Molecular systematics of the trans‐Pacific alpine genusOreomyrrhis(Apiaceae): phylogenetic affinities and biogeographic implications

Abstract

The alpine ecosystem is the only terrestrial biogeographic unit that is distributed globally. Studying phylogenetics of the plant species in this widespread ecosystem can provide insights into the historical biogeographic processes that have shaped the global biodiversity. The trans-Pacific disjunct alpine genus Oreomyrrhis (Apiaceae) was investigated using nrDNA ITS sequences to test the taxonomic and biogeographic hypotheses. Phylogenetic analyses using maximum parsimony, maximum likelihood, and Bayesian inference revealed that species of Oreomyrrhis form a weakly supported monophyletic clade that is nested within Chaerophyllum sect. Chaerophyllum (subtribe Scandicinae, tribe Scandiceae). The optimal solutions of dispersal-vicariance analysis indicate that the ancestor of Chaerophyllum sect. Chaerophyllum (including Oreomyrrhis) was distributed in Eurasia and subsequently dispersed to North America and southern Pacific Rim. Based on dating using ITS sequence variation, these dispersal events were most likely recent, probably during late Tertiary to Quaternary. The structure of the ITS haplotype network suggests that a rapid range expansion via long-distance dispersal had been crucial in generating the trans-Pacific disjunction of Oreomyrrhis. Furthermore, evolution toward smaller mericarp size and a transition from outcrossing to selfing during Oreomyrrhis's evolution might have increased the chances for long-distance dispersal, facilitating its range expansion and occupation on alpine environments.

Tropical and Temperate: Evolutionary History of Páramo Flora

“…5 Phylogeny of Anthospermeae suggests repeated dispersals from Australasia to South America and the nested position of Nertera indicates a south temperate affinity of the genus (modified from Anderson et al, 2001, Fig. 3) which prevents biogeographic reconstruction and leaves the origin of O. andicola in páramo unclear (Chung et al, 2005).…”

“…25 herbaceous species of which O. andicola is found in páramo, provides another example of a disjunct trans-Pacific distribution (Mathias & Constance, 1955;Luteyn, 1999). Since mericarps of Oreomyrrhis do not posses any apparent adaptations to dispersal (Mathias & Constance, 1955;Chung et al, 2005), long-distance trans-oceanic dispersal was doubted in favor of ancient land migration and vicariance events (Mathias & Constance, 1955;van Steenis, 1962). Nevertheless, phylogeny of Oreomyrrhis, based on nuclear DNA markers, suggests a late Tertiary to Quaternary origin and diversification of the genus, rejecting the vicariance scenarios (Chung et al, 2005) in favour of a long-distance dispersal between South America and Australasia/New Zealand.…”

The infrageneric taxonomy ofChaerophyllum(Apiaceae) revisited: new evidence from nuclear ribosomal DNA ITS sequences and fruit anatomy

“…with c . 26 species is nested in Chaerophyllum (Chung et al ., ). Subsequently, the former was subsumed into the latter (Chung, ).…”

A New Species in the Lomatium foeniculaceum (Apiaceae) Clade Revealed Through Combined Morphometric and Phylogenetic Analyses

“…The use of molecular data has stimulated research into new methodologies for analyzing the data (Baum and Shaw 1995;Dettman et al 2003;Hebert et al 2003;Carstens and Knowles 2007;Knowles and Carstens 2005; O'Meara 2010) and has uncovered species boundaries (Dettman et al 2003;Hebert et al 2004;Olson et al 2004;Carstens and Knowles 2007;Costea et al 2009;Patsch et al 2010;Kennedy and Watson 2010). Apiaceae has been the focus of several molecular phylogenetic analyses (Plunkett et al 1996a;Plunkett et al 1996b;Soltis and Novak 1997;Downie et al 1998;Downie and Katz-Downie 1999;Hardig and Soltis 1999;Downie et al 2000;Downie et al 2002;Chung et al 2005;Calviño et al 2006). Within Apiaceae, Lotnatium has been the most extensively studied (Soltis and Novak 1997;Hardig and Soltis 1999;Downie et al 2002), but much of the research has been at the intergenic or interspecific level.…”