Multivariate morphometric analysis and species delimitation in the endemic New Caledonian genus [i]Storthocalyx[/i] (Sapindaceae)
Résumé
Storthocalyx is one of four genera of Sapindaceae endemic to New Caledonia. The most recent taxonomic revision is > 60 years old and is based on material that represents < 10% of the collections available today. Four species are currently recognized: Storthocalyx chryseus, Storthocalyx leioneurus, Storthocalyx pancheri, and Storthocalyx sordidus, although a significant number of specimens cannot be assigned to any of them. One hundred and ninety-eight herbarium specimens were examined for an ascendant hierarchical classification and a principal coordinates analysis based on 19 morphological characters regarded as diagnostic at the species level (including those used in the original revision). The analyses revealed five morphologically well delimited groups that potentially correspond to species-level units. The resulting entities were then compared with nomenclatural types, which showed that four of them corresponded to the four currently recognized species and suggested that the fifth represents a well delimited, undescribed species. The analysis also showed that seven type specimens represent mixed gatherings comprising elements referable to two distinct species. The findings of the present study provide a basis for undertaking a taxonomic revision of Storthocalyx, including the description of the new species