The extraordinary journey of Peperomia subgenus Tildenia (Piperaceae): insights into diversification and colonization patterns from its cradle in Peru to the Trans-Mexican Volcanic Belt

Abstract

Aim : Peperomia subgenus Tildenia consists of c. 60 species growing in seasonal habitats of Neotropical mountain areas from Mexico to Argentina. The subgenus can be split geographically, with almost equal diversity in the Northern Hemisphere (centred in Mexico and Guatemala) and in the Southern Hemisphere (centred in Peru and Bolivia). Only a few species are known from a limited number of localities between these two hotspots. As such, Tildenia is an ideal candidate with which to test time, direction and mode of migration of high mountain taxa against the background of the Great American Biotic Interchange. Location : The Andes with focus on the Central Andes, and the Mexican mountain chains, especially the Trans-Mexican Volcanic Belt. Methods : To elucidate the spatio-temporal origin, subsequent colonization and radiation of Tildenia, we combine Bayesian phylogenetics based on the chloroplast trnK-matK-psbA region, georeferenced distribution data, and fossil calibrated molecular dating approaches using both penalized likelihood and relaxed phylogenetics. Reconstruction of the ancestral distribution area was performed using dispersal-vicariance analysis and dispersal-extinction-cladogenesis. Results : Peperomia subgenus Tildenia is subdivided into six Andean clades and one Mexican and Central American clade originating from a north/central Peruvian ancestor. Molecular dating approaches converge on a stem age of c. 38 Ma for Tildenia and a mostly Miocene diversification and colonization. Main conclusions : We detect a strong correlation between diversification of Tildenia and orogenetic events in the respective distribution centres. In the Andes, distribution was influenced by the Altiplano-Eastern Cordillera System as well as the Amotape-Huancabamba Zone, where the latter serves as both migration barrier and migration bridge for different clades. In contrast to most studies of high-elevation taxa, we provide support for a south-north colonization towards Central America and Mexico, and provide additional, independent evidence for the latest view on the timing of the Great American Biotic Interchange. In Mexico, the Trans-Mexican Volcanic Belt has played a major role in more recent radiations together with climatic oscillation and the formation of refugia

Phylogenetic insights into Andean plant diversification

“…The Amotape-Huancabamba zone might represent a dispersal barrier for high-elevation lineages under current climatic conditions. Support for this idea has been found in the distribution of groups such as Lithospermum (Boraginaceae; Weigend et al, 2010), Macrocarpea (Gentianaceae; Struwe et al, 2009), Nasa (Loasaceae; Weigend, 2002), Peperomia (Piperaceae; Symmank et al, 2011). The Central Andes are situated between the Amotape-Huancabamba zone and the southern limit of the dry Puna around 25-29 • S, where the precipitation regime changes from summer-rainfall to winter-rainfall (Luebert and Pliscoff, 2006), which is paralleled by floristic turnover (Villagrán et al, 1983;Martínez-Carretero, 1995;Arroyo et al, 1997Arroyo et al, , 1998.…”

“…In Peperomia subg. Tildenia, Central American taxa originated from central Andean ancestors around 15 Ma (Symmank et al, 2011). These authors suggest a northern Andean track and subsequent extinction of the group in the Northern Andes, since the current northern limit of Peperomia subg.…”

“…Tildenia (Piperaceae), there are several central-Andean clades, all of which started their diversification after ca. 13 Ma, coincident with the onset of central Andean uplift (Symmank et al, 2011). Poa sect.…”

Biogeographic Barriers in the Andes: Is the Amotape—Huancabamba Zone a Dispersal Barrier for Dry Forest Plants?

“…The high number of species shared between the Bolivian Andes and the central Andean region was already commented on by Linares-Palomino et al (2011), who found a strong floristic similarity between these two regions. Vicariance and long-distance dispersal events in combination have been discussed as the basis of widespread distributions of Neotropical SDTF species (Prado & Gibbs, 1993;Pennington et al, 2006;Symmank et al, 2011;Pennington & Lavin, 2016).…”

Worldwide long‐distance dispersal favored by epizoochorous traits in the biogeographic history of Omphalodeae (Boraginaceae)

“…The existence of island arcs between the two continents at around 15 mya (Krzywinski et al, ) could have facilitated this LDD. Indeed, biotic exchange for numerous plant lineages has been invoked before complete closure (e.g., Chloranthaceae, Antonelli & Sanmartin, ; Valerianaceae, Bell & Donoghue, ; Ephedra , Ickert‐Bond et al, ; Begonia , Moonlight et al, ; Piperaceae, Symmank et al, ). Colonization of Chile via LDD from the northern Andes led to the diversification of Chilean Selkirkia s.l.…”