Some of the Museum’s invaluable butterfly reference material, previously only accessible to a handful of scientists, has been released onto the Museum’s Data Portal. Over 90% of these specimens were designated as types in the 21st Century, but this is the first time that images of many of these species have been freely accessible to the global community.

My type on paper

When scientists describe and name a new species, they aren’t actually describing every individual that belongs to that species. Instead they select one or a few specimens with ‘typical’ characteristics representing a species to write a detailed description. These name-bearing specimens are known as types, and are used as a reference when identifying and grouping other individuals into that species.

A type bears not only a name, but a big responsibility. If you want to identify and name specimens you have observed or collected you need to look to the type (or an illustration of it) and compare the key characteristics that make that species unique and different from others. For this reason, types are arguably some of the most important specimens in a collection and a priority for digitisation projects.

Recently, the Museum’s butterfly types have been separated from the main collection into a new seperate collection, making it easier to find, use and reference them. To make these types even more accessible, it was also decided that this collection would be digitised and made available on data.nhm.ac.uk – separate curation first makes digitisation of these collections much more efficient, removing the need to ‘pick and choose’ from many different collections drawers.

Vital statistics

We digitised 1000 specimens, covering 220 species. These specimens were collected from 46 countries, representing all continents. The oldest type in this project was designated in 1939 and the newest in 2017.

What’s in a name?

Digitisation isn’t just about capturing an image of a specimen. Before these butterflies were ready for their close ups, extensive curatorial work was needed to prepare the collection, ensuring that each specimen is associated with the correct taxonomic information (e.g. the species and genus names are correct).

Among these specimens, we found various examples that illustrated the importance of this digitisation project. For example, six specimens used to describe the species Cacyreus niebuhri, an African species, in 1982, had no identification labels or registration information when they were found in the mixed collections – they had lost their name!

As part of this project, an investigation was mounted to discover the true identity of these six butterfly types. Fortunately, information about when and where the specimens were collected was available on the labels pinned underneath each butterfly, with a small label from the author stating they were part of a type series.

The specimen labels indicated that they were collected in the Republic of Yemen by “T.B. Larsen” in 1980. A former Scientific Associate of the Museum, Dr Torben Larsen was a world renowned expert on butterflies of Africa and wrote many books on the subject. A search of his name, along with the collection event details from the specimen labels, threw up the only book on butterflies written from the area and at the time of the species’ description in 1982. Although the book is currently out of print, “The Butterflies of the Yemen Arab Republic” is available at the Museum library and had been digitised so we were able to search the text. As we knew the family that these butterflies belong to, we were able to find the description and images of the mysterious specimens and their name. Cacyreus niebuhri – named for the 18th century Danish topographer Carsten Niebuhr, one of five men who took part in an ill-fated expedition to Yemen that saw him as the sole survivor.

Further searching online revealed that Larsen’s book is the only place that any images of this species can be found, including recent revisions and websites describing the species. The images included in the book are of a quality that makes it hard to identify important diagnostic characteristics, and resolution is even lower in the digitised copy of the book. Type specimens are the reference material for any specimen identification, so without access to a detailed image, identifying anything as C. niebuhri becomes extremely difficult, leading to misidentifications or no identifications at all. The quality of the images that we have released on data.nhm.ac.uk help to address this problem.

The Museum’s image of the paratype specimen of Cacyreus niebuhri

The only reference image available for C. niebuhri before this project.

Above left: The Museum’s image of the paratype specimen of Cacyreus niebuhri. Right: The only reference image available for C. niebuhri before this project.

Sharing is caring

By sharing data about our specimens we provide a resource that can be used by the scientific community and the public in a number of ways. One of the reasons museum collections remain such an important scientific resource is because they provide a window into a species’ past, allowing us to compare them over time and space, revealing if and how their distributions have altered with the rapidly changing environment. This all starts with being able to give members of the same species the correct name, so that the comparisons are meaningful.

C. niebuhri, a member of the Lycaenidae family, is endemic to the Republic of Yemen, only occurring on the upper reaches of the wetter mountains of that country. These mountains form part of the Arabian Peninsula ecoregion, a region that supports thousands of unique plants and animals and one that is increasingly under pressure from deforestation and soil erosion. Any work aiming to mitigate these pressures on endemic species needs first to know what species occur in this area so that their populations can be monitored. Comparing individuals currently in the area to a name- bearing type specimen should make this easier.

Dingana alaedeus is another example of an endemic species that the Museum holds type material for. Commonly known as the Wakkerstroom widow, this butterfly is found only in South Africa’s high altitude grasslands at elevations of about 2,000 meters and classified as “Near Threatened” during the 2013 Conservation Assessment of Butterflies for South Africa. Similar to the previous example there is little information relating to this species online, with the same single image being used on several different online resources. In fact, for most of the 220 species we have digitised during this project the images that we have uploaded to the Museum’s Data Portal are the first and only images to be easily accessible online.

Unlocking the Museum’s collections and making them available to all is the mission behind many of our digitisation projects and is one of the Museum’s strategic priorities. There are over 1.5 billion natural history specimens in collections around the world. They have the potential to play a critical role in addressing the most important challenge that humans face over the next years: how to map a sustainable future for ourselves and our changing planet. To see the butterfly types digitised during this project, and over 4.3 million other specimens, visit the Museum’s Data Portal.