Bristlenose scales/plates query

[Smj83]

Found this strange item in my tank tonight. Never seen anything like it before but I can only presume its came from my L144 as its hard and has a wee node on one side that looks like it's broken off. The only thing is I can't see any missing plates or scales on her. She doesn't have any abrasions or wounds.
Can anyone confirm this for me and is it anything to worry about. Going to do a water change tonight to be on safe side

[TropicalFishForums]

[Suelo]

Might be a bit of a random suggestion - do you have any nerite snails?

One of my nerites passed away, & their trapdoor bit separated from the shell & it looked quite like that.

[Smj83]

That makes sense. I had a zebra nerite that passed away about a month ago. It was at least 2 years old which I thought was quite good. The size would be about right as well. Thanks suelo. Puts my mind at rest. Just seen the colour and presumed it was the lemon bristlenose

[Suelo]

I think my nerite was a zebra too. I think my shrimps found him, as one day I just saw the empty upside down shell, with a little piece like that close by. I guess it is the trapdoor bit as it was right next to the shell - if I had seen it on its own I don't think i would have made any association.