A 638‐gene phylogeny supports the recognition of twice as many species in the Malagasy endemic genusCapurodendron(Sapotaceae)

Abstract

AbstractThe Malagasy genusCapurodendroncurrently accommodates 26 described species and is the largest genus of the family Sapotaceae in Madagascar. These species are frequently logged because of their valued hardwood, which potentially puts them at risk of extinction. Species‐level identifications are often problematic, and this hinders both an accurate assessment of their conservation status and the development of effective protection measures. We sorted all the material (ca. 860 collections) available in the herbaria with significant collections for Madagascar into 47 putative species based on morphology. On 41 of these, for which we were able to retrieve suitable DNA, we conducted a phylogenetic reconstruction based on molecular sequences of 638 loci from 108Capurodendronspecimens, performing a target capture approach combined with next‐generation sequencing. Maximum likelihood (RAxML), pseudocoalescence (ASTRAL), and coalescence (STACEY) analyses showed thatCapurodendroncomprises two deeply divergent lineages. One, which includes a single species, is here newly described asC. subg.Reflexisepalabased on its distinctive morphology. The second lineage contains all remaining species, which seem to have resulted from a rapid radiation event. The phylogenetic tree provides good support for most of the species hypothesized based on morphology, with the exception of two species‐groups that we have named the Arid Complex and the Eastern Complex. As many as 20 species‐level lineages genetically distinct from any of the currently recognized species were identified, 17 of which were morphologically well‐characterized, representing strong candidates for new species. This would suggest thatCapurodendronis the most species‐rich endemic genus of plants in Madagascar. While 14 of these 20 clades are still under study, we here describe six species new to science:Capurodendron andrafiamenae(provisionally assessed as CR),C. aubrevillei(VU),C. birkinshawii(CR),C. naciriae(EN),C. randrianaivoi(CR), andC. sakarivorum(EN).Capurodendron oblongifoliumcomb. nov. (EN), previously regarded as a variety ofC. perrieri, represents a distinct lineage that is here recognized at the species level. The newly described species are illustrated by line drawings and photographs from the field, and a preliminary threat assessment is provided. We discuss the evolutionary history ofCapurodendronand also explore the question of node age estimates and their methodological limitations.