Geometric morphometrics of the Eastern newt's limbs across polyphenic life stages

Location

D.P. Culp Center Room 303

Start Date

4-5-2024 2:30 PM

End Date

4-5-2024 3:30 PM

Name of Project's Faculty Sponsor

Richard Carter

Faculty Sponsor's Department

Biological Sciences

Competition Type

Competitive

Type

Oral Presentation

Presentation Category

Science, Technology and Engineering

Abstract or Artist's Statement

Eastern newts (Notophthalmus viridescens) are a ubiquitous member of eastern North America’s caudate fauna. Unlike the common amphibian with two major life stages, their life cycle is typically split into three phases, commonly called a triphasic life cycle. The larvae of eastern newts are fully aquatic, eventually metamorphosing into terrestrial juveniles called efts. Upon sexual maturity, the eft will metamorphose into a semi-aquatic adult whose external morphology resembles other aquatic salamander species. The eastern newt is considered polyphenic and possesses alternative life cycle strategies that are not as common, including an aquatic juvenile stage and a facultatively paedomorphic adult stage. Since the different life stages of these salamanders occupy different ecological niches (terrestrial vs. semi-aquatic vs. fully aquatic) throughout their lives and, therefore likely experience various physical forces on their skeletons, they provide a unique model to study musculoskeletal changes across ontogeny and ecology. We hypothesize that ontogenetic niche shifts and the associated shifts in locomotion biomechanics will coincide with shifts in the morphology of limbs. Using micro-computed tomography (µCT) and geometric morphometrics (GMM), we quantified shape changes of limb bones across different life stages (terrestrial juvenile, aquatic juvenile, paedomorph, adult). Our findings indicate a correlation between the form and function of specific bones in the limbs, with ecological differences and the associated biomechanics being the main contributors to these variances.

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Apr 5th, 2:30 PM Apr 5th, 3:30 PM

Geometric morphometrics of the Eastern newt's limbs across polyphenic life stages

D.P. Culp Center Room 303

Eastern newts (Notophthalmus viridescens) are a ubiquitous member of eastern North America’s caudate fauna. Unlike the common amphibian with two major life stages, their life cycle is typically split into three phases, commonly called a triphasic life cycle. The larvae of eastern newts are fully aquatic, eventually metamorphosing into terrestrial juveniles called efts. Upon sexual maturity, the eft will metamorphose into a semi-aquatic adult whose external morphology resembles other aquatic salamander species. The eastern newt is considered polyphenic and possesses alternative life cycle strategies that are not as common, including an aquatic juvenile stage and a facultatively paedomorphic adult stage. Since the different life stages of these salamanders occupy different ecological niches (terrestrial vs. semi-aquatic vs. fully aquatic) throughout their lives and, therefore likely experience various physical forces on their skeletons, they provide a unique model to study musculoskeletal changes across ontogeny and ecology. We hypothesize that ontogenetic niche shifts and the associated shifts in locomotion biomechanics will coincide with shifts in the morphology of limbs. Using micro-computed tomography (µCT) and geometric morphometrics (GMM), we quantified shape changes of limb bones across different life stages (terrestrial juvenile, aquatic juvenile, paedomorph, adult). Our findings indicate a correlation between the form and function of specific bones in the limbs, with ecological differences and the associated biomechanics being the main contributors to these variances.