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Avalonia – A dismembered Cambrian continent

Paradoxides (signature taxon of the Avalonian Faunal Province). Avalonia – A dismembered Cambrian continent. Jurassic Period (180 Ma). Jaccard Index (M/M+N) Most similar: W and St Least similar: So and BC Dice Index 2M/(2M+N) Most similar: W and St Least similar: So and BC.

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Avalonia – A dismembered Cambrian continent

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  1. Paradoxides (signature taxon of the Avalonian Faunal Province) Avalonia – A dismembered Cambrian continent

  2. Jurassic Period (180 Ma)

  3. Jaccard Index(M/M+N)Most similar: W and StLeast similar: So and BCDice Index2M/(2M+N)Most similar: W and StLeast similar: So and BC

  4. Raup-Crick IndexMost similar: St and SoLeast similar: W and BC(So different indices yield different results – they are not statistical tests)Simpson IndexMost similar: 4 tied at 1.00(Sensitivity Issues)Least similar: So and BC

  5. Jaccard & Dice IndicesW and St are most similar H0 = W and St in close proximity?(Perhaps, but lifestyle?)According to three of the four IndicesSo and BC are least similarH0 = So and BC widely separated?(Whoa! When was the Sonoman Orogeny? Maybe latitude and/or a mountain chain are more plausible.)

  6. Taylor (2006)

  7. Base of the Ptychaspid Biomere

  8. Taylor (2006)

  9. Lower Ordovician Trilobite Faunas (Loch, 2007)

  10. Lower Ordovician (Upper Ibexian) trilobite faunas Jaccard Index values for species data from nine locations in Laurentian North America

  11. Factors affecting the index: 1. Taxonomy: lower grade, lower values; accuracy? 2. Relative Sample Size (AL/MT vs. UT; TX vs. OK) 3. Stratigraphic precision/accuracy (same age?) 4. Real differences in composition (environment)

  12. Utility of fossils for establishing and testing hypothesesFor establishing: Ho = Sonomia had not yet docked by Pliensbachian Age(based on minimal similarity of So and BC in Jaccard & Dice Indices)For testing:Ho = Precordillera Terrane in Argentina is Perigondwanan (not Laurentian)

  13. Origin of the Argentine Precordillera: Laurentian vs. Peri-Gondwanan

  14. Clelandia texana Clelandia parabola

  15. Plethopeltis stitti

  16. Plethopeltis new species

  17. Chapmania taylori

  18. Heymonsicambria taylori

  19. Chapmania taylori

  20. “Plethopeltis lochi”

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