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Full-Text Articles in Physical Sciences and Mathematics

The Digital Atlas Of Ancient Life: Delivering Information On Paleontology And Biogeography, Jonathan R. Hendricks, Alycia L. Stigall, Bruce S. Lieberman Jul 2015

The Digital Atlas Of Ancient Life: Delivering Information On Paleontology And Biogeography, Jonathan R. Hendricks, Alycia L. Stigall, Bruce S. Lieberman

Jonathan R. Hendricks

No abstract provided.


Glowing Seashells: Diversity Of Fossilized Coloration Patterns On Coral Reef-Associated Cone Snail (Gastropoda: Conidae) Shells From The Neogene Of The Dominican Republic, Jonathan R. Hendricks Apr 2015

Glowing Seashells: Diversity Of Fossilized Coloration Patterns On Coral Reef-Associated Cone Snail (Gastropoda: Conidae) Shells From The Neogene Of The Dominican Republic, Jonathan R. Hendricks

Jonathan R. Hendricks

The biology of modern Conidae (cone snails)—which includes the hyperdiverse genus Conus—has been intensively studied, but the fossil record of the clade remains poorly understood, particularly within an evolutionary framework. Here, ultraviolet light is used to reveal and characterize the original shell coloration patterns of 28 species of cone snails from three Neogene coral reef-associated deposits from the Cibao Valley, northern Dominican Republic. These fossils come from the upper Miocene Cercado Fm. and lower Pliocene Gurabo Fm., and range in age from about 6.6-4.8 Ma. Comparison of the revealed coloration patterns with those of extant species allow the taxa to …


Using Marine Snails To Teach Biogeography And Macroevolution: The Role Of Larvae And Dispersal Ability In The Evolution And Persistence Of Species, Jonathan R. Hendricks Apr 2012

Using Marine Snails To Teach Biogeography And Macroevolution: The Role Of Larvae And Dispersal Ability In The Evolution And Persistence Of Species, Jonathan R. Hendricks

Jonathan R. Hendricks

While some marine animals are capable of traveling great distances, many have limited mobility as adults and spend the majority of their lifetimes in a small geographical area or may even be cemented to a single place. While it might be expected that species with limited mobility would have small geographic distributions, some nevertheless occur over very large areas. This is the case for some marine snails (gastropods). A key factor that impacts the geographic distribution of marine snails is the type of larvae they have during the phase of their life history that follows hatching from an egg. Because …


W(H)Ither Fossils? Studying Morphological Character Evolution In The Age Of Molecular Sequences, Elizabeth J. Hermsen, Jonathan R. Hendricks Mar 2008

W(H)Ither Fossils? Studying Morphological Character Evolution In The Age Of Molecular Sequences, Elizabeth J. Hermsen, Jonathan R. Hendricks

Jonathan R. Hendricks

A major challenge in the post-genomics era will be to integrate molecular sequence data from extant organisms with morphological data from fossil and extant taxa into a single, coherent picture of phylogenetic relationships; only then will these phylogenetic hypotheses be effectively applied to the study of morphological character evolution. At least two analytical approaches to solving this problem have been utilized: (1) simultaneous analysis of molecular sequence and morphological data with fossil taxa included as terminals in the analysis, and (2) the molecular scaffold approach, in which morphological data are analyzed over a molecular backbone (with constraints that force extant …


Exceptionally Preserved Jellyfishes From The Middle Cambrian, Paulyn Cartwright, Susan L. Halgedahl, Jonathan R. Hendricks, Richard D. Jarrard, Antonio C. Marques, Allen G. Collins, Bruce S. Lieberman Oct 2007

Exceptionally Preserved Jellyfishes From The Middle Cambrian, Paulyn Cartwright, Susan L. Halgedahl, Jonathan R. Hendricks, Richard D. Jarrard, Antonio C. Marques, Allen G. Collins, Bruce S. Lieberman

Jonathan R. Hendricks

Cnidarians represent an early diverging animal group and thus insight into their origin and diversification is key to understanding metazoan evolution. Further, cnidarian jellyfish comprise an important component of modern marine planktonic ecosystems. Here we report on exceptionally preserved cnidarian jellyfish fossils from the Middle Cambrian (~505 million years old) Marjum Formation of Utah. These are the first described Cambrian jellyfish fossils to display exquisite preservation of soft part anatomy including detailed features of structures interpreted as trailing tentacles and subumbrellar and exumbrellar surfaces. If the interpretation of these preserved characters is correct, their presence is diagnostic of modern jellyfish …


Biogeography And The Cambrian Radiation Of Arachnomorph Arthropods, Jonathan R. Hendricks, Bruce S. Lieberman Jan 2007

Biogeography And The Cambrian Radiation Of Arachnomorph Arthropods, Jonathan R. Hendricks, Bruce S. Lieberman

Jonathan R. Hendricks

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. …