UC Davis doctoral alumna Lacie Newton, formerly of the Jason Bond lab and now a postdoctoral fellow in the Jessica Ware lab,  American Museum of Natural History (AMNH), New York City, is the lead author of a newly published article on three sibling trapdoor spiders, Aptostichus barackobamai,  A. isabella, and A. icenoglei.

Her major professor Jason Bond, then a professor and administrator at Auburn University, Alabama,  described and named what is commonly called "The Barack Obama Trapdoor Spider" in 2012. 

The article, published in the journal Ecology and Evolution and part of Newton's 2022 doctoral dissertation, is titled "Phylogeography and Cohesion Species Delimitation of California Endemic Trapdoor Spiders within the Aptostichus icenoglei Sibling Species Complex (Araneae: Mygalomorphae: Euctenizidae)."

Co-authors are Professor Bond, who is the Evert and Marion Schlinger Endowed Chair in the UC Davis Department of Entomology and Nematology, and associate dean, College of Agricultural and Environmental Sciences; and Bond lab members, project scientist James Starrett and doctoral candidate Emma Jochim.

"Species delimitation in mygalomorph spiders using only traditional morphological approaches has underestimated species diversity," Newton said, "yet molecular approaches have been shown to overestimate species diversity due to the local population structuring seen as 'species divergence.' Specifically, the Aptostichus icenoglei complex, which comprises the three sibling species, A. barackobamai,  A. isabella, and A. icenoglei, exhibits evidence of cryptic mitochondrial DNA diversity throughout their ranges across the California Floristic Province."

"Our study, using an integrative cohesion-species based delimitation approach, evaluated genetic exchangeability using genomic-scale data (that is, ultraconserved elements, UCEs) and then ecological exchangeability with large scale ecological data," Newton said. "Considering the lack of congruence across data types and analyses, we take a more conservative approach by retaining species boundaries within A. icenoglei."

The researchers sampled 62 individuals overall for the three species within the complex, using both specimens from Bond (2012) and new records. "A. barackobamai was collected across its geographic range in northern California for a total of 21 samples, and A. icenoglei was collected throughout its range in southern California for a total of 40 samples," they wrote. "Only one specimen of A. isabella was included in this study due to collecting constraints (i.e., only one individual of this species has ever been collected and a burrow has not yet been found containing this species; Bond, (2012)

Next steps? "We hope to use whole genomes for both reconstructing evolutionary relationships as well as identifying genes that contribute to potential adaptive divergence across the landscape," Newton said. "We also hope to gather more natural history data for each of the species, especially A. icenoglei populations, for general ecological information that may aid in species delimitation." 

Born and raised in Eupora, Miss., and a first-generation college student in her family, Lacie holds a bachelor of science degree in biological sciences (2016) from Millsaps College, Jackson, Miss. She then enrolled in the graduate school program at Auburn University, studying with Professor Bond. When he accepted the Schlinger Endowed Chair in 2018, Lacie, along with other lab members, transferred to UC Davis. Newton completed her dissertation on species delimitation in two trapdoor spider groups, Antrodiaetus unicolor complex and Aptostichus icenoglei sister species complex, and evaluation of interspecific relationships within the genus Aptostichus. 

The research drew support from a National Science Foundation Grant awarded to Bond and Starrett; the McBeth Memorial Scholarship awarded to Newton; and the Evert and Marion Schlinger Foundation.