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Timing and tempo of early and successive adaptive radiations in Macaronesia.

Kim SC, McGowen MR, Lubinsky P, Barber JC, Mort ME, Santos-Guerra A - PLoS ONE (2008)

Bottom Line: Despite intensive investigation in the last 15 years, absolute age and rate of diversification are poorly known for the flora of Macaronesia.Subsequent inter-archipelago dispersal events into Madeira and the Cape Verdes took place very recently during the late Pliocene and Pleistocene after initial diversification on the Canary Islands.Our results demonstrate that opportunity for island colonization and successful radiation may have been constrained to discrete time periods of profound climatic and geological changes in northern African and the Mediterranean.

View Article: PubMed Central - PubMed

Affiliation: Department of Botany and Plant Sciences, University of California Riverside, Riverside, California, United States of America. sckim@ucr.edu

ABSTRACT
The flora of Macaronesia, which encompasses five Atlantic archipelagos (Azores, Canaries, Madeira, Cape Verde, and Salvage), is exceptionally rich and diverse. Spectacular radiation of numerous endemic plant groups has made the Macaronesian islands an outstanding area for studies of evolution and speciation. Despite intensive investigation in the last 15 years, absolute age and rate of diversification are poorly known for the flora of Macaronesia. Here we report molecular divergence estimates and rates of diversification for five representative, putative rapid radiations of monophyletic endemic plant lineages across the core eudicot clade of flowering plants. Three discrete windows of colonization during the Miocene and early Pliocene are suggested for these lineages, all of which are inferred to have had a single colonization event followed by rapid radiation. Subsequent inter-archipelago dispersal events into Madeira and the Cape Verdes took place very recently during the late Pliocene and Pleistocene after initial diversification on the Canary Islands. The tempo of adaptive radiations differs among the groups, but is relatively rapid compared to continental and other island radiations. Our results demonstrate that opportunity for island colonization and successful radiation may have been constrained to discrete time periods of profound climatic and geological changes in northern African and the Mediterranean.

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Phylogeny and age estimate of five flowering plant groups in the Macaronesian Islands.(A) the woody Sonchus alliance (Asterids, Euasterid II, Asterales) (species in the pictures, from top to bottom; Sonchus gandogeri*, S. acaulis*, and S. canariensis*) . (B) Echium (Asterids, Euasterid I, unplaced) (species in the pictures; Echium auberianum†, E. callithyrsum*, and E. wildpretii†). (C) the Aeonium alliance (Saxifragales) (species in the pictures; Aichryson punctatum ∏, Monanthes muralis∏, Greenovia aurea*, and Aeonium cuneatum∏). (D) Sideritis (Asterids, Euasterid I, Lamiales) (species in the pictures, top left, Sideritis gomerae¶; top right, S. macrostachys¶; bottom row, S. eriocephala¶). (E) Crambe (Rosids, Eurosid II, Brassicales) (species in the pictures; Crambe scaberrima§ and C. pritzelii§). Branch colors: gray, closest continental relatives; black, the Canary Islands; blue, Madeira; red, Cape Verde. Branch lengths are proportional to changes on the trees and outgroup taxa are not shown. (photo credits: *Seung-Chul Kim, †Jose Mesa, ¶Janet C. Barber, §Manuel Luis Gil González, and ∏Mark Mort).
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pone-0002139-g002: Phylogeny and age estimate of five flowering plant groups in the Macaronesian Islands.(A) the woody Sonchus alliance (Asterids, Euasterid II, Asterales) (species in the pictures, from top to bottom; Sonchus gandogeri*, S. acaulis*, and S. canariensis*) . (B) Echium (Asterids, Euasterid I, unplaced) (species in the pictures; Echium auberianum†, E. callithyrsum*, and E. wildpretii†). (C) the Aeonium alliance (Saxifragales) (species in the pictures; Aichryson punctatum ∏, Monanthes muralis∏, Greenovia aurea*, and Aeonium cuneatum∏). (D) Sideritis (Asterids, Euasterid I, Lamiales) (species in the pictures, top left, Sideritis gomerae¶; top right, S. macrostachys¶; bottom row, S. eriocephala¶). (E) Crambe (Rosids, Eurosid II, Brassicales) (species in the pictures; Crambe scaberrima§ and C. pritzelii§). Branch colors: gray, closest continental relatives; black, the Canary Islands; blue, Madeira; red, Cape Verde. Branch lengths are proportional to changes on the trees and outgroup taxa are not shown. (photo credits: *Seung-Chul Kim, †Jose Mesa, ¶Janet C. Barber, §Manuel Luis Gil González, and ∏Mark Mort).

Mentions: Three narrow windows of colonization were found for the five plant groups: Middle Miocene (early Serravllian), Late Miocene (late Tortonian), and Early Pliocene (early Zanclean). The Aeonium alliance, a well supported clade of three genera, showed the earliest colonization into the Canary Islands (15.2 Ma), followed by the woody Sonchus alliance (8.47 Ma), Crambe (8.15 Ma), Echium (3.73 Ma), and Sideritis (3.3 Ma) (Fig. 2 and Table 1). The most recent common ancestor (MRCA) of the Aeonium alliance colonized the Canaries when the two eastern-most, geologically older islands were formed during early to mid Tertiary. Within the Aeonium alliance, the MRCA ages of Aichryson, Monanthes, and Aeonium (including Greenovia) are estimated to be 8.67 Ma, 6.93 Ma, and 10.23 Ma, respectively. These divergence time estimates suggest that after the initial colonization, three major lineages slowly diverged and radiation of each lineage began during late Miocene. A second episode of synchronized colonization during the Late Miocene was inferred for Eurosid II and Euastrid II lineages: Crambe (Brassicaceae) and the Sonchus alliance (Asteraceae). Lastly, two of the most speciose and recently radiated lineages among the five investigated here are both members of the families in Euasterid I clade: Sideritis (Lamiaceae) and Echium (Boraginaceae); we infer that these taxa colonized the Canaries during the early Pliocene.


Timing and tempo of early and successive adaptive radiations in Macaronesia.

Kim SC, McGowen MR, Lubinsky P, Barber JC, Mort ME, Santos-Guerra A - PLoS ONE (2008)

Phylogeny and age estimate of five flowering plant groups in the Macaronesian Islands.(A) the woody Sonchus alliance (Asterids, Euasterid II, Asterales) (species in the pictures, from top to bottom; Sonchus gandogeri*, S. acaulis*, and S. canariensis*) . (B) Echium (Asterids, Euasterid I, unplaced) (species in the pictures; Echium auberianum†, E. callithyrsum*, and E. wildpretii†). (C) the Aeonium alliance (Saxifragales) (species in the pictures; Aichryson punctatum ∏, Monanthes muralis∏, Greenovia aurea*, and Aeonium cuneatum∏). (D) Sideritis (Asterids, Euasterid I, Lamiales) (species in the pictures, top left, Sideritis gomerae¶; top right, S. macrostachys¶; bottom row, S. eriocephala¶). (E) Crambe (Rosids, Eurosid II, Brassicales) (species in the pictures; Crambe scaberrima§ and C. pritzelii§). Branch colors: gray, closest continental relatives; black, the Canary Islands; blue, Madeira; red, Cape Verde. Branch lengths are proportional to changes on the trees and outgroup taxa are not shown. (photo credits: *Seung-Chul Kim, †Jose Mesa, ¶Janet C. Barber, §Manuel Luis Gil González, and ∏Mark Mort).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2367450&req=5

pone-0002139-g002: Phylogeny and age estimate of five flowering plant groups in the Macaronesian Islands.(A) the woody Sonchus alliance (Asterids, Euasterid II, Asterales) (species in the pictures, from top to bottom; Sonchus gandogeri*, S. acaulis*, and S. canariensis*) . (B) Echium (Asterids, Euasterid I, unplaced) (species in the pictures; Echium auberianum†, E. callithyrsum*, and E. wildpretii†). (C) the Aeonium alliance (Saxifragales) (species in the pictures; Aichryson punctatum ∏, Monanthes muralis∏, Greenovia aurea*, and Aeonium cuneatum∏). (D) Sideritis (Asterids, Euasterid I, Lamiales) (species in the pictures, top left, Sideritis gomerae¶; top right, S. macrostachys¶; bottom row, S. eriocephala¶). (E) Crambe (Rosids, Eurosid II, Brassicales) (species in the pictures; Crambe scaberrima§ and C. pritzelii§). Branch colors: gray, closest continental relatives; black, the Canary Islands; blue, Madeira; red, Cape Verde. Branch lengths are proportional to changes on the trees and outgroup taxa are not shown. (photo credits: *Seung-Chul Kim, †Jose Mesa, ¶Janet C. Barber, §Manuel Luis Gil González, and ∏Mark Mort).
Mentions: Three narrow windows of colonization were found for the five plant groups: Middle Miocene (early Serravllian), Late Miocene (late Tortonian), and Early Pliocene (early Zanclean). The Aeonium alliance, a well supported clade of three genera, showed the earliest colonization into the Canary Islands (15.2 Ma), followed by the woody Sonchus alliance (8.47 Ma), Crambe (8.15 Ma), Echium (3.73 Ma), and Sideritis (3.3 Ma) (Fig. 2 and Table 1). The most recent common ancestor (MRCA) of the Aeonium alliance colonized the Canaries when the two eastern-most, geologically older islands were formed during early to mid Tertiary. Within the Aeonium alliance, the MRCA ages of Aichryson, Monanthes, and Aeonium (including Greenovia) are estimated to be 8.67 Ma, 6.93 Ma, and 10.23 Ma, respectively. These divergence time estimates suggest that after the initial colonization, three major lineages slowly diverged and radiation of each lineage began during late Miocene. A second episode of synchronized colonization during the Late Miocene was inferred for Eurosid II and Euastrid II lineages: Crambe (Brassicaceae) and the Sonchus alliance (Asteraceae). Lastly, two of the most speciose and recently radiated lineages among the five investigated here are both members of the families in Euasterid I clade: Sideritis (Lamiaceae) and Echium (Boraginaceae); we infer that these taxa colonized the Canaries during the early Pliocene.

Bottom Line: Despite intensive investigation in the last 15 years, absolute age and rate of diversification are poorly known for the flora of Macaronesia.Subsequent inter-archipelago dispersal events into Madeira and the Cape Verdes took place very recently during the late Pliocene and Pleistocene after initial diversification on the Canary Islands.Our results demonstrate that opportunity for island colonization and successful radiation may have been constrained to discrete time periods of profound climatic and geological changes in northern African and the Mediterranean.

View Article: PubMed Central - PubMed

Affiliation: Department of Botany and Plant Sciences, University of California Riverside, Riverside, California, United States of America. sckim@ucr.edu

ABSTRACT
The flora of Macaronesia, which encompasses five Atlantic archipelagos (Azores, Canaries, Madeira, Cape Verde, and Salvage), is exceptionally rich and diverse. Spectacular radiation of numerous endemic plant groups has made the Macaronesian islands an outstanding area for studies of evolution and speciation. Despite intensive investigation in the last 15 years, absolute age and rate of diversification are poorly known for the flora of Macaronesia. Here we report molecular divergence estimates and rates of diversification for five representative, putative rapid radiations of monophyletic endemic plant lineages across the core eudicot clade of flowering plants. Three discrete windows of colonization during the Miocene and early Pliocene are suggested for these lineages, all of which are inferred to have had a single colonization event followed by rapid radiation. Subsequent inter-archipelago dispersal events into Madeira and the Cape Verdes took place very recently during the late Pliocene and Pleistocene after initial diversification on the Canary Islands. The tempo of adaptive radiations differs among the groups, but is relatively rapid compared to continental and other island radiations. Our results demonstrate that opportunity for island colonization and successful radiation may have been constrained to discrete time periods of profound climatic and geological changes in northern African and the Mediterranean.

Show MeSH