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Cornell University
CURRENT PROJECTS
Tetrapod Forelimb Evolution
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Tetrapods have evolved into a wide variety of niches, with many of these niches requiring substantial remodeling of the forelimb (e.g., flying in bats, digging in moles). We are studying the internal morphology of forelimbs using cross-sectional geometry analyses and external morphology using 3D geometric morphometrics to better understand convergence in avian and mammalian forelimb structure and the coupling and decoupling of rates of morphological evolution in the forelimb and rates of speciation and extinction.
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This work has demonstrated numerous insights including that small mammals do not require major reorganizations of their proximal limb to move into novel niches, bird wings are more integrated at higher body masses to accommodate increased biomechanical pressures, bats and birds have evolved divergent patterns of limb integration, and mammal forelimb disparity increases with increasing body mass.
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Links:
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Hedrick et al. (2020) Scientific Reports
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Hedrick et al., 2022; Anatomical Record
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Orkney and Hedrick, 2024; Nat Comm
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Orkney et al., 2025; Nature E&E
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Bat Sensory Ecology and Morphometry
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We are studying (1) the variability of skull shape and its relationship with dietary ecology in New World leaf-nosed bats and (2) the relationship between sensory morphometry (e.g. eye globe size, olfactory bulb size) as analyzed with diffusible contrast-enhanced iodine staining, dietary ecology, and skull shape in New World Leaf Nosed Bats.
This work is in collaboration with a broad network of researchers from Stony Brook, UC Merced, UCLA, and the Queen Mary University of London,
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Links:
Hedrick et al. (2018) Microscopy and Microanalysis
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Hedrick and Dumont (2018) JMamm
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Hedrick et al. (2020) JMammEvol
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Amphibian Movement Ecology and Climate Change
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Amphibians are a critical component in forest ecosystems. I am a member of SPARCnet (Salamander Population Adaptation Research Collaboration Network) studying the behavior of the red-backed salamander throughout its range and the potential effects on this salamander species as a result of climate change.
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This research is being conducted at both the macroclimatic scale (using methods such as fuzzy logic and species distribution modeling) as well as at the microclimatic scale (using spatial capture-recapture).
We are also broadly interested in how amphibians respond to other anthropogenic factors such as urbanization and roads.
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Links:
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Hedrick et al. (2019) JUrban Ecology
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Hedrick et al. (2021) Herp Review
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Taphonomic Distortion and its Effects on Shape​
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Fossils all undergo some degree of taphonomic distortion as a result of normal fossilization processes. However, this distortion means that the fossils studied by paleontologists are not the same shape that the fossil taxon had in life, complicating biological interpretations. Using a range of modern and fossil taxa, we have quantified the magnitude of asymmetric distortion in fossils.
We are currently working to develop corrections to the issue of taphonomic distortion through a combination of field and modeling studies.
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Links:
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Hedrick and Dodson (2013) PLoS One
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Hedrick et al. (2019) Paleobiology
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Female Genital Morphology and Sexual Selection ​
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Genitals are among the most variable in nature and their morphological variation is linked to both natural selection and sexual selection. Further, male and female genitalia often evolve under evolutionary arms races. While male genitalia has been extensively studied for many decades across a wide variety of taxonomic groups, female genitalia is understudied.
We are working to better understand the selective pressures under which female genitalia have evolved and how female morphology relates to male genitalia using 3D imaging and shape analyses (Shark vaginas in 2D and 3D on left).
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Links:
Hedrick et al., 2019; JZoology
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Orbach et al., 2018; Evolution
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Orbach et al., 2020; Scientific Reports
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