TY - JOUR
T1 - Integrating phylogeography and high-resolution X-ray CT reveals five new cryptic species and multiple hybrid zones among Australian earless dragons
AU - Chaplin, Kirilee
AU - Hipsley, Christy A.
AU - Sarre, Stephen D.
AU - Sumner, Joanna
AU - Hutchinson, Mark
N1 - Funding Information:
Research support for this project was provided by the Department of Environment and Planning, ACT Government. C.H. is supported by an ARC DECRA (grant no. DE180100629).
Funding Information:
Ethics. All samples used in this study were tissue samples held in museum collections. Data accessibility. Additional text and data can be found in the electronic supplementary material. mtDNA sequences are available from Genbank, with accession numbers provided in electronic supplementary material, table S1. The mtDNA alignment, micro-CT cranial mesh files (PLY format) and landmark files are available in the Figshare digital repository and can be accessed at: https://doi.org/10.26188/5dbf56752bf10. Authors’ contributions. All authors contributed to analysis and interpretation of data and drafting of the manuscript. J.M., M.H., J.S. and S.D.S. contributed to study design and concept. K.C. collected external morphology data and CT scans; K.C. and J.S. undertook genetic analyses; K.C. and C.A.H. undertook morphological and geometric morphometric analyses. J.M., C.A.H., M.H. and K.C. wrote the paper. Competing interests. We declare we have no competing interests. Funding. Research support for this project was provided by the Department of Environment and Planning, ACT Government. C.H. is supported by an ARC DECRA (grant no. DE180100629). Acknowledgements. We thank W. Osborne, T. McGrath and P. Robertson for their expertise and advice. Thank you to J. Black for technical support with micro X-ray CT scanning at the School of Earth Sciences, University of Melbourne. S.D.S. acknowledges the support of the Australian Research Council LP110200029.
Publisher Copyright:
© 2019 The Authors. Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited.
PY - 2019/12/1
Y1 - 2019/12/1
N2 - Cryptic lineages, comprising species complexes with deep genetic structuring across the landscape but without distinct morphological differences, impose substantial difficulties for systematists and taxonomists in determining true species diversity. Here, we present an integrative approach that combines data from phylogeography and geometric morphometric analyses of three-dimensional cranial models to revisit the uncertain taxonomy of earless dragons from southern and central Australia that at one time or another have been included under the name Tympanocryptis lineata. Our approach finds strong support for seven previously described species, and more importantly, five undescribed Tympanocryptis taxa for which we provide a taxonomic treatment. We also find evidence of introgression and hybridization in three discrete contact zones between lineages, supported by mitochondrial and nuclear genes, as well as morphological analyses. With a sampling design that includes at least five individuals for each genetic lineage with corresponding X-ray microcomputed tomography scans, we perform comparative evolutionary analyses to show that there is a significant phylogenetic signal in Tympanocryptis cranial shape. Our results demonstrate the importance of using multiple specimens in each genetic lineage, particularly in cases of potential hybridization, and that geometric morphometrics, when used in an integrative framework, is a powerful tool in species delimitation across cryptic lineages. Our results lay the groundwork for future evolutionary studies in this widespread group across multiple environmental types and identify several species of immediate conservation concern with a focus on T. petersi sp. nov. We suggest that this species has undergone significant population declines and warrants a full conservation assessment.
AB - Cryptic lineages, comprising species complexes with deep genetic structuring across the landscape but without distinct morphological differences, impose substantial difficulties for systematists and taxonomists in determining true species diversity. Here, we present an integrative approach that combines data from phylogeography and geometric morphometric analyses of three-dimensional cranial models to revisit the uncertain taxonomy of earless dragons from southern and central Australia that at one time or another have been included under the name Tympanocryptis lineata. Our approach finds strong support for seven previously described species, and more importantly, five undescribed Tympanocryptis taxa for which we provide a taxonomic treatment. We also find evidence of introgression and hybridization in three discrete contact zones between lineages, supported by mitochondrial and nuclear genes, as well as morphological analyses. With a sampling design that includes at least five individuals for each genetic lineage with corresponding X-ray microcomputed tomography scans, we perform comparative evolutionary analyses to show that there is a significant phylogenetic signal in Tympanocryptis cranial shape. Our results demonstrate the importance of using multiple specimens in each genetic lineage, particularly in cases of potential hybridization, and that geometric morphometrics, when used in an integrative framework, is a powerful tool in species delimitation across cryptic lineages. Our results lay the groundwork for future evolutionary studies in this widespread group across multiple environmental types and identify several species of immediate conservation concern with a focus on T. petersi sp. nov. We suggest that this species has undergone significant population declines and warrants a full conservation assessment.
KW - Conservation management
KW - CT scanning
KW - Geometric morphometrics
KW - Integrative taxonomy
KW - Species delimitation
KW - Tympanocryptis
UR - http://www.scopus.com/inward/record.url?scp=85077400189&partnerID=8YFLogxK
U2 - 10.1098/rsos.191166
DO - 10.1098/rsos.191166
M3 - Article
C2 - 31903207
AN - SCOPUS:85077400189
SN - 2054-5703
VL - 6
SP - 1
EP - 32
JO - Royal Society Open Science
JF - Royal Society Open Science
IS - 12
M1 - 191166
ER -