Phylogeny and circumscription of antillean Anemotrochus, gen. nov., and Tylodontia (Apocynaceae: Asclepiadoideae: Gonolobinae)

Abstract

Combined molecular and morphological analyses demonstrate that a number of small-flowered Caribbean Asclepiadoideae of hitherto uncertain affiliation form two independent lineages in Asclepiadeae-Gonolobinae, and not, as previously assumed, in the Metastelmatinae. One lineage is described as the new genus Anemotrochus, which includes the widespread Caribbean A. eggersii, a species originally described under Metastelma; A. yamanigueyensis, a new species discovered by the authors in E Cuba; and A. viridivenius, a plant from Hispaniola formerly assigned to Matelea. The second lineage, Tylodontia, is a small genus restricted to Cuba. Besides its type species, T. cubensis, the genus comprises T. fuscula, a species formerly assigned to Metastelma; T. stipitata, a new species described here; and T. urceolata, a species formerly assigned to Astephanus. Anemotrochus and Tylodontia belong to the wider Matelea alliance, but they form endemic Antillean, mainly Cuban lineages independent from Matelea. All species, except for A. viridivenius, are fully described and illustrated, and distribution maps are provided. The names Metastelma eggersii and Astephanus schlechterianus (a synonym of T. fuscula) are lectotypified here.