Last week I gave you this lovely little shell to try your hand at identifying:

It’s a specimen that was given to the Dead Zoo recently by a regular contributor to the collections and it’s particularly interesting because it might be the first record of this species in Ireland (this is currently being researched for publication by the donor, so I won’t give away too much detail).

What I will say is that this is one of the reasons species identifications can be very important, since our understanding of how species move around has implications for various aspects of society and you don’t want to make decisions based on bad information. If you don’t know what I mean by that, I’ll give you some examples.

Zebra mussels arrived in Ireland in the 1990s from the Black and Caspian Seas and they’ve bred prolifically. They altered freshwater ecosystems by filtering out plankton that other species depend on for survival and they form hard-to-remove clusters that foul boat hulls and block drainage and cooling pipes. They’re in North America too, and in 15 years they are estimated to have cost hydroelectric and water treatment plants somewhere in the region of $267 million to remove or defend against. It’s cheaper to defend against them than to remove them and fix the problems they cause, so you need to know what you’re dealing with.

Retrieval of zebra mussel-encrusted Vector Averaging Current Meter near Michigan City, IN. Lake Michigan, June 1999. Photo by M. McCormick, NOAA, Great Lakes Environmental Research Laboratory

Signal crayfish are another freshwater invasive species, this time from America, that have caused havoc in Europe because they are linked to the dreaded Crayfish plague (I kid you not). The American crayfish are resistant to this fungal(ish) disease, but they act as hosts and carriers. Ireland is the last country in Europe to be free of the invasive crayfish, but are constantly alert to the dangers they can pose to the native species.

Signal crayfish by David Perez, 2009

I should say that the many introduced species aren’t actually all that problematic. I’ve not heard that Little Owls (introduced by the Victorians for the cuteness) or Ring-necked Parakeets (escapees from aviaries) have had any significant impact in the UK. Still, it’s interesting to know when species turn up somewhere, especially if it reflects a change in the environment that may have other impacts.

Little Owl by Arturo Nikolai, 2008

Noble False Widow spiders were a harmless addition to the UK fauna back in 1879, that were quietly tucked down in Devon until the changing climate gave them the conditions to move further north. Now they’re up as far as Liverpool thanks to our warmer winters. Similar patterns are seen for a variety of Mediterranean species, demonstrating how we can track changes in our environment by keeping track of where and when certain species are found – but if you don’t get the species right, you don’t have good data. That’s part of why we have museums in the first place, to lodge ‘voucher’ specimens of recorded species so identifications can be double checked in the future.

Noble False Widow

Of course, I’m sure that you all appreciate the importance of getting identifications correct, since here you are reading my blog which tends to be all about identification! For those of you who recognised the mystery object as a scallop of some sort I tip my hat, but to Daniel Jones I offer congratulations – this is indeed a Calico Scallop Argopecten gibbus (Linnaeus, 1767) which is, as Joe Vans suggested, a juvenile. Normally these are found on the Atlantic coast of America. Well done! I’ll let you know more about the specimen when the paper is published.

More interesting dead stuff to come next Friday…