H. Shaffer

Publications122
h-index54
Citations9,467
Highly Influential Citations692
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Annual review of ecology, evolution, and systematics
TLDR
Twenty-four articles by biologists, ecologists, and other scientists represent a year's progress in the field of paleobiogeography, genetics and geographic structure, and time as an ecological resource are addressed.
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Phylogenetic hypotheses for the turtle family Geoemydidae.
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Tests of turtle phylogeny: molecular, morphological, and paleontological approaches.
TLDR
Branch-length analysis and independent dates from the fossil record suggest that these unresolved nodes may represent a rapid radiation of the major cryptodiran lineages 90-120 million years ago.
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Assessing Concordance of Fossil Calibration Points in Molecular Clock Studies: An Example Using Turtles
TLDR
A new cross‐validation method is presented that identifies inconsistent fossils when multiple fossil calibrations are available for a clade and it is found that despite their overall antiquity as a lineage, the most species‐rich clades of turtles diversified well within the Cenozoic.
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Spatial Tests of the Pesticide Drift, Habitat Destruction, UV‐B, and Climate‐Change Hypotheses for California Amphibian Declines
TLDR
In four species, a strong positive association between declines and the amount of upwind agricultural land use is found, suggesting that wind-borne pesticides may be an im- portant factor in declines.
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THE POLYTYPIC SPECIES REVISITED: GENETIC DIFFERENTIATION AND MOLECULAR PHYLOGENETICS OF THE TIGER SALAMANDER AMBYSTOMA TIGRINUM (AMPHIBIA: CAUDATA) COMPLEX
TLDR
A phylogenetic analysis of the Ambystoma tigrinum complex is presented, based on approximately 840 base pairs of mitochondrial‐DNA sequence from the rapidly evolving D‐loop and an adjacent intron, which suggests that these eight lineages diverged during a period of rapid cladogenesis.
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Molecular phylogenetics and evolution of turtles.
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Multiple data sets, high homoplasy, and the phylogeny of softshell turtles (Testudines: Trionychidae).
TLDR
A strong estimate of the phylogeny of softshell turtles is used as the basis for a novel rank-free classification, and strategies for analyzing highly homoplasious mtDNA data in deep phylogenetic problems where increased taxon sampling is not an option are examined.
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Troubleshooting Molecular Phylogenetic Analyses
TLDR
This review focuses on several persistent problems, including rooting, conflict among data sets, weak support in trees, strong but evidently incorrect support, and the computational issues arising when methods are applied to the large data sets that are becoming increasingly commonplace.
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Turtle phylogeny: insights from a novel nuclear intron.
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