Molecular phylogeny of the Mammilloid clade (Cactaceae) resolves the monophyly of Mammillaria

Abstract

To resolve more than 150 years of taxonomic confusion regarding the genus Mammillaria, the molecular phylogeny of the Mammilloid clade, including the genera Cochemiea, Coryphantha, Cumarinia, Escobaria, Mammillaria, Neolloydia, and Ortegocactus, is reconstructed. We included broad sampling of genera as well as a regionally nearly complete taxon sampling of Mammillaria and Cochemiea from the Baja California region. Employing the large single-copy region of the plastid genome as sequence data, we conducted maximum likelihood, maximum parsimony and Bayesian inference to reconstruct a molecular phylogeny of the clade. The molecular phylogenetic topology was further supported by reconstructing the ancestral states of 10 characters, from which three traditionally taxonomically important characters for the sampled taxa were selected. Results from our analyses clarify the evolutionary relationships of these closely related taxa, providing high resolution with strongly supported clades and subclades. The genus Mammillaria as currently circumscribed is non-monophyletic, and thus, we propose a recircumscription of the Mammilloid clade yielding three monophyletic genera, Mammillaria s.str., Cochemiea s.l. and Coryphantha. We herein make appropriate combinations to accommodate our circumscription of these genera.

Evaluating the monophyly of Mammillaria series Supertextae (Cactaceae)

“…However, it has been proposed that Mammillaria is a polyphyletic group. Breslin et al (2021), using plastid genomes, confirmed previous studies showing Mammillaria is nonmonophyletic, as currently circumscribed, so they proposed that the Mammilloid clade be circumscribed in three monophyletic genera, Mammillaria s.s., Coryphantha and Cochemiea s.l., as previously suggested by Vázquez- Sánchez et al (2013). Furthermore, the taxonomy of Mammillaria has historically been difficult due to large morphological variability, phenotypic plasticity, sympatric distribution of species, and suspected hybridization events.…”

Phylogenetic relationships in Coryphantha and implications on Pelecyphora and Escobaria (Cacteae, Cactoideae, Cactaceae)

“…In the molecular analysis, Mammillaria sphacelata and M. benecki were recovered, with low support, as the sister group to Coryphantha s.s. In contrast, Breslin et al (2021) found M. sphacelata to be the sister to Escobaria + Coryphantha . The addition of eight morphological characters in the combined analysis recovered M. sphacelata and M. beneckei within the clade Mammillaria , and supported Coryphantha s.s. and Escobaria as sister lineages.…”

“…Finally, Breslin et al (2021) proposed Escobaria and Coryphantha to be a single genus, as traditionally treated by North American botanists ( Benson 1982 ; Zimmerman and Parfitt 2004 ). However, sampling in Mexican Coryphantha was not representative.…”

“…Overall, these phylogenetic studies suggest that Coryphantha is not monophyletic ( Bárcenas et al 2011 ; Vázquez-Sánchez et al 2013 ). Recently, Breslin et al (2021) proposed the recircumscription of the mammilloid clade by recognizing three genera, Mammillaria , Cochemiea (K.Brandegee), and Coryphantha (including Escobaria ). However, sampling in the Coryphantha clade was poor.…”

Growth Patterns in Seedling Roots of the Pincushion Cactus Mammillaria Reveal Trends of Intra- and Inter-Specific Variation

“…is nonmonophyletic (Butterworth and Wallace, 2004), and recently it was also proposed that the Mammiloid clade circumscribes three monophyletic genera: Mammillaria s.s., Coryphantha and Cochemiea s.l. (Breslin et al, 2021). The Mammilloid clade is estimated to have diverged for the last 8.62 million years (Hernández-Hernández et al, 2014).…”