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A widespread radiation in the Periplocoideae (Apocynaceae): The case of Cryptolepis
Author(s) -
Joubert Lize,
Klak Cornelia,
Venter Andor M.,
Venter Hendrik J.T.,
Bruyns Peter V.
Publication year - 2016
Publication title -
taxon
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 81
eISSN - 1996-8175
pISSN - 0040-0262
DOI - 10.12705/653.4
Subject(s) - paraphyly , monophyly , ecology , genus , biological dispersal , biology , biogeography , zoology , clade , geography , phylogenetic tree , demography , population , biochemistry , sociology , gene
Cryptolepis is the second‐largest genus in the Periplocoideae with 30 species. It is the most widely distributed genus in the subfamily and occupies a wide range of habitats, from moist forests to stony semi‐deserts. Analyses of DNA‐data revealed that Cryptolepis is paraphyletic and, for monophyly to prevail, Parquetina should be included in Cryptolepis . Most of the species fall into two major clades: one confined to NE Africa and neighbouring areas; the other absent from NE Africa but widely distributed from West to South Africa. Most species of Cryptolepis from the more arid areas are shrubby, often with reduced leaves and often with much reduced, few‐flowered inflorescences. We establish that Cryptolepis arose about 21 million years ago and began its major radiation around 16 million years ago. Despite this age and its wide distribution, it has not diversified significantly, perhaps limited in the more arid regions by the absence of succulence. It is also possible that the relatively uniform floral structure also limited its response to the diversity of pollinators. Although most species of Cryptolepis are African, there are three species in SE Asia. We show that these three SE Asian species are nested among African taxa and are likely to have reached SE Asia by long‐distance dispersal.