Abstract Detail

Systematics

Castillo, Gabriela [1], Sarazen, Jillian [2], Moore, Michael [3].

Using Molecular and Morphological Data to Uncover Cryptic Species Within Tiquilia palmeri.

Tiquilia (Ehretiaceae) is comprised of 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 45 populations of T. palmeri growing throughout its range. We then sequenced the DNA of the nuclear ITS region and the chloroplast rps16 region and reconstructed a phylogenetic tree showing the relationships among populations of T. palmeri. The resulting trees showed far more diversity than originally expected. We found that within T. palmeri, there are at least 4 clades subtended by relatively long branches that correspond to largely allopatric population groups, meaning that what has been considered to be T. palmeri is actually several species that have gone unrecognized until now. We have gathered morphometric data for these populations to test whether morphological differences exist among these clades. Thus far, we have determined that there is variation in the sepal lengths among these clades as one clade has very short sepals, one has medium sepals, and a third has very long sepals. We also are working to collect data regarding several other characters such as nutlet size and leaf length and width.

1 - Oberlin College, Department of Biology, 119 Woodland Street, Oberlin, OH, 44074, United States
2 - University of Vermont, Rubenstein School of Environment and Natural Resources, 81 Carrigan Drive, Burlington, VT, 05405, USA
3 - Oberlin College, Department Of Biology, 119 Woodland St., Science Center K111, Oberlin, OH, 44074, United States

Keywords:
Tiquilia
systematics
morphometric analyses
Boraginales
Ehretiaceae
Cryptic Species
Sonoran Desert.

Presentation Type: Poster
Number: PSY004
Abstract ID:346
Candidate for Awards:None