61 new beetle species reveal how little we still know about biodiversity

Published in the scientific journal Insect Systematics and Diversity, the study is the first comprehensive revision of the genus in China. The researchers documented more than 100 species, more than half of which are new discoveries.

Even large species can remain overlooked

What makes the discovery particularly remarkable is that these are not tiny or hidden organisms that are easy to miss. Platydracus beetles are relatively large, often several centimetres long, and many are brightly coloured or mimic wasps. Nevertheless, many species have either been overlooked in nature or remained unidentified in museum collections for decades.

– It is striking that so many new species can remain hidden among large and colourful beetles. It shows how little we actually know about biodiversity and that even highly visible species can still go unnoticed, says Associate Professor and curator at the Natural History Museum of Denmark, Alexey Solodovnikov.

He is a senior author of the study which was led his PhD student Qinghao Zhao together with postdoctoral researcher Aslak Kappel Hansen. The study was conducted in collaboration with researchers from the Ottawa Research and Development Centre and Shanghai Normal University.

Their work highlights a well-known problem in biodiversity research: the so-called Linnean shortfall – a term describing the vast gap between the number of formally named and described species and the actual number of species that exist in the world. Within the rove beetle family (Staphylinidae), to which Platydracus belongs, around 70,000 species are currently known worldwide. However, researchers estimate that the species known to science represent only 20–25% of the total number of rove beetle species in nature.

Insects are by far the most species-rich animal group on Earth. Researchers have described around 925,000 insect species, but the total number is estimated to exceed five million.

Old descriptions and new methods

The study also shows that even previously described species are often insufficiently documented. Many species have only been known from one or very few old records with limited information about their distribution, variation, and ecology.

As a result, the researchers not only described new species but also corrected earlier mistakes in several cases, where species had been incorrectly identified or described based on insufficient knowledge according to modern taxonomic standards.

– Many species were originally described on a very limited basis. With more collected specimens and modern methods of examination, we can now test and refine earlier species delimitations while adding new species to nature’s mosaic. This gives us a much more accurate picture of biodiversity, which is crucial both for our understanding of nature and for our ability to protect it, explains Alexey Solodovnikov.

The researchers combined classical morphological analyses with DNA barcoding and demonstrated that species can, in some cases, vary considerably in appearance while sharing the same DNA markers – or vice versa. This points to the need for more integrated approaches in future biodiversity research and for revisiting “known” species when their newly discovered relatives are identified.

A foundation for future biodiversity research

The study provides an important foundation for future research on Platydracus in China and the rest of Southeast Asia – large regions containing some of the world’s most important biodiversity hotspots. At the same time, it highlights how limited our knowledge still is, even when it comes to relatively large and easily recognisable species.

Even for many named species, their distribution, ecology, and natural history remain largely unknown. In this study, several species are known only from a few specimens collected at single localities.

The mapping of biodiversity is therefore far from complete. On the contrary, the study demonstrates that even well-studied groups still contain a large number of unknown species — and that the work of describing and understanding them remains essential for both research and future nature conservation.

Publication

Integrative taxonomic revision of the rove beetle genus Platydracus of the Chinese fauna
Publicized in Insect Systematics and Diversity