Sluggish news on evolution from Journal of Conchology 2008 and 2009 and BBC 10 July 2008. A blind UK slug was nominated as one of the top ten new species by the International committee of taxonomists in 2008. The creature is a bright white, subterranean and carnivorous slug bearing close resemblance to the Testacella genus of slugs (also carnivorous) found in the UK. The slug is claimed to be evidence of an ‘altering’ species of introduced terrestrial slug, and therefore living evidence of evolution. The first specimen was collected in Powys (South Wales) from a graveyard in December 2004, according to an article in Journal of Conchology 40:103, October 2009. In October 2006 in Caerphilly another specimen was found. The following year another was observed by a gardener in Glamorgan, Cardiff. To date the slug has surfaced in a number of other Welsh districts including the town of Gorseinon north west of Swansea, Newport and Talgarth. One specimen has even been found across the Welsh/English border in Bristol.
In 2008 Ben Rowson at the National Museum in Wales and Bill Symondson an ecologist at Cardiff University named the slug Selenochlamys ysbryda or Ghost Slug, alluding to its ghostly white appearance, its nocturnal, predatory behaviour and the element of mystery as to its origin. The Welsh word ysbryda means ‘ghost or spirit’. One distinguishing feature in S. ysbryda, unique to the genus (amongst other anatomical differences) is the lack of eyes. Instead, the creature has what appears to be minute colourless vestigial eyes. In a similar Turkish specimen S.pallida the eyes appear normally developed. Symondson commented: “The lack of eyes and body colour could indicate the species evolved in a cave system”. However, in the Journal of Conchology, (2008), Vol.39, No.5 548, Rowson and Symondson state: “In colour and vestigial eyes, S. ysbryda resembles certain troglobitic (cave-dwelling) molluscs of the Caucasus but may simply be a deeply edaphobitic (soil-dwelling) animal”.
Editorial Comment: Our resident British slug aficionado Simon Terry comments: “Perhaps it’s time to ask some serious questions that don’t seem to have been asked. If the slug has lost both eyes and colour, is this evolution or is it merely degenerate change? Let’s first check some sluggish facts. First, we did not see S. ysbryda lose its eyes. Furthermore, the slugs Troglolestes sokolovi and Lesticulus nocturnus have what appear to be vestigial eyes, and like S. ysbryda are snow-white in colour. The semi slug Daudebardia nivea found in the same caves in western Georgia also has no developed eyes, and has white flesh. Therefore, if the eyes and body pigment have been lost this cannot be an example of evolution. It is far simpler to say the slug is probably degenerating, i.e. losing genetic information. But if it lives underground – it can survive without eyes and colour, but from now on it’s under threat from negative selection pressure whenever it comes above ground, day or night. We can also be very dogmatic that the slug never lost its eyes or went ghost white simply by living underground. Other well-known subterranean UK slugs possess very distinctive pigments – such as Testacella scutulum (yellowish body colour with dark spots); T. haliotidea (yellowish to dull creamy-white body colour with or without a scattering of pale brown spots); T.maugei (mid to dark brown body colour with paler sides and dark flecks above).
Degenerate mutations that cause loss of information are occurring all the time regardless of where a slug, snail, snake or Solomon Islander lives, simply due to degenerative cell processes and environmental hazards such as radiation and chemicals. Most of these degenerations you will never see since the creature never survives to pass them on. But some do survive, and from then the creature is stuck in a very restricted protective environment. The evolutionist likes to call this specialisation to fit a particular niche, when it’s really loss of the organism’s ability to cope with its previous much wider environmental range. Devolution is a better description of this change.
So here’s our predicted cold reality for slugs: Like other life forms since the flood of Noah’s day, degeneration is what we expect to find as evidence of the Biblical picture being the real history of planet earth, and it is what we actually observe and what we predict the future of slugs will be also”. (Ref. prediction, molluscs, mutations, malacology)
Slugs and snails have been in a recent project aimed at teaching evolution to school students. Simon Terry has written an article, The Snail Evolution Project, critiquing this project and explaining how research into snails supports Biblical biology. Download PDF here.