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1. Womack, Molly Corinne. Evolution of 'earlessness' in the true Toad family (Bufonidae), The.

Degree: PhD, Biology, 2016, Colorado State University

Anurans (frogs and toads) have a tympanic middle ear to transmit airborne sound from the environment to their inner ear sensory cells. Yet, many bufonid (true toad) species have independently evolved earlessness, the lack of a tympanic middle ear, despite the importance of acoustic communication in most toad mating systems. My thesis aims to determine why middle ear structures are so evolutionarily labile in the Bufonidae family by comparing development, sensory, and morphological data of eared and earless toads within a phylogenetic context. I show that the middle ear forms very late in the development of toads and takes many months past metamorphosis to become fully functional. Adult earless species are typically less sensitive to high frequency sound and more sensitive to low frequency vibrations compared to eared toads. I also find the skulls of eared and earless are very similar, indicating the middle ear is lost without change to other developmentally or genetically linked skull features. I conclude that alternative hearing pathways allow earless species to retain some hearing sensitivity, and discuss roles for development and behavior in shaping the evolutionary lability of ear structures. Advisors/Committee Members: Hoke, Kim L. (advisor), Davies, Patricia L. (committee member), Mueller, Rachel L. (committee member), Naug, Dhurba (committee member).

Subjects/Keywords: comparative morphology; earless; sensory loss; developmental constraint; anurans; evolutionary development

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Womack, M. C. (2016). Evolution of 'earlessness' in the true Toad family (Bufonidae), The. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/178880

Chicago Manual of Style (16th Edition):

Womack, Molly Corinne. “Evolution of 'earlessness' in the true Toad family (Bufonidae), The.” 2016. Doctoral Dissertation, Colorado State University. Accessed January 16, 2021. http://hdl.handle.net/10217/178880.

MLA Handbook (7th Edition):

Womack, Molly Corinne. “Evolution of 'earlessness' in the true Toad family (Bufonidae), The.” 2016. Web. 16 Jan 2021.

Vancouver:

Womack MC. Evolution of 'earlessness' in the true Toad family (Bufonidae), The. [Internet] [Doctoral dissertation]. Colorado State University; 2016. [cited 2021 Jan 16]. Available from: http://hdl.handle.net/10217/178880.

Council of Science Editors:

Womack MC. Evolution of 'earlessness' in the true Toad family (Bufonidae), The. [Doctoral Dissertation]. Colorado State University; 2016. Available from: http://hdl.handle.net/10217/178880


University of Melbourne

2. Chaplin, Kirilee. Taxonomy, ecology and conservation genomics of North-Eastern Australian Earless Dragons (Agamidae: Tympanocryptis spp.).

Degree: 2018, University of Melbourne

Land clearing and modification of natural habitats is threatening biodiversity globally. In Australia, most native grassland habitats have been heavily modified for agriculture, including cropping and grazing. Grassland specialist species, including earless dragon lizards (Tympanocryptis spp.) in north-eastern Australia, are of conservation concern due to this continued habitat loss and fragmentation. However, the north-eastern Australian group of earless dragons (including the recently described T. condaminensis, T. wilsoni and T. pentalineata) are at significant risk, due to the presence of multiple undescribed cryptic Tympanocryptis lineages within this region. It is imperative that the taxonomy is resolved for these cryptic lineages of conservation concern, so conservation of these species may occur. One of the major challenges for taxonomists in recent times has been the species delimitation of morphologically cryptic taxa. The detection of distinct molecular lineages within cryptic genera has increased exponentially over the past decades with advances in genetic techniques. However, there are discrepancies in the rate and success of detection of cryptic taxa between studies using genetic methods and those using classic external morphology analyses. Therefore, novel integrative methods for species delimitation of cryptic taxa provide an avenue to incorporate multiple lines of evidence, including the application of osteological variation assessment where external morphological assessment fails to distinguish species. I develop a new pipeline integrating genomic data using single nucleotide polymorphisms (SNPs) and osteological geometric morphometric evidence from micro X-ray computed tomography (CT) imagery to assess variation between cryptic lineages for confident species delimitation. Here, I use this novel integrative pipeline to delimit cryptic lineages of earless dragons in north-eastern Australia. Prior to this study, there was evidence of three undescribed species of Tympanocryptis in this region. Using single mitochondrial and nuclear genes along with >8500 SNPs, I assess the evolutionary independence of the three target lineages and several closely related species. I then integrate these phylogenomic data with osteological cranial variation from CT imagery between lineages. I find that the very high levels of genomic differentiation between the three target lineages is also supported by significant osteological differences between lineages. By incorporating multiple lines of evidence for species delimitation, I provide strong support that the three cryptic lineages of Tympanocryptis in north-eastern Australia warrant taxonomic review. Earless dragons are found in most environments across the Australian continent, including a variety of ecological niches, from stony desert to tropical woodland or cracking clay savannah, although each species is often restricted to s certain habitat-type. I investigate the phylogenetic relationships among currently described earless dragons and newly delimited…

Subjects/Keywords: Integrative taxonomy; species delimitation; earless dragons; Tympanocryptis; phylogenomics; phlyogenetics; taxonomy; geometric morphometrics; Australian agamids; population structure; population genomics; species distribution modelling; conservation; ecology

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Chaplin, K. (2018). Taxonomy, ecology and conservation genomics of North-Eastern Australian Earless Dragons (Agamidae: Tympanocryptis spp.). (Doctoral Dissertation). University of Melbourne. Retrieved from http://hdl.handle.net/11343/220751

Chicago Manual of Style (16th Edition):

Chaplin, Kirilee. “Taxonomy, ecology and conservation genomics of North-Eastern Australian Earless Dragons (Agamidae: Tympanocryptis spp.).” 2018. Doctoral Dissertation, University of Melbourne. Accessed January 16, 2021. http://hdl.handle.net/11343/220751.

MLA Handbook (7th Edition):

Chaplin, Kirilee. “Taxonomy, ecology and conservation genomics of North-Eastern Australian Earless Dragons (Agamidae: Tympanocryptis spp.).” 2018. Web. 16 Jan 2021.

Vancouver:

Chaplin K. Taxonomy, ecology and conservation genomics of North-Eastern Australian Earless Dragons (Agamidae: Tympanocryptis spp.). [Internet] [Doctoral dissertation]. University of Melbourne; 2018. [cited 2021 Jan 16]. Available from: http://hdl.handle.net/11343/220751.

Council of Science Editors:

Chaplin K. Taxonomy, ecology and conservation genomics of North-Eastern Australian Earless Dragons (Agamidae: Tympanocryptis spp.). [Doctoral Dissertation]. University of Melbourne; 2018. Available from: http://hdl.handle.net/11343/220751

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