Islands within islands: a molecular phylogenetic study of the Leucocroton alliance (Euphorbiaceae) across the Caribbean Islands and within the serpentinite archipelago of Cuba

Abstract

Aim Our aim was to investigate the historical biogeography of the three genera of the Leucocroton alliance (i.e. Garciadelia Jestrow & Jiménez Rodr., Lasiocroton Griseb., and Leucocroton Griseb., Euphorbiaceae). Location The alliance is restricted to the Bahamas, Cuba, Hispaniola and Jamaica. Methods Members of the Leucocroton alliance, along with representatives from tribe Adelieae (Adelia L. and Philyra Klotzsch.), were included in a molecular phylogenetic analysis based upon nucleotide sequences of the internal transcribed spacer region of the nuclear ribosomal DNA and the non‐coding chloroplast regions psbM–trnD and ycf6–pcbM. The program s‐diva was used to calculate ancestral areas based on the phylogenetic trees and present species distributions. Results Phylogenetic analyses support the monophyly of the three genera. The ancestral area of the Leucocroton alliance is eastern Cuba and Hispaniola. Ancestral forms of Leucocroton arose on eastern Cuba and underwent two migrations across the island. The ancestor of Lasiocroton also originated on eastern Cuba followed by later dispersal to and speciation events on the other islands. Our study also suggests that ancestral forms of the Leucocroton alliance probably occurred on limestone soils. Main conclusions Our study concurs with previous hypotheses suggesting that the flora of serpentinite regions of the Caribbean derives from other types of soils. The serpentine endemics of the Leucocroton alliance have a single origin and represent one of the most extraordinary examples of speciation in this unique environment of the New World. The high colonization success achieved by the members of Leucocroton on serpentine soils was not attained by the other genera of the alliance, which occur on limestone areas.

Phylogenetics and Biogeography of the Genus <I>Metastelma</I> (Apocynaceae-Asclepiadoideae-Asclepiadeae: Metastelmatinae)

“…2, 3). Similarly to the results from Jestrow et al (2012) for Leucocroton (Euphorbiaceae), our data do not support a strict eastern-western split for the Cuban taxa. The three accessions of the M. northropiae complex analyzed here are retrieved as sister to the Cuban taxa (Fig.…”

Successive arrivals since the Miocene shaped the diversity of the Caribbean Acalyphoideae (Euphorbiaceae)

“…(b) Acidoton‐Platygyna clade: A. microphyllus (), A. variifolius (), P. dentata (), P. hexandra (), P. leonis (), P. obovata (), P. parvifolia (); hatching indicates the reported distribution of Platygyna sensu Borhidi, . (c) Leucocroton – Lasiocroton – Garciadelia clade: G. abbottii (), G. castilloae (), G. mejiae (), Lasiocroton bahamensis (), L. fawcettii (), L. gutierrezii (), L. harrisii (), L. microphyllus (), Leucocroton virens and L. wrightii (), L. obovatus , L. pachyphyllus and L. pallidus (); grey shadows show the ultramafic massifs of Cuba where Leucocroton is distributed (taken from Jestrow et al ., ). Photographs of some species of the Caribbean clades: (d) Platygyna parvifolia , (e) Bernardia dichotoma , (f) Lasiocroton bahamensis and (g) Leucocroton revolutus .…”

Historical Biogeography of endemic seed plant genera in the Caribbean: Did GAARlandia play a role?

“…Our results of a Central American ancestor disagree with those reported in the literature in two cases. The first is the endemic clade Lasiocroton – Leucocroton (Euphorbiaceae), for which Jestrow, Gutiérrez, and Francisco‐Ortega () and Cervantes et al. () suggested an ancestor in eastern Cuba and the Antilles, respectively.…”