Saint Helena is a small island in the Atlantic Ocean that is a very long way from any continent. It is approximately 1850 km from Africa, and about 3290 km from South America. It is only 16 km by 8 km in size, and the highest peak is 818 m above sea level. It is the place where Napoleon was exiled, and where he lived the last five and a half years of his life. It currently has a population of about 5,000 people, and is a British Overseas Territory.
And it is a place with an endemic radiation of extremely odd bembidiine carabids. I have dreamed of going there to collect some for DNA studies, to find out where they belong in the bembidiine evolutionary tree. They are currently classified as genera separate from Bembidion.
Here is where Saint Helena lies:
I’ve looked into traveling to Saint Helena, and it is not a trivial undertaking. There is no airport in Saint Helena (although one is under construction with a scheduled opening in 2016), and the typical route is to fly to Capetown, South Africa, and from there take a Royal Mail Ship to the island, a sea journey of five days (one way).
The flora and fauna of Saint Helena has many endemics, including all but one of the bembidiines. In addition to the widespread Bembidion mixtum, the bembidiine fauna consists of only 12 described species, but these are fantastically diverse. Here are three of the species:
Some of these simply don’t look like bembidiines. The oddest one isn’t shown here – it is Endosomatium megalops, whose huge head is vastly out of proportion to the rest of its body.
Unfortunately, some or all of these may now be extinct. The introduction of invasive plants and animals, including goats and Homo sapiens, has destroyed much of the habitat in which these beetles lived – the special forests on the island. Howard Mendel, as part of his month-long survey in 2005-2006, sought these beetles, and only found a single specimen of an undescribed species. As Mendel, Ashmole, and Ashmole note in their survey report (available here), “we failed to find any of the twelve known species in these three endemic genera. They are of ancient lineage and closely associated with the cabbage tree / Tree Fern cloud forest on the Peaks. Their survival is of grave concern and in serious doubt. ”
This has made me rethink going to Saint Helena, in part because I think more work needs to be done re-establishing the beetles’ forest habitat before any more collecting is attempted. Instead, I have focused my attention on seeing if I can extract and sequence DNA from some of the pinned specimens already in museums. To that end, I borrowed specimens of three species from the Royal Museum for Central Africa in Tervuren, Belgium. I’ve extracted DNA from one of each of these. The DNA from one of them, a Pseudophilochthus nubigena, looks as if it will be of high-enough quality to allow us to obtain sequences using next-generation sequencing. And, in fact, we have PCR products for 500 bases of 28S and 450 bases of the wingless gene.
In advance of the next-generation sequencing, we will be sending the PCR products off to be sequenced, and hope to have results within a week. We should have the first information then about where at least that one species falls.
And so, I will make the following prediction: the Saint Helena species are simply highly derived Bembidion, and should not be treated as separate genera. They form a single, endemic clade (to test this, sequences from more than one species will be required). My first guess is that they belong to the Bembidion Series (Maddison 2012), perhaps near the Antiperyphanes Complex of South America or the Ananotaphus Complex of Australia, New Zealand, and Hawaii. My second guess is that they are in the Philochthus Complex. These guesses are based more on gestalt than a careful character analyses; the dominance of the Bembidion Series in the southern hemisphere fauna also sways me.