Abstract Detail

Biogeography

Hooker, Marcus [1], Hufford, Larry [2].

Evolution of the paleo-endemic sister species Synthyris platycarpa and S. schizantha (Plantaginaceae) in the Pacific Northwest.

Range fragmentation has been implicated in the origin of paleoendemics. In the Pacific Northwest, the Cascade orogeny, which led to aridification of the inland Northwest beginning around 2-3 mya, has been implicated in species range disjunctions and vicariant speciation. The sister species Synthyris schizantha and S. platycarpa are geographically restricted endemic species known from few populations with S. schizantha located in the Cascade and Olympic Mountains of Washington and coastal range of Oregon and S. platycarpa located in the Northern Rocky Mountains of Idaho. Great similarities in morphology and habitat between the two species have been noted since the discovery of S. platycarpa; these similarities may be due to phylogenetic niche conservatism, but as the Northern Rocky Mountains are drier than areas in and west of the Cascade Mountains, a niche shift in S. platycarpa to drier climates may be possible. Our phylogenetic divergence time estimation for the genus shows these species diverged approximately 3 mya, a time consistent with vicariant speciation mediated by the Cascade Mountains orogeny. We test whether the spatial distribution of genetic diversity in this species pair indicates whether each species harbors relatively high genetic diversity refugial populations or whether the vicariance and population restrictions have resulted in a demographic bottleneck. Preliminary results show these species to be highly divergent genetically but with exceptionally low intraspecific genetic diversity, possibly due to a bottleneck event. Ecological niche modeling more closely reconstructs the fragmented distribution of S. platycarpa but it over predicts the range of S. schizantha, which indicates factors other than climate restrict its distribution. As ENM results also differentiate between the niches of the two species, the degree of niche conservatism between them may not be particularly strong and the drier climate of the northern Rocky Mountains may have lead to a niche shift for Synthyris platycarpa.

1 - Washington State University, School of Biological Sciences, PO Box 644236, Pullman, WA, 99164, USA
2 - Washington State University, SCHOOL OF BIOLOGICAL SCIENCES, 312 Abelson Hall, PULLMAN, WA, 99164-4236, USA

Keywords:
phylogeography
biogeography
Plantaginaceae
glaciation
Pacific Northwest.

Presentation Type: Poster
Session: P, Biogeography
Location: Exhibit Hall/Omni Hotel
Date: Monday, June 26th, 2017
Time: 5:30 PM This poster will be presented at 5:30 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PBG005
Abstract ID:434
Candidate for Awards:None