Phylogenetic relationships and phylogeography of relevant lineages within the complex Campanulaceae family in Macaronesia

Abstract

Macaronesia has long been recognized as a natural model for studying evolutionary processes in plant diversification. Several studies have attempted to focus on single lineages, and few have covered the diversification of a family across all the archipelagos. We used a comprehensive sample to clarify the phylogenetic relationships and the biogeographic history of the Macaronesian Campanulaceae. Hypotheses related to the colonization of these archipelagos will be used to examine the diversification patterns of different lineages. We sequenced the ITS region and six cpDNA markers (atpB, matK, petD, rbcL, trnL‐F, and psbA‐trnH) from 10 Campanulaceae species, including seven endemic species in Macaronesia. The phylogeny of these taxa was reconstructed using maximum parsimony, maximum likelihood, and Bayesian inference. To study the relationships within each lineage, haplotype networks were calculated using NeighborNet and TCS algorithms. Moreover, data were combined with fossil information to construct time‐calibrated trees for the Macaronesian Campanulaceae species. The phylogenetic analyses are largely congruent with current taxon circumscriptions, and all the endemic genera formed monophyletic clades, namely Azorina in Azores; Musschia in Madeira; and Campanula in Cape Verde. The Azorina clade and the Cape Verde endemic Campanula may share a common ancestor in North Africa, and the divergence was dated ca. 12.3 million years ago (Mya). The divergence of the Musschia clade began in the Pliocene ca. 3.4 Mya. Moreover, several examples of intraspecific variation were revealed among the native species with a clear geographic structured patterns, suggesting that cryptic diversity might exist within the native Macaronesian Campanulaceae when compared to the close mainland taxa (e.g., Campanula erinus, Trachelium caeruleum), but additional studies are needed to support the molecular data. This study highlights the power of combining data (e.g., phylogeny and divergence times, with species distribution data) for testing diversification hypotheses within the unique Macaronesian flora, providing useful information for future conservation efforts.

The Role of Climate and Topography in Shaping the Diversity of Plant Communities in Cabo Verde Islands

“…Barres et al [72] document differentiation between the populations of the northern and southern Cabo Verde Islands, which is also reported for other lineages, such as Globularia amygdalifolia and Umbilicus schmidtii [54], Echium [73], and Campanula jacobaea [74]. Menezes et al [75] estimate 9.56 Ma as the age of divergence between Cabo Verde's endemic Campanula species (C. jacobaea and C. bravensis) and their African sister species, i.e., it is related to the beginning of the aridification process of North and Northwest Africa. However, the divergence between C. jacobaea and C. bravensis is recent (Pleistocene, 0.01 Ma) [75].…”

“…Menezes et al [75] estimate 9.56 Ma as the age of divergence between Cabo Verde's endemic Campanula species (C. jacobaea and C. bravensis) and their African sister species, i.e., it is related to the beginning of the aridification process of North and Northwest Africa. However, the divergence between C. jacobaea and C. bravensis is recent (Pleistocene, 0.01 Ma) [75].…”

Shortcomings of Phylogenetic Studies on Recent Radiated Insular Groups: A Meta-Analysis Using Cabo Verde Biodiversity

“…Maximum Parsimony (MP) [13,14] has proven to be useful when dealing with recently diverged species with short branches and was commonly used as a standalone solution in earlier Macaronesian studies to resolve the phylogenetic relationships of some plant lineages (e.g., Convolvulus (Convolvulaceae) [15]; Gonosperminae (Asteraceae) [16]; Bencomia (Rosaceae) [17]; Pericallis (Asteraceae) [18]). More recent studies have followed the general trend, and usually couple MP approaches with other methods (i.e., ML and/or BI), providing better and more supported hypotheses, namely in several plant lineages: Lactuca (Asteraceae) [19]; Cistus (Cistaceae) [20]; Azorina, Campanula, Trachelium, Lobelia, Musschia, and Wahlenbergia (Campanulaceae) [21]; and endemic reptile genera: Gallotia (Lacertidae) [22]; Hemidactylus (Gekkonidae) [23].…”

“…To specifically perform ML and BI analysis with Macaronesian reptiles (Table 1) and plant lineages [19,20,21,31,32,33,34], two main software packages have also been often used: RAxML [52] and MrBayes [53]. Randomized Axelerated Maximum Likelihood (RAxML), and similar software packages such as PHYML [54] and GARLI [55], make use of ML estimations to perform phylogenetic inference; while MrBayes estimates phylogenies using a variant of the MCMC method called Metropolis-coupled MCMC.…”

Tracing insular woodiness in giant Daucus (s.l.) fruit fossils from the Early Pleistocene of Madeira Island (Portugal)

“…In Macaronesian archipelagos (Azores, Madeira, Canaries and Cabo Verde; Atlantic Ocean), insular woodiness is found among several plant families, including Apiaceae, Asteraceae, Boraginaceae, Campanulaceae, Euphorbiaceae, Geraniaceae and Scrophulariaceae (Jardim & Menezes de Sequeira, ; Lens & al., ). Phylogenetic and molecular dating studies of the Macaronesian flora are still infrequent, but their results indicate different timing of arrival and speciation of neoendemics within and between the archipelagos (e.g., Kim & al., ; Spalik & al., ; Menezes & al., ). However, due to the nature of phylogenetic data and analysis, the timing of the triggering of insular woodiness is currently impossible to track.…”