Data Paper |
Corresponding author: Thomas Wagner ( thwagner@uni-koblenz.de ) Academic editor: Caroline Chaboo
© 2017 Thomas Wagner.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Wagner T (2017) Quo vadis biodiversity? Species richness following twenty years of taxonomic revisions on Afrotropical Galerucinae s. str. (Coleoptera, Chrysomelidae). In: Chaboo CS, Schmitt M (Eds) Research on Chrysomelidae 7. ZooKeys 720: 131-137. https://doi.org/10.3897/zookeys.720.14011
|
Galerucinae is one of the most species-rich leaf beetle group with its greatest diversity occurring in tropical forests. There are 1680 nominal species of Afrotropical Galerucinae s. str. (without Alticini) described. Considering global diversity estimations, many unknown species can be presumed. Several taxa traditionally placed in “Monoleptites”, have been revised in the last twenty years. To date 259 species have been re-examined, revealing in 139 valid species and 120 mainly newly recognized synonyms. This large number of synonyms can mainly be ascribed to highly variable colour patterns, a typical character used for the identification of many chrysomelid species. Genitalic structures and molecular work can support a more precise allocation to species. Within around 72,000 specimens of galerucines s. str. from 48 museums and private collections, only 107 species were newly described. After revising approximately 15% of the Afrotropical galerucine fauna their species richness decreased from 259 to 246 species, a pattern that appears to be similar to that for other African galerucine groups. Since the estimation of the extent of global diversity based mainly on insect species richness in tropical forests, our current study which is based on hard data suggests a much lower diversity than previously predicted.
Africa, Afrotropical, region, biodiversity, Galerucinae s. str., Monoleptites, revision, taxonomy
Galerucinae s. str. (without Alticini) is one of most diverse group of leaf beetles in tropical forests, including 1680 nominal species from Africa (
During a period of twenty years, our working group has revised approximately 85 % of the “Monoleptites” sensu
At present, some 250 species of Afrotropical Galerucinaes. str. have been revised and these data are used here as a case study on their general species richness. Global insect diversity caught the attention of entomologists, and a broader audience, in the 1980s, when data of canopy fogging in tropical forests were extrapolated to 30 million species of insects (
Our revisions of Afrotropical galerucines are currently published in 40 papers with a taxonomic focus (Wagner and collaborators 1993–2017) based on around 72,000 specimens from 48 collections which includes all the major museum collections that house African insects.
Up to now, 259 species have been re-examined, resulting in 139 valid species and 120, mainly newly recognized synonyms (Fig.
The high polychromatism in many galerucine species is the cause of the majority of synonyms, since colour patterns were used by previous authors as very definite species specific characters. When species are widely distributed, the number of synonyms increase even more. Monolepta vincta Gerstaecker, 1871, has a pan-Afrotropical distribution and ten synonyms have been found for his species (
Other diverse Afrotropical Galerucinae s. str. appear to indicate a similar “over-description” rate. Diacantha Chevrolat, 1836 (syn. Hyperacantha Chapuis, 1879) is the second most diverse group of African galerucines in terms of some 120 described species. A few spot checks revealed there are a large number of synonyms in this genus too, and Diacantha might be another taxonomic “nightmare”, revealing a lower number of valid species subsequent to formal revision.
On the other hand, revisions of tropical phytophagous insects can result in a strong increased number of species. Examples are the weevil genera Euops Schönherr, 1839 from New Guinea with 24 valid species before revision, and 160 additional new species there after (
Many thanks to all my co-workers for the taxonomic work, all students at several stages of their academic careers for the good work they did in sorting material, picking up label data, compiling distribution data, dissecting genitalia and doing the molecular work before writing their theses, Alexander Riedel for information on the south-east Asian weevils, and reviewers Ron Beenen, Jan Bezdek, Caroline Chaboo, Beth Grobbelaar, and one anonymous reviewer for valuable comments on the manuscript.
151st contribution to the taxonomy, phylogeny, and biogeography of the Galerucinae.
2Contribution to the 9th International Symposium on the Chrysomelidae, Orlando, FL, USA, September 28, 2016