Cryptic Speciation in the Caesalpinia hintonii Complex (Leguminosae: Caesalpinioideae) in a Seasonally Dry Mexican Forest

Current phylogenetic studies for plant species across Europe and the tropics have been focused in areas that are more temperate or glacial.  This is perhaps the easiest since those regions are better recognized than the harsher desert areas.  Desert areas are harder to understand due to the complexity in a certain region that arises due to the local climate, soil type, and the features of the land around the vegetation that occurs.  What Sotuyo et al have set out to do is to discover dispersal patterns and evolutionary linkages between species of the Caesalpinia hintonii complex in the Rio Blasas Depression and Tehuacan-Cuicatlan Vally of Mexico.  Those regions are geographically complex and had provided a lot of samples for study.  They took a total of 60 individuals for sampling from 13 different populations and sequenced for four plastid regions.  The accd-psaI spacer was used as well as the trnH-psbA intergenic spacer for PCR.  This revealed that there are two lineages that have arisen in the Rio Blasas Depression and Tehuacan-Cuicatlan Vally.  These two lineages, coined east and west, as well as other outgroups of these lineages were the product of many physical boundaries formed over the years and thus causing reproductive isolation of the refugia that had dispersed in certain areas.

Sotuyo, Solange, Delgado-Salinsa, Alfonso, Chase, Mark W., Lewis, Gwilym P., and Oyama, Ken. 2007. Cryptic Species in the Caesalpinia hintonii Complex (Leguminosae: Caesalpinioideae) in a Seasonally Dry Mexican Forest. Annals of Botany 100 (6): 1307-1314.