LONDON.- An international team of scientists have identified nine new species of butterflies using a combination of geographical, morphological and molecular analysis.

• AMISTAD, a new collections-based research project led by London’s Natural History Museum, is working on untangling the identities of a group of blue butterflies from South America.

• Naming new species will fill gaps in the tree of life, helping us to understand the different relationships between species and focus conservation efforts towards potentially threatened species.

Butterflies are some of the world’s most distinctive insects, but they can be surprisingly hard to tell apart. Some species copy each other’s appearance and share the same habitats, while others haven’t been seen in the wild in over a century. Now, using the latest advances in DNA sequencing, scientists are beginning to separate and name species once thought identical.

Christophe Faynel, a Hairstreaks expert who led the research paper said: “Thanks to the genetic revolution and the collaboration of researchers and museums in various countries led by London's Natural History Museum, century-old butterflies are now speaking to us. By comparing modern DNA with ancient DNA from historical specimens, we can resolve long confused and unnoticed species and uncover greater biodiversity than previously known.”

Using state-of-the-art ancient DNA sequencing, which can extract genetic material from a single butterfly leg smaller than an eyelash and over a century old, the international team of scientists working in the AMISTAD project co-led by Dr Blanca Huertas, Principal Curator of Butterflies at the Museum, investigated the subtle morphological differences between butterflies which are so similar in appearance that they were believed to be the same species. The genetic analysis confirmed the distinctions hidden in plain sight.

Dr Huertas said, "Some newly identified species were collected a century ago in habitats that might no longer exist, putting at risk the existence of these species and highlighting the urgency of this work."

The research paper, led by Christer Fåhraeus of the Fåhraeus Biodiversity Institute, focused on a group of Neotropical butterflies within the subfamily Theclinae (the Hairstreaks), one of the most species-rich groups. Analysing over 1,000 samples taken from collections around the world, the team combined DNA, morphology and geography to identify nine unnamed species in the Thereus genus, prioritising those at risk, as the tropical forests of South America experience rapid deforestation.

Previously, one group, the genena species was thought to contain only five species and four synonyms. Some of the newly named species, such as T. cacao, were named after the regions where the specimens were originally found. Other newly discovered, such as T. ramirezi, were named after a local scientist who have devoted their lives to these insects. The difficulty in distinguishing all these different butterfly species is perhaps best summed up in the newly named T. confusus which reflects the taxonomic puzzle the team faced.

Blanca continues, “The Museum cares of for five million butterfly specimens which makes up about 6% of the entire collection. With some of these specimens dating back to the 1600s, the Museum’s collections are an irreplaceable archive of life of our planet, allowing scientists and researchers to study species that may no longer exist, or are known to be at risk.”

Evolution of life and Genomics are two of our research themes that aim to study natural history specimens to reveal the past, present and future of life on Earth.

The paper Diagnostic male secondary sexual structures in the Thereus genena species group Lepidoptera: Lycaenidae: Theclinae) with the description of nine new species from Colombia, Peru, Brazil and French Guiana is available now in the journal Zootaxa.