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Cryptic species delimitation in the southern Appalachian Antrodiaetus unicolor (Araneae: Antrodiaetidae) species complex using a 3RAD approach
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  • Lacie Newton,
  • James Starrett,
  • Brent Hendrixson,
  • Shahan Derkarabetian,
  • Jason Bond
Lacie Newton
University of California Davis
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James Starrett
University of California Davis
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Brent Hendrixson
Millsaps College
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Shahan Derkarabetian
Harvard University
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Jason Bond
UC Davis
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Abstract

Although species delimitation can be highly contentious, the development of reliable methods to accurately ascertain species boundaries is an imperative step in cataloguing and describing Earth’s quickly disappearing biodiversity. Spider species delimitation remains largely based on morphological characters; however, many mygalomorph spider populations are morphologically indistinguishable from each other yet have considerable molecular divergence. The focus of our study, Antrodiaetus unicolor species complex which contains two sympatric species, exhibits this pattern of relative morphological stasis with considerable genetic divergence across its distribution. A past study using two molecular markers, COI and 28S, revealed that A. unicolor is paraphyletic with respect to A. microunicolor. To better investigate species boundaries in the complex, we implement the cohesion species concept and employ multiple lines of evidence for testing genetic exchangeability and ecological interchangeability. Our integrative approach includes extensively sampling homologous loci across the genome using a RADseq approach (3RAD), assessing population structure across their geographic range using multiple genetic clustering analyses that include STRUCTURE, PCA, and a recently developed unsupervised machine learning approach (Variational Autoencoder). We evaluate ecological similarity by using large-scale ecological data for niche-based distribution modeling. Based on our analyses, we conclude that this complex has at least one additional species as well as confirm species delimitations based on previous less comprehensive approaches. Our study demonstrates the efficacy of genomic-scale data for recognizing cryptic species, suggesting that species delimitation with one data type, whether one mitochondrial gene or morphology, may underestimate true species diversity in morphologically homogenous taxa with low vagility.

Peer review status:ACCEPTED

20 Feb 2020Submitted to Molecular Ecology
21 Feb 2020Submission Checks Completed
21 Feb 2020Assigned to Editor
08 Mar 2020Reviewer(s) Assigned
10 Apr 2020Review(s) Completed, Editorial Evaluation Pending
15 Apr 2020Editorial Decision: Revise Minor
14 May 2020Review(s) Completed, Editorial Evaluation Pending
14 May 20201st Revision Received
18 May 2020Editorial Decision: Accept