Species delimitation in Neolloydia Britton & Rose (Cacteae, Cactaceae)

This is the authors' abstract. We don't add key points for this paper.

Background: Neolloydia is a genus widely distributed in Mexico with notable morphological variation. In recent lists of Cactaceae, only Neolloydia conoidea has been recognized; however, previous reviews consider it to comprise a species complex. No studies have included statistical analyses of morphological variation, so species boundaries and recognition are uncertain. Questions: How many species should be recognized in the genus Neolloydia? Studied species: Genus Neolloydia Britton & Rose Study site and dates: Twenty-nine sites located in the Mexican states of Coahuila, Guanajuato, Hidalgo, Nuevo León, Querétaro, San Luis Potosí, Tamaulipas, and Zacatecas were explored between 2022 and 2024. Methods: Previous taxonomic proposals and a review of morphological traits allowed us to identify seven a priori groups. Ten quantitative and four qualitative traits were analyzed and tested using Random Forest classification analysis. Niche characterization was performed using GIS data (landform and soil type) from 189 records, followed by a chi-square goodness-of-fit test. Results: Random Forest classification analysis identified the seven a priori designated groups as independent. According to the chi-square goodness-of-fit test, the results are significant for landform and soil type. For two taxa, it was not possible to determine whether their distribution was non-random. Conclusions: A combination of morphological and niche characteristics supports the recognition of four species previously proposed by other authors; additionally, three new species are proposed.