Biogeographic Events Are Not Correlated with Diaspore Dispersal Modes in Boraginaceae

Abstract

Long-distance dispersal seems to be the main biogeographic event responsible for intriguing distribution patterns in plant groups in which sister taxa are separated by thousands of kilometers of distance across oceans and continents. The biotic and abiotic mechanisms behind such dispersal events are poorly understood and many attempts have been made to explain how plants can manage to disperse and survive these long journeys. The biogeographic history of Boraginaceae, a subcosmopolitan plant family with many disjunct clades, is here addressed and analyzed in the context of the different dispersal modes exhibited by the species. The lack of a clear pattern between the main dispersal events in Boraginaceae and the phylogenetic distribution of the dispersal modes indicates that no single dispersal mechanism can be associated with the events of dispersal in the family. Moreover, adaptations to different dispersal agents and unassisted dispersal modes in some clades might have promoted the diversification of Boraginaceae in various habitats across several continents. Our study reveals that long-distance dispersal is a very complex process that needs to be analyzed in the context of climatic and environmental changes and the response of plants and their dispersal vectors to these variable conditions.

Being in the right place at the right time? Parallel diversification bursts favored by the persistence of ancient epizoochorous traits and hidden factors in Cynoglossoideae

“…Moreover, the framework of molecular data in Boraginaceae is primarily plastid based, and plastid loci are used to maximize species representation. Therefore, two DNA plastid regions were chosen on the basis of previous studies of Boraginaceae (Weigend et al., ; Chacón et al., ): the trnL‐trnF intergenic spacer (including trnL intron) and the rps16 intron. Primers for the trnL‐trnF region were used as in Otero et al.…”

“…These seven areas were based on Chacón et al. () and Luebert et al. (), with special emphasis on the main areas of endemicity observed across lineages (e.g., existence of endemic genera in SE Asia: Antiotrema , Nihon , Sinojohnstonia , Thyrocarpus , and Trigonotis ; Zhu et al., ; Kadota, ).…”

“…This family is characterized by schizocarpic fruits that split into four one‐seeded units (although some exceptional species have one or two units; “nutlets,” Weigend et al., ). The most recent phylogenetic studies identify three subfamilies that differ not only in number of species but also in their distribution ranges: Boraginoideae (~610 spp., primarily in the western Palearctic and the Americas), Echiochiloideae (~30 spp., in North America, Africa, and southwestern Europe), and Cynoglossoideae (~1100 spp., cosmopolitan, widespread on all continents except the Antarctic) (Chacón et al., , ). These subfamilies are characterized by different fruit types (Gürke, ; Hilger, ).…”

Climate and host‐plant associations shaped the evolution of ceutorhynch weevils throughout the Cenozoic

“…However, single radiations in genera such as Ceutorhynchus and Mogulones s.l. are more likely the result of individual temporal and spatial adaptations to their plant hosts, where major radiations in Brassicaceae and Boraginaceae in the Holarctic are indicative of temperate-zone adaptations of these plants in the late Eocene and early Oligocene (Couvreur et al 2009;Chacón et al 2017). Consequently, ceutorhynch weevils appear to have responded to the abiotic environmental changes in the Northern hemisphere in the Cenozoic via biotic interactions with their specific hosts, which were in turn shaped by their own adaptation to these environmental changes.…”

A snapshot of progenitor-derivative speciation in action inIberodes(Boraginaceae)

“…The Mediterranean subendemic genus Iberodes M.Serrano, R.Carbajal & S.Ortiz (Boraginaceae, Cynoglossoideae; Serrano et al , 2016) provides an excellent system for studying recent speciation, morphological and ecological differentiation because it is clearly demonstrated to be a recently-derived genus (Chacón et al 2017, Otero et al 2019a). Iberodes comprises five species and one subspecies that differ in geographic ranges (including allopatric and parapatric species) and habitat (ranging from forest understories to scrublands and coastal dunes).…”