I recently found an observation of a mollusk, which I identified as a gastropod, and which was later identified as a murex. It consists of a broken shell with no meat inside. I annotated it as dead, but couldn’t find any appropriate evidence of presence. It’s not a bone or a molt. How should it be annotated?
I think the only thing that those can be annoted as is dead. Maybe someday an Evidence of Presence: Shell annotation will be made or something.
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Is it a bone?
Don’t you get the option for “construction” ? That’s what we use for empty shells.
Staff have already indicated that “shell” is not really useful as a distinct annotation.
https://forum.inaturalist.org/t/what-annotation-for-mollusc-shells/54339/11
This is part of the organism so I don’t think this is right. It’s actually explicitly stated to be not used for shells.
https://help.inaturalist.org/en/support/solutions/articles/151000191830-what-are-the-definitions-of-inaturalist-annotations-#Evidence-of-Presence-(within-Life,-except-Plantae)
I just put organism.
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We don’t use the site in any sort of serious research capacity, but I’m surprised that Shell isn’t an annotation. Tridacna gigas shells are not Tridacna gigas organisms and if you’re working on conservation, then knowing the current range of living animals seems more valuable than where they have been historically.
For spider webs and egg cases to be constructions but mollusc shells aren’t seems rather arbitrary when they’re all made within the body of the organism with internal materials.
But shells are exoskeletons and therefore part of the organism, while webs and egg cases are made by the organism for a specific purpose. I’d say that’s a significant difference.
I agree that shells should be a possible annotation though - if “bone” is a separate option although it is part of the organism, “shell” should be possible as well.
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How would a shell annotation be different here than alive vs. dead?
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Would a shell annotation help for observations of other animals utilizing the ‘dead organism’? (e.g. hermit crabs)
Shell is on the list - also lots of comments on that long thread - about shells.
https://forum.inaturalist.org/t/lets-talk-annotations/627
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How should it be annotated?
Dead.
Canadian freshwater mussel identifiers use the Live/Shell observation field which has additional options for fresh and old shells.
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A desiccated insect is also mostly nothing but a shell (ie exoskeleton), just one made of chitin rather than calcium carbonate. The only difference is that when the soft bits of an insect decay away, the insect looks more like it did in life than when the soft bits of a bivalve decay away. If “dead” is good enough for the dried remains of an arthropod, I’d say it’s good enough for the dried remains of a mollusk too.
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Given that they are neither produced nor constructed by the crabs, I think that’s not really necessary. Pretty much all hermit crabs are going to have a shell anyway. If there’s some other particular reason for needing to annotate that and observation field should work.
Many photos of living shelled mollusks show only a very small part of the soft tissues, often none at all. This is especially true for the bivalves. In fact, generally speaking, dead bivalve shells are more identifiable than living ones because it is possible to see key features of the hinge plate which are not visible when the animal is alive. Living gastropods are more frequently photographed with some of the soft parts visible but those parts are usually less useful for identification than the shell itself. In some cases, the soft parts are obscuring the very shell features needed for an id.
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I realise that this is an uncommon observation, but “Dead bivalve, no shell” is an option.
Sure but that is quite rare (and that observation is casual anyway). We have only about 20 observations of nearly 10,000 that fit that in our Living Bivalves project. I think the fields associated with the project should accurately record this info if need be.
https://www.inaturalist.org/projects/living-bivalves
Unlike mollusk shells, spider webs and egg cases are not parts of a spider’s body. Mollusk shells are essential body parts; the animals cannot live (at least, not for long) without their shells. Calling the shell a “construction” would be like calling wood a construction made by trees but not actually part of the tree itself.
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