Open AccessPhylogenetics of tribe Sabiceeae (Ixoroideae, Rubiaceae) revisited, with a new subgeneric classification for Sabicea
Author(s) -
Zemagho Lise,
LiedeSchumann Sigrid,
Sonké Bonaventure,
Janssens Steven,
Lachenaud Olivier,
Verstraete Brecht,
Dessein Steven
Publication year - 2016
Publication title -
botanical journal of the linnean society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.872
H-Index - 68
eISSN - 1095-8339
pISSN - 0024-4074
DOI - 10.1111/boj.12475
Subject(s) - subgenus , monophyly , biology , tribe , clade , genus , maximum parsimony , phylogenetic tree , taxon , zoology , evolutionary biology , botany , genetics , sociology , gene , anthropology
Tribe Sabiceeae (Ixoroideae, Rubiaceae) has undergone recent taxonomical changes with the incorporation of the related genera Ecpoma , Pseudosabicea and Stipularia into the type genus Sabicea . We use phylogenetic analysis and morphological data to verify the relationships among members of the tribe, including the most comprehensive taxon sampling of the tribe to date with 74 of 145 species. Sequence data from the nuclear internal transcribed spacer (ITS) and three plastid markers ( petD , rps16 , trnT–F ) were used to infer relationships among the members of the tribe. Individual analyses using maximum likelihood, parsimony and Bayesian approaches reveal several supported clades: the former genus Stipularia is resolved as a monophyletic unit, but Ecpoma is monophyletic only if Sabicea urbaniana and Sabicea xanthotricha are included (corresponding to Sabicea subgenus Stipulariopsis sensu Wernham). Pseudosabicea is biphyletic, with one clade corresponding to section Anisophyllae of Hallé (1964) and the other one to the other sections ( Floribundae and Sphaericae ) of the genus. Eleven morphological characteristics were recorded for all species studied and seven have been mapped onto the phylogenetic tree to study their evolution in the group and assess their value for the classification of Sabicea s.l . Finally, our study shows that a combination of diagnostic characteristics should be used to differentiate each group and we propose to recognise four subgenera in Sabicea .