Rediscovering a Darwin specimen

One of the most common questions during the last couple of weeks has been "how did you end up with a Darwin specimen?" The short answer is that I was the right person at the right time.

Here is the long answer: Insect systematists are very specialized scientists. I can identify most beetles to families. I can identify rove beetles (the family Staphylinidae) to the subfamily level and I can identify most Staphylininae (one of the subfamilies of rove beetles) to tribes and subtribes.  I can name almost all species in my taxonomic expertise (the subtribe Xanthopygina) but ask me about subfamilies of Orthoptera or Diptera and I have no clue.

Darwin's statue in BMNH

The Darwin specimen happened to belong to the subtribe Xanthopygina and I guess I was the best person in the world to tell if this was a new species and a new genus.

Back in 2008 my colleague Alexey Solodovnikov (University of Copenhagen) told me that there was a "Darwin Xanthopygine" in the Natural History Museum of London. To be honest, I think I just said "OK" and did not think much about it. Later, I even visited the BMNH and I failed to locate the specimen myself. The thing is, I was not really looking for it. My main goal during that visit was to photograph the vast type collection of Xanthopygina by Sharp. So I was really photographing types and paid little attention to unsorted materials.

Alexey later told me that he had found the Darwin specimen in a box of random unsorted Staphylinidae that included both new and historical materials. Realizing that this is a Xanthopygine, he transferred it to the unsorted materials of the genus Trigonopselaphus, as the best guess on where this specimen might belong. However, at this point neither Alexey, me or anybody at BMNH knew/realized that this specimen was considered lost according to Smith (1987)

Trigonopselaphus sp. 

Fast forward a few years and I have decided to revise the genus Trigonopselaphus (revision is in progress). Typically, one requests all described materials (types) and any unsorted/unidentified materials that belong in that genus. I requested materials from several museums, including BMNH. It was only then that I saw the Darwin specimen and quickly realized that it is a new genus and new species. But it would be another few months before I realized that the specimen was considered lost, while I compiled an inventory of all rove beetle specimens collected by Darwin.

The thing is, it takes a lot of time and preparation to be able to tell if a specimen you see is "new". If I had seen the Darwin specimen in 2004 or 2008, I would have been able to tell that is is a Xanthopygine, but I do not think I would have been able to recognize it as something new. 

Working with a Darwin specimen

Today a paper came out where I describe a new genus and species of rove beetles. The description was based on just two specimens, one from the Natural History Museum, London and one from the Museum für Naturkunde der Humboldt Universität, Berlin. We typically want to have more specimens before we describe a new species. However, I decided to go ahead with the paper for two reason (1) I have been visiting major (accessible) entomological collections for more than 12 years and I have not seen other specimens and (2) one of the specimens was collected by Darwin himself!

Below is a photograph of the holotype of the new species, Darwinilus sedarisi Chatzimanolis.

Image Copyright, The Natural History Museum, London.

The Darwin specimen was collected in 1832 and there are traces of (non water-soluble) glue on the ventral side of the specimen. You undoubtedly noticed that the specimen is "dirty".  I did not attempt to "clean" it, either physically or post processing (i.e., in Photoshop). I was both in awe and scared to death handling the specimen, so I really tried to minimize time spent handling it. To dissect the genitalia I followed the steam method described by Beulah Garner (curator of Coleoptera in the Natural History Museum, London). But I did not attempt to relax the mouthparts of move the legs, a standard practice on more recent specimens, as I did not want to press my luck.  

Here is a close up of the head, where all the dust is visible in exquisite detail:

Image Copyright, The Natural History Museum, London.

I know I could have very easily cleaned the specimen with a fine paintbrush. But in a specimen as old as this, who am I to say that the dust does not belong there, especially when it does not affect the specimen description?  In a later post I will write about how I stumble upon the specimen.