29 July 2006

Gallandia annularis: a snail above the clouds


The first mountain we surveyed during our recent expedition in Turkey was the 2500-m high Honaz. When we first reached the peak in our van, it was cool and rainy. Soon the clouds started to disperse; we could begin to see thru mist the vast scenery below us.

Our first station was right below the peak at 2510 m. At that altitude we could find only one tiny species of snail: Gallandia annularis. Their shells barely reach 4 mm in diameter.


The range of this species extends from the Iberian Peninsula thru the Alps, the Crimea, Turkey to Afghanistan (Hausdorf. 1995. Zool. Anz. 234:63). It is always found in mountainous areas. Widespread species like G. annularis with restricted habitats always raise the same question: how do they get from one suitable habitat to another?


Duane said...

So, how do they get from one suitable habitat to another?


I have some ideas, but I will save them for another post.

snailer said...

Here's some free thought...I think one possible reason there is a "constant" presence in a certain 'broken" distribution patterns, as exemplified here, could be attributed to this species having been present long enough to have "ridden" the habitat to it's current altitude...lol. Basically, what I'm thinking is that the snail was once more wide-spread, and as the landscape changed, it only survived in certain places. I don't have a clue if the geology in these places is related in any way, nor how long this species has been around. Just a thought...looking forward to your ideas when you post them. snailer

budak said...

Post Miocene cool-offs that allowed alpine/montane habitats to spread into the lowlands? What about biological dispersion, perhaps via egg-carrying birds?