A taxonomic dataset of preserved specimen occurrences of Theobroma and Herrania (Malvaceae, Byttnerioideae) stored in 2020

Abstract

Species from the "cacao group" are traditionally allocated into two genera, Theobroma and Herrania (Malvaceae, Byttnerioideae), both groups of Neotropical species economically relevant, such as the cacao tree (Theobroma cacao), which forms the source of chocolate. This study aimed at compiling and describing a dataset of preserved specimen collections available in the Global Biodiversity Information Facility repository (GBIF) for Tropical Americas. Data were exhaustively revisited and analysed in terms of taxonomic identity, conditions of collection and georeferencing, all of which should enable downstream taxonomic, geographic and evolutionary analyses. Our dataset compiles 7975 records of preserved specimen collections found at herbaria. Records are from 18 species of Theobroma and 14 of Herrania, occurring in 60 countries or major territories, with two species endemic to a single country (H. kofanorum from Ecuador and H. laciniifolium from Colombia). Occurrence records are mostly restricted to the Amazon rainforest and species with more occurrence records are cupuí, T. subincanum (1535 records), followed by the cacao tree, T. cacao (1500 records), the latter having cultivated specimens in Africa, Asia and Oceania. In the case of the genus Herrania, H. nitida and H. purpurea are the species with the majority of occurrences (respectively, 431 and 273 records). Most of the botanical samples from these genera are found in American, Brazilian and Colombian collections, with a particular strength for American herbaria. We describe how occurrence records are spread spatially and temporally and highlight key field expeditions responsible for enhancing most of the knowledge of cacao and its wild relatives, especially in countries where they prevail, such as Colombia (with 29 species), Ecuador (23 species), Brazil (18 species) and Peru (15 species). Specifically, expeditions in these countries were led by American and European initiatives in conjunction with local funding in the mid-20th century. We emphasise how initiatives of such kind seems to have weakened in the 21st century and most of the collections of Theobroma and Herrania made afterwards are from various collectors that seek to resample specimens in already explored sites.