The importance of environmental conditions in maintaining lineage identity in Epithelantha (Cactaceae)

Abstract

• The use of environmental variables to explain the evolution of lineages has gained relevance in recent studies. Additionally, it has allowed the recognition of species by adding more characters to morphological and molecular information. This study focuses on identifying environmental and landscape variables that have acted as barriers that could have influenced the evolution of Epithelantha species and its close genera.

• Our results show that soil pH, isothermality, temperature seasonality, and annual precipitation have a significant phylogenetic signal for Epithelantha. Soil type and landforms are also relevant as ecological barriers that maintain the identity of Epithelantha species.

• The variables associated with the soil (pH) have influenced the evolution of Epithelantha and probably in other genera of Cactaceae. Additionally, Epithelantha is frequent in the piedmont and haplic kastanozems. Bioclimatic variables reinforce the recognition of E. micromeris, and E. cryptica as independent species. Therefore, ecology can be considered as a factor to explain the high level of endemism in Cactaceae.

Abstract

Speciation and species delimitation in megadiverse groups has always been a challenge. Here, we analyzed the impact of environmental conditions in maintaining lineage identity in an endemic cactus.