South China palaeocontinent, and the stratigraphic range back some 50 Ma from Late to Early Devonian

Gestión de calidad bajo el enfoque de atención al cliente en las Mypes del sector servicio, colegios particulares, en el distrito de Callería, año 2017

TesisLa investigación se llevó a cabo con el objetivo de determinar la Gestión de la Calidad bajo el enfoque de atención al cliente en las mypes del sector servicios, colegios particulares, en el distrito de Calleria, año 2017. Se elaboró desarrollando una metodología de investigación del tipo descriptivo – correlacional - no experimental, donde se aplicó un cuestionario estructurado de 23 interrogantes a través de la técnica de encuesta, obteniéndose como resultados: Respecto al emprendedor: el 45% está en el rango de 40 a 50 años; en su mayoría son de género masculino; de profesión profesores. Respecto a la empresa y la formalización: las mypes encuestadas se encuentran formalizadas (85%) y el 15% no culmina sus trámites por espera de resoluciones; las mypes del sector en estudio están en el mercado de 4 a 6 años (50%) y los docentes si cumplen con una formación de acuerdo a ley (70%). Respecto de la gestión de calidad: 45% utiliza un plan de negocio y 20% está por implementar; el 60% tiene definido la misión, visión y valores de su empresa. Además, si cuentan con local propio (65%) y las instalaciones está pensado en el alumnado (70%); una minoría (40%) si recurre a cursos de capacitación; el 60% no prioriza está herramienta; demostrando que el 70% si tiene diseñado protocolos referentes al servicio de atención al cliente sin ningún tipo de discriminación, recogiendo sugerencias de los clientes que se fidelizan con el servicio brindado (90%)

Data from: From success to persistence: Identifying an evolutionary regime shift in the diverse Paleozoic aquatic arthropod group Eurypterida, driven by the Devonian biotic crisis

Mass extinctions have altered the trajectory of evolution a number of times over the Phanerozoic. During these periods of biotic upheaval a different selective regime appears to operate, although it is still unclear whether consistent survivorship rules apply across different extinction events. We compare variations in diversity and disparity across the evolutionary history of a major Paleozoic arthropod group, the Eurypterida. Using these data, we explore the group's transition from a successful, dynamic clade to a stagnant persistent lineage, pinpointing the Devonian as the period during which this evolutionary regime shift occurred. The late Devonian biotic crisis is potentially unique among the ‘Big Five’ mass extinctions in exhibiting a drop in speciation rates rather than an increase in extinction. Our study reveals eurypterids show depressed speciation rates throughout the Devonian but no abnormal peaks in extinction. Loss of morphospace occupation is random across all Paleozoic extinction events; however, differential origination during the Devonian results in a migration and subsequent stagnation of occupied morphospace. This shift appears linked to an ecological transition from euryhaline taxa to freshwater species with low morphological diversity alongside a decrease in endemism. These results demonstrate the importance of the Devonian biotic crisis in reshaping Paleozoic ecosystems

FIRST EURYPTERID FROM ITALY: A NEW SPECIES OFADELOPHTHALMUS (CHELICERATA: EURYPTERIDA) FROM THE UPPER CARBONIFEROUS OF THE CARNIC ALPS (FRIULI, NE ITALY)

The first eurypterid known from Italy is described, as Adelophthalmus piussii n. sp. It comes from the Upper Carboniferous of the Carnic Alps (Friuli, NE Italy). Relationships with related species are discussed. Adelophthalmids are the commonest eurypterids of the late Palaeozoic, at which time the disparity of the order was waning. The new record enhances our knowledge of adelophthalmid distribution and diversity

Appendix S5 - Character Weights Test NEXUS files

Zip folder containing all 100 nexus files used in the character weights tests. These matrices contain the same 4 characters (Character 56-59), generated with known rates of evolution

Appendix S6 - Character Weights

Excel spreadsheet of the weights/fits generated for our four characters in all 100 matrices for four values of k (1,3,5,10)

Appendix S1 - TNT files

Zip file containing all 100 matrices generated from our MK model of morphological change