Abstract Detail

Biogeography

Brindley, Josh [1], Roalson, Eric [2], Hufford, Larry [3].

Phylogeny, Historical Biogeography, and Divergence Time Estimates of Eucnide (Loasaceae).

Eucnide (Loasaceae) is a small genus of flowering plants consisting of about 16 species. Eucnide is distributed across Mexico, Guatemala, and the American Southwest, a geographically complex landscape made up of floristically unique deserts, large mountain ranges, and a large, geographically isolated peninsula. This complex geography is credited for high levels of biodiversity and endemism in the region. Floral morphology within Eucnide is wildly variable with a wide range of corolla size, color, and architecture. In the most recent treatment of the genus, Thompson and Ernest (1967) recognize three sections of Eucnide, differentiated based on floral morphology. A previous study used morphology to estimate the phylogenetic relationships within the genus (Hufford 1988), but to date, no molecular phylogenetic studies have broadly sampled species in this genus. We used Bayesian and maximum-likelihood phylogenetic analyses of one plastid marker (matK) and one nuclear marker (ITS) to: 1) test the monophyly of Eucnide sections as described by Thompson and Ernst (1967) and assess whether the existing taxonomy sufficiently explains diversity within the genus. 2) Assess the divergence times of Eucnide lineages to determine when the major clades diverged. 3) Estimate the ancestral area of Eucnide and hypothesize patterns of geographical diversification of the genus. We found that not all the sections of Eucnide are monophyletic and the subgeneric taxonomy needs revision. Additionally, the major clades of Eucnide are predominantly restricted to geographic regions, suggesting that species have frequently diversified within geographic areas. The ancestral area of Eucnide was inferred to be widespread, and the divergence times of the major clades coincide with major geological events, particularly, the formation of the North American warm deserts, the isolation of the Baja Peninsula, and the uplift of the Trans-Volcanic Mexican Belt. This suggests that major geological/climatic events may have contributed to the diversification of the genus.

1 - 605 NW Fisk St. Trlr. 45, Pullman, WA, 99163, United States
2 - Washington State University, School Of Biological Sciences, Abelson Hall 339, Pullman, WA, 99164, United States
3 - Washington State University, School Of Biological Sciences, Pullman, WA, 99164, United States

Keywords:
biogeography
desert
Loasaceae
Eucnide
systematics.

Presentation Type: Oral Paper
Session: BIOG1, Biogeography I
Location: Tucson E/Starr Pass
Date: Monday, July 29th, 2019
Time: 8:00 AM
Number: BIOG1001
Abstract ID:84
Candidate for Awards:None