Global patterns of taxonomic uncertainty and its impacts on biodiversity research

Over two million species have been named so far, but many will be invalidated due to redundant descriptions. Undetected invalid species (i.e., synonyms) can impair inferences we make in biodiversity research and hamper the implementation of effective conservation strategies. However, the processes leading to the accumulation of invalid names remain largely unknown. Using multi-model inferences, we investigated the patterns and potential drivers of species- and assemblage-level variation in synonym counts across terrestrial vertebrates globally. We also explored how taxonomic uncertainty (i.e., instability in species identities) can affect latitudinal variation of diversification rates. The average number of synonyms was higher for species described earlier, better represented in scientific collections, with larger geographic ranges, occurring in temperate regions, and in areas of high biodiversity attention. In assemblage-level models, a higher average number of synonyms was associated ..., Synonym Data
We extracted the number of synonyms per species from the Catalogue of Life (CoL) Checklist (https://www.checklistbank.org/dataset/286246/download; Bánki et al., 2024) on 20 Feb 2024. The taxonomic backbone of the CoL for amphibians, birds, and mammals was based on the Integrated Taxonomic Information System (ITIS; https://itis.gov/), while data for reptiles were from the Reptile Database (http://www.reptile-database.org; Uetz and Hošek, 2021). The CoL dataset included columns for rank and status, with the former informing if a scientific name represented, for example, a species or subspecies, and the latter indicating whether names were accepted, ambiguous, or unique synonyms. Using these columns, we filtered our dataset to include only accepted (i.e., valid) species and unique synonyms (i.e., invalid names). Consequently, currently valid subspecies were not analysed, as they are classified neither as full species nor as synonyms. However, we conducted a sensitivity analysi..., , # Global patterns of taxonomic uncertainty and its impacts on biodiversity research

[https://doi.org/10.5061/dryad.5x69p8d9z](https://doi.org/10.5061/dryad.5x69p8d9z)

**There are 10 files associated with this paper:**

(1) our raw data, containing some predictors used in cross-species models (AdditionalVars.csv); (2) marine taxa as per the IUCN (marine_spp_IUCN.csv); (3) synonym information for currently valid species stored in a long format, including their description dates (Tetrapoda_BetaTaxonomy.csv); (4) phylogenetic trees for amphibians, birds, mammals, and reptiles stored in a zip file (phylo_trees.zip); (5) outputs from phylogenetic autocorrelation analyses (phylocorr_outs.zip); (6-7) spatial data (including predictor and response variables) needed for the assemblage-level analyses and mapping spatial variation in synonym counts (SpatialDataset.Rdata & gridShps.Rdata); (8) the R code to replicate the analyses performed in this work (Rcode_DarwinianShortfalls.R); (9) additiona...