Two species of wasp have been identified as belonging to a whole new genus endemic to the isolated Atlantic island of St Helena.
St Helena, a British Overseas Territory, is home to more than 400 species that can't be found anywhere else. However, the wildlife is under serious threat from development and invasive species.
The new wasp genus, named Helenanomalon in honour of its home territory, belongs to a family of parasitoid wasps - those that spend a part of their lifecycle on another organism that they eventually kill. However, little is known about the specific lifestyle of Helenanomalon since only a handful of specimens are known to exist.
One of the new wasps species, Helenanomalon bonapartei
The most recent specimens came to the Museum following a collecting expedition in 2006 that included the former Head of Entomology collections at the Museum, Howard Mendel. On re-examining the specimens, and a couple of others at the Musée de l'Afrique Centrale, Museum hymenoptera curator Dr Gavin Broad assigned them to two different species in the new genus:
These little wasps belong to the family Ichneumonidae, a huge family with over 24,000 described species in the world, but with only six species known to have made it all the way to St Helena. That two of these species form a genus not known anywhere else in the world is remarkable.
One of the new species, Helenanomalon bonapartei, is named after St Helena's most famous exile, whilst Helenanomalon ashmolei is named after Philip and Myrtle Ashmole, who have led recent work in exploring and documenting the fauna of St Helena.
Islands like St Helena often host unique organisms that have evolved in isolation for millions of years. However, these species are also extremely vulnerable to changes such as introduced predators and habitat loss.
St Helena used to be home to the world's largest earwig, the giant earwig, which reached over 8cm long and lived in deep burrows. Only a few specimens of the giant earwig have been recorded, and several scouting trips since the 1960s have failed to find any living examples. It is now considered extinct.
St Helena giant earwig, Labidura herculeana
Says Dr Broad:
The extinction of the giant earwig was a sad reminder of how vulnerable island endemics can be. There is still much work to be done on assessing just how unique the St Helena fauna is, and Philip Ashmole tells me that they have collected other potentially new genera of insects and spiders but the taxonomy of the groups concerned is difficult and there are few people with the expertise.
The native vegetation has been massively reduced by the usual pressures of introduced goats, non-native species, inappropriate agriculture, and so on. Restoring the native vegetation, particularly the seriously denuded forests, is the most important step in conserving the unique invertebrates.