Abstract Detail

Systematics

Castillo, Gabriela [1], Sarazen, Jill [1], Moore, Michael [2].

Using Molecular Phylogenetics to Uncover Cryptic Species Within Tiquilia palmeri.

Tiquilia (Ehretiaceae) is a relatively old genus (originating ~30 million years ago) comprising approximately 30 species of herbs and small shrubs, all of which can be found in the desert regions of North and South America. Tiquilia palmeri (part of subgenus Tiquilia) grows in the Sonoran Desert and has been found to be variable in its growth form, flower color, and sepals. An earlier study of the evolutionary history of Tiquilia demonstrated the surprising presence of two distinct groups of T. palmeri populations in Arizona and California that may represent undescribed species. However, this study did not include any populations from Mexico. We aim to test whether these truly are undescribed species and to understand the evolutionary history of T. palmeri more completely by including Mexican populations. To explore this, we isolated DNA from herbarium specimens of 38 populations of T. palmeri growing throughout its range. We then sequenced the DNA of the nuclear ITS region and the chloroplast rps16 region. While all populations of T. palmeri formed a single clade in the resulting phylogenetic trees, there was far more diversity than originally expected. At least four relatively deep clades were detected in both the ITS and plastid trees, and in some cases these clades are readily distinguishable by differences in calyx morphology and habit. These clades are also largely allopatric. This suggests that what has been considered to be T. palmeri is actually several species that have gone unrecognized until now. 

1 - Oberlin College, Department of Biology, 119 Woodland Street, Oberlin, OH, 44074, USA
2 - Oberlin College, Department Of Biology, 119 Woodland St., Science Center K111, Oberlin, OH, 44074, United States

Keywords:
Boraginaceae
cryptic species
Mexico
Sonoran Desert
phylogeny.

Presentation Type: Poster
Session: P, Systematics Posters
Location: Virtual/Virtual
Date: Thursday, July 30th, 2020
Time: 5:00 PM Time and date to be determined
Number: PSY008
Abstract ID:295
Candidate for Awards:None