Lepetodrilus elevatus

 
 

Figure 5 - Lepetodrilus elevatus (http://www.vetigastropoda.com)

L.elevatus (figure 5) is a small limpet species found within hydrothermal vent communities, typically on or Within the R.pachyptilia communities. Unlike with R.pachyptilia, L.elevatus has no     endosymbiont and relies on grazing particulate bacterial species present on rock surfaces and the Riftia tubes. Much like other limpet species a bicuspid tooth, attached to a radula, is used to rasp or scratch the surface layer of bacteria off the substrate and pass it into the mouth and then to the digestive organs.  

The species is small and streamlined, often occupying areas of high water speed (close to vent opening) shell morphology has been shaped to allow optimal feeding behaviour. Similarly inter-tidal limpet species shell morphology is well observed and plasticity in relation to shell shape/height and width is well documented. An increase in exposure, current in this case, will lead to a generally more depressed growth form (Hobday 1995). The current speeds of the vent outputs, which can range from 1.1 to 4.9 mm/s(Sarrazin et al 2009) have possibly shaped the shell morphology of this species., however there may be other factors such as predation effects. Due to the varying flow rates at each vent site and the spatial distribution of suitable locations, it is possible that at each separate vent community genetic distinction and eventual speciation could occur with L.elevatus. This is true for all species present in such communities, however due to the grazing feeding strategy of this species, as opposed to the endosymbiotic relationship seen in species R.pachyptilia it may be more affected by changes in flow rates and therefore changes in the microbial assemblage of a particular vent site. 

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