Gastropod ID?

[Nano sapiens]

Gastropod of some sort. Small limpet-like shell (~3/8"), animal has B/W antennae and a long black protrusible forked tongue. From what I know, true limpets have a rasping radula so this is something entirely different. In the 4 months that I've had it in my tank, it has never moved from the shown position on the hermit's cone shell. The 'tongue' seems to probe the rock and sand whenever it can reach them.

Any ideas?

 

[vetteguy53081]

Appears to be a limpet

 

[Nano sapiens]

Thanks for the input.

The limpets that I know of are all mobile and rasp algae/biofilm from rock surfaces with a radula. This animal hasn't moved in 4 months and has a long flexible tongue. After further study on limpet types, some are detritovores and some are carnivores. Many tend to return to a home location after feeding or when under stress. The one I have here seems to be an extreme homebody

 

[king aiptasia]

such a strange limpet, looks like an elephants trunk lol

 

[Nano sapiens]

such a strange limpet, looks like an elephants trunk lol

Yeah, I can't find anything on line that's like it.

 

[Nano sapiens]

Ok, so I think I can wrap this up...

Personal observations:

1. I've now seen the limpet pull back it's two black forked tongue projections and reveal a bright white radula made up of two rows of teeth arranged in a tread-like pattern.
2. Over the last month or two I've noticed severe rasp marks, primarily on my other hermit's shells. So now I know what has been doing this, namely the radula of this limpet! The hermits often group together when food is present and this is very likely the time when the limpet scrapes the other hermits' shells.
3. The limpet had never moved from it's position on the cone shell. I believe the reason is that it has no reason to since the hermit takes it all around the tank anyway

From the Internet (http://www.snorkelstj.com/limpet-snail.html):

It is extremely difficult to even identify this snail to an Order or Family as it may/may not be a true limpet. Here's why:

Limpet Snail is a common name for a variety of snails that grow a conical shaped shell. There are True Limpets and false limpets, some of which are the keyhole limpets. Limpets are mollusks. Mollusks are second in species diversity only to that of insects.

The common name "limpet" also is applied to a number of not very closely related groups of sea snails and freshwater snails (aquatic gastropod mollusks). Thus the common name "limpet" has very little taxonomic significance in and of itself; the name is applied not only to true limpets (the Patellogastropoda), but also to all snails that have a simple shell that is broadly conical in shape, and either is not spirally coiled, or appears not to be coiled in the adult snail. In other words, the shell of all limpets is "patelliform", which means the shell is shaped more or less like the shell of most true limpets. The term "false limpets" is used for some (but not all) of these other groups that have a conical shell. Thus, the name limpet is used to describe various extremely diverse groups of gastropods that have independently evolved a shell of the same basic shape (see convergent evolution). And although the name "limpet" is given on the basis of a limpet-like or "patelliform" shell, the several groups of snails that have a shell of this type are not at all closely related to one another.

 

[Nano sapiens]

There are a number of loose ends here to this seeming simple story that got me thinking. Most compelling is why doesn't this limpet leave the shell it calls home to forage and then return home afterward? Even when the hermit crab molts and the shell is stationary for days, the limpet doesn't budge. The easy answer is that 'It has figured out that it doesn't have to', but I think that's attributing too much intelligence to a gastropod.

The more I think about it, the more I suspect that this particular species may have evolved to be a permanent resident on mobile snail shells. Because if it were to leave it's home to forage, as many limpet species do, it might never find it again as the snail (or later the hermit crab) would likely have wander off. If I were to hazard a guess, it probably seeks out a host in it's early larval stage, finds enough nourishment by grazing whatever is on the shell's surface and then settles down into an advantageous permanent home location. The long proboscis would then be an adaptation that allows it to feed by scraping any surface that the snail/hermit comes into contact with (I see evidence of this scraping on other shells and even occasionally the live rock). Limpet mating might then occur when the snail or hermit crab encounters another of it's kind with an attached limpet.

While pure conjecture on my part, considering that there are over 62,000 described gastropod species (estimated to be ~150,000 total), having one, or a few, that have developed this unique lifestyle seems plausible. Maybe, just maybe, this one might be a limpet species that is new to science

 

[king aiptasia]

There are a number of loose ends here to this seeming simple story that got me thinking. Most compelling is why doesn't this limpet leave the shell it calls home to forage and then return home afterward? Even when the hermit crab molts and the shell is stationary for days, the limpet doesn't budge. The easy answer is that 'It has figured out that it doesn't have to', but I think that's attributing too much intelligence to a gastropod.

The more I think about it, the more I suspect that this particular species may have evolved to be a permanent resident on mobile snail shells. Because if it were to leave it's home to forage, as many limpet species do, it might never find it again as the snail (or later the hermit crab) would likely have wander off. If I were to hazard a guess, it probably seeks out a host in it's early larval stage, finds enough nourishment by grazing whatever is on the shell's surface and then settles down into an advantageous permanent home location. The long proboscis would then be an adaptation that allows it to feed by scraping any surface that the snail/hermit comes into contact with (I see evidence of this scraping on other shells and even occasionally the live rock). Limpet mating might then occur when the snail or hermit crab encounters another of it's kind with an attached limpet.

While pure conjecture on my part, considering that there are over 62,000 described gastropod species (estimated to be ~150,000 total), having one, or a few, that have developed this unique lifestyle seems plausible. Maybe, just maybe, this one might be a limpet species that is new to science

interesting thought, im gonna screencap it for my reference cause it is hard to explain why an animal would need such a tremendous proboscis. Some mollusks have extremely low nutritional requirements and may not have to move out of an area more than 4 square inches their entire lifespan to get all the food they need. but in your video he moves pretty fast, id kinda like to see more of that in action cause it is really cool and unique