TY - JOUR
T1 - DNA Sequence Variation among Conspecific Accessions of the Legume Coursetia caribaea Reveals Geographically Localized Clades Here Ranked as Species
AU - Lavin, Matt
AU - Pennington, R. Toby
AU - Hughes, Colin E.
AU - Lewis, Gwilym P.
AU - Delgado-Salinas, Alfonso
AU - Stefano, Rodrigo Duno De
AU - Queiroz, Luciano P.De
AU - Cardoso, Domingos
AU - Wojciechowski, Martin
N1 - Funding Information:
Comments by two anonymous reviewers improved the presentation of this manuscript. This work was supported in part by the USDA National Institute of Food and Agriculture, Hatch project 182272 to ML.
Publisher Copyright:
© Copyright 2018 by the American Society of Plant Taxonomists.
PY - 2018/8
Y1 - 2018/8
N2 - Coursetia caribaea is geographically and morphologically the most variable species in the genus Coursetia and in the tribe Robinieae (Leguminosae, Papilionoideae). Because of potentially undetected species, we assessed the phylogenetic relationships among the eight taxonomic varieties of C. caribaea. Sampling included nuclear ribosomal internal transcribed spacer sequences from 489 Robinieae accessions representing all varieties of C. caribaea and 38 of the 40 species of Coursetia, in addition to chloroplast trnD-trnT sequences from 186 accessions. Separate and combined phylogenetic analyses resolved a clade of conspecific accessions of the Bolivian C. caribaea var. astragalina as sister to the central Andean Coursetia grandiflora clade. Also distantly related to Coursetia caribaea var. caribaea accessions were those of the coastal Oaxacan C. caribaea var. pacifica, which formed the sister clade to accessions of the central Andean C. caribaea var. ochroleuca. The estimated mean ages of the stem clades for these three lineages, 11, 7.7, and 7.7 Ma, respectively, contrasted to the estimated mean ages of the corresponding crown clades of 0, 0, and 1.5 Ma. The contrasting stem and crown ages suggest that these taxa, appropriately ranked as species, Coursetia astragalina, Coursetia diversifolia, and Coursetia ochroleuca, each have persisted over evolutionary time frames as distinct geographically localized populations in seasonally dry tropical forests and woodlands.
AB - Coursetia caribaea is geographically and morphologically the most variable species in the genus Coursetia and in the tribe Robinieae (Leguminosae, Papilionoideae). Because of potentially undetected species, we assessed the phylogenetic relationships among the eight taxonomic varieties of C. caribaea. Sampling included nuclear ribosomal internal transcribed spacer sequences from 489 Robinieae accessions representing all varieties of C. caribaea and 38 of the 40 species of Coursetia, in addition to chloroplast trnD-trnT sequences from 186 accessions. Separate and combined phylogenetic analyses resolved a clade of conspecific accessions of the Bolivian C. caribaea var. astragalina as sister to the central Andean Coursetia grandiflora clade. Also distantly related to Coursetia caribaea var. caribaea accessions were those of the coastal Oaxacan C. caribaea var. pacifica, which formed the sister clade to accessions of the central Andean C. caribaea var. ochroleuca. The estimated mean ages of the stem clades for these three lineages, 11, 7.7, and 7.7 Ma, respectively, contrasted to the estimated mean ages of the corresponding crown clades of 0, 0, and 1.5 Ma. The contrasting stem and crown ages suggest that these taxa, appropriately ranked as species, Coursetia astragalina, Coursetia diversifolia, and Coursetia ochroleuca, each have persisted over evolutionary time frames as distinct geographically localized populations in seasonally dry tropical forests and woodlands.
KW - Neotropics
KW - Papilionoideae
KW - phylogenetics
KW - seasonally dry forests
KW - taxonomy
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U2 - 10.1600/036364418X697382
DO - 10.1600/036364418X697382
M3 - Article
AN - SCOPUS:85052240422
SN - 0363-6445
VL - 43
SP - 664
EP - 675
JO - Systematic Botany
JF - Systematic Botany
IS - 3
ER -