Biogeographical patterns and speciation of the genus Pinguicula (Lentibulariaceae) inferred by phylogenetic analyses

Abstract

Earlier phylogenetic studies in the genus Pinguicua (Lentibulariaceae) suggested that the species within a geographical region was rather monophyletic, although the sampling was limited or was restricted to specific regions. Those results conflicted with the floral morphology-based classification, which has been widely accepted to date. In the current study, one nuclear ribosomal DNA (internal transcribed spacer; ITS) and two regions of chloroplast DNA (matK and rpl32-trnL), from up to ca. 80% of the taxa in the genus Pinguicula, covering all three subgenera, were sequenced to demonstrate the inconsistency and explore a possible evolutionary history of the genus. Some incongruence was observed between nuclear and chloroplast topologies and the results from each of the three DNA analyses conflicted with the morphology-based subgeneric divisions. Both the ITS tree and network, however, corresponded with the biogeographical patterns of the genus supported by life-forms (winter rosette or hibernaculum formation) and basic chromosome numbers (haploidy). The dormant strategy evolved in a specific geographical region is a phylogenetic constraint and a synapomorphic characteristic within a lineage. Therefore, the results denied the idea that the Mexican group, morphologically divided into the three subgenera, independently acquired winter rosette formations. Topological incongruence among the trees or reticulations, indicated by parallel edges in phylogenetic networks, implied that some taxa originated by introgressive hybridisation. Although there are exceptions, species within the same geographical region arose from a common ancestor. Therefore, the classification by the floral characteristics is rather unreliable. The results obtained from this study suggest that evolution within the genus Pinguicula has involved; 1) ancient expansions to geographical regions with gene flow and subsequent vicariance with genetic drift, 2) acquirement of a common dormant strategy within a specific lineage to adapt a local climate (i.e., synapomorphic characteristic), 3) recent speciation in a short time span linked to introgressive hybridisation or multiplying the ploidy level (i.e., divergence), and 4) parallel evolution in floral traits among lineages found in different geographical regions (i.e., convergence). As such, the floral morphology masks and obscures the phylogenetic relationships among species in the genus.

Contributions to Ecuadorian butterworts (Lentibulariaceae, Pinguicula): two new species and a re-evaluation of Pinguicula calyptrata

“…from Colombia and Venezuela. This strange species is, contrary to traditional placements (Ernst 1961, Casper 1966, not closely related to the other Southern American taxa, but represents an isolated lineage with affinities to Mexican and European clades, as a recent molecular phylogenetic analysis has shown (Shimai et al 2021). Moreover, the leaves of P. jimburensis are only slightly elongated and otherwise flat with a distinct abaxial and adaxial leaf lamina and not involute as the almost filiform leaves of P. elongata, with the abaxial leaf surface sometimes completely hidden.…”

“…Species delimitation and the infrageneric classification of the genus in his works largely founded on morphological character complexes of the corolla, traditionally thought to be evolutionary stable. Instead, they were often subject to rapid diversifications and thereby prone to misinterpretations as recent molecular studies repeatedly revealed ( Lustofin et al 2020 ; Shimai et al 2021 , see Fleischmann 2021 for a detailed discussion). In the course of studying the Andean taxa, the late Siegfried Jost Casper (1929–2021) also based his allocation of new collections/observations on the gross flower morphology and (for the time being) tended to classify any observation from the Northern Andes with more or less spreading rosettes and bluish flowers with a yellow palate as P. calyptrata (pers.…”

A new endemic species and species richness distribution of the genus <i>Pinguicula</i> (Lentibulariaceae) in the Trans-Mexican Volcanic Belt, Mexico

“…The orientation of the mountain ranges favors the dispersal of northern elements to the south and vice versa (Zunino & Halffter 1988). Shimai et al (2021) explain the evolution within Pinguicula by ancient geographical expansions and gene flow, and subsequent vicariance with genetic drift. Whereas, Domínguez et al (2024) highlight the effects of climatic changes over time in the mountain chains of the MTZ, favoring speciation and persistence, which is reflected in the high species richness and endemism of Pinguicula (López-Pérez et al 2024).…”

“…Pinguicula grows in Eurasia, the Americas, and the Caribbean islands (Shimai et al 2021). All three subgenera are represented in Mexico, where 53 species have been recorded, 45 of which are endemics (López-Pérez et al 2024).…”

Taxonomic characteristics of carnivorous plants in the collection of the Botanical Garden of Vyatka State University

“…Виды и природные гибриды Nepenthaceae определяли согласно монографии M. R. Cheek, M. H. P. Jebb (2001), Sarraceniaceae -по Sarraceniaceae of South America и Sarraceniaceae of North America (McPherson, Schnell, 2011). Lentibulariaceae идентифицировали по H. Shimai (2017). По итогам инвентаризации 2022 г. насекомоядные растения в коллекции сада представлены 12 видами, одним подвидом, двумя природными гибридами, пятью культивируемыми гибридами и четырьмя сортами (табл., рис.).…”