Abstract Detail



Systematics

Feng, Keyi [1], Garnett, Sydney [1], Douglas, Norman [2], Flores Olvera, Hilda [3], Ochoterena, Helga [3], Moore, Michael J. [4].

Disentangling the gypsum endemic Mentzelias of the northern Chihuahuan Desert.

Adapted to nutrient-poor conditions, gypsum endemic plants form an important part of the Chihuahuan Desert flora. Ongoing work in our lab has demonstrated that dominant gypsum endemic taxa in the Chihuahuan Desert typically belong to clades of endemics that have speciated allopatrically into typically well-marked species. However, the three gypsum endemic Mentzelia (Loasaceae) species of New Mexico and west Texas present somewhat confusing morphological diversity across their geographic ranges. Schenk and Hufford found these species were early-diverging members of Mentzelia sect. Bartonia, but the taxa were not resolved into a single clade. Likewise, at least one of the gypsum endemic species (M. humilis) was not monophyletic, although support and resolution were not uniformly high. To further test the species boundaries of these gypsum endemic Mentzelias, and to explore phylogeographic variation and patterns of morphological variation among populations, we sequenced four regions (nuclear ITS and ETS, and the plastid ndhF/rpl32 and rpl32/trnL spacer regions) for multiple populations of all three endemic Mentzelia species in New Mexico and west Texas. For most populations, we sequenced a minimum of 10 individuals. Our sequence data reveal a substantial amount of geographic variation and structure among populations, particularly within nuclear data. We find increased support for the non-monophyly of Mentzelia humilis, with populations from the Upper Pecos River valley forming a clade distinct from the populations in southern New Mexico and west Texas. These two clades may best be treated as distinct taxa. Populations of M. perennis were resolved into several clades with morphological and geographical coherence. Populations of M. perennis from central New Mexico that possess unlobed to weakly lobed leaves grouped more closely with the similarly unlobed M. todiltoensis from northern New Mexico.


Related Links:
The Origin and Evolution of Gypsum Endemic Plants


1 - Oberlin College, 119 Woodland St., Oberlin, OH, 44074, USA
2 - University Of Florida, Biology, PO Box 118525, Gainesville, FL, 32611, United States
3 - Instituto de BiologĂ­a, UNAM, Apartado Postal 70-367, Mexico, DF, 04510, Mexico
4 - Oberlin College, Department Of Biology, 119 Woodland St., Science Center K111, Oberlin, OH, 44074, United States

Keywords:
Mentzelia
Loasaceae
gypsum
New Mexico
Texas
Chihuahuan Desert
Biogeography.

Presentation Type: Poster
Number: PSY009
Abstract ID:434
Candidate for Awards:None


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