Flag for Taxon: Chestnut Clam (Astarte castanea)
| Flagger | Content Author | Content | Reason | Flag Created | Resolved by | Resolution |
|---|---|---|---|---|---|---|
| clauden | Chestnut Clam (Astarte castanea) |
subgenus is now full genus, so is: Isocrassina castanea |
Feb. 19, 2024 00:43:13 +0000 | thomaseverest |
See comments |
Comments
Swap drafted but not committed. Thoughts from @gparosenberg @susanhewitt @tfrench @ipat?
I support the taxonomy recognized by WoRMS.
Looks like we should maybe also split Astarte?
Quickly reviewing present observations, I found only a few as Astarte sp. that could be considered as castanea (now updated). It is much more common to report castanea-like kinds at the species level, while the other species are reported as Astarte sp.
I agree that we should follow WoRMS in this case.
@clauden So you're saying these shouldn't even be IDed to species anyway?
@thomaseverest, I was musing about your comment to split. The species is to change, but does not affect the label of genus Astarte. I was thinking about consequences for those tagged as genus Astarte sp.--if these would have to go to family Astartidae because some could be of Isocrassina castanea. It looks like none of I. c. are presently tagged as 'Astarte sp.', So, I suggest continuing to use genus Astarte won't likely be a issue for observations because that name is used for the the several kinds of ribbed shells, unlike I. c.
This taxon swap will have roughly 60 unintended disagreements, where there is an ID of Astarte that will be conflicting with the resulting ID of Isocrassina. See here:
https://www.inaturalist.org/observations?id=104223874,104223952,106644791,107484904,108606431,112595231,126657723,133647378,133744418,135109023,139227990,140817703,168171840,169379189,173662991,180797157,191723971,195032617,49567944,52525077,53368999,69736354,72948076,72948259,80019628,84718548,87991796,87991962,87992022,88032511,88448272,89197703,92431611,93264849,95853901&place_id=any&verifiable=any
Splitting Astarte would bump IDs of Astarte to Astartidae, so there are no longer unintended disagreements. If Astarte and Isocrassina are geographically isolated, then we can carry over the necessary IDs automatically from Astarte to Isocrassina where applicable.
All* of iNat's IDs for castanea are in North American waters from New Brunswick and Nova Scotia south to North Carolina. Could there be an atlased taxon split for Astarte s.l. only applied to that area?
I'm probably guilty of some of those IDs where I wasn't sure which species but knew that it wasn't something else (often Corbicula).
*Except two in Europe that are wrong IDs:
https://www.inaturalist.org/observations/126327068
https://www.inaturalist.org/observations/119846223
Those two won't be affected by the change.
All current observations of Astarte castanea would become Isocrassina castanea.
Looking quickly, does not look as if any of the current observations of Astarte sp. could be Isocrassina castanea.
If any of Astarte sp. were to be confirmed to species, then would be one of the Astarte species or Isocrassina castanea.
The family Astartidae would be necessary--if an observation was just in name (i.e,. OBIS records). Similar to Colus spp. that needed to become family Buccinidae because now several genera. But because of photos, there is the possibility to resolve to species, and therefore the correct genus-species combination could be applied.
Agree that a geographic split could be done--all of castanea should be in NE North America, as mentioned above.
Is it necessary? Since the confusion may be temporary when reviewing photos between the 2 kinds--Astarte spp. and Isocrassina castanea. The European ones were obvious, found, and corrected.
All current observations of Astarte castanea would become Isocrassina castanea.
This is not exactly correct. About 60 of those IDs will conflict with an existing ID of Astarte, which means the display taxon on dozens of observations will be Astartidae. If there were 3+ IDs of Isocrassina on these observations a split wouldn't be necessary, but that's not the case.
This would be an easy split where IDs of Astarte in NE NA are changed to Astartidae. No IDs anywhere else in the world would change.
@thomaseverest, thanks--though I do not yet understand. Agree it would be an easy split, but why is it necessary?
Any observation as Astartidae would be Astarte sp. (several difficult species), or the new genus with castanea. The new genus with castanea could be evident, e.g., with smooth shells, so they are unlikely to be recorded as either Astarte or Astartidae. So, all remaining Astartidae observations in NW Atlantic (after excluding the smooth I. castanea) would be...Astarte sp. Is that correct?
That is theory. In practice, in the link you show above for 60 affected IDs, right now I see only 33 records, 31 named as castanea, and 2 that look like castanea but displayed as Astarte sp. due to differing opinions. If the genus were to be updated for castanea in iNat, then automatically these 2 Astarte sp. observations would show up as family Astartidae, until someone else reviewed and updated them to castanea (or not).
https://www.inaturalist.org/observations/107484904
https://www.inaturalist.org/observations/49567944
Am trying to follow the rationale for how revisions are decided, to learn for future decisions, and for my work with groups in Canada, so thanks again for this discussion!
Ah, my apologies, I now see in part. I noticed that many observations currently display the name Astarte castanea. But all of those that are not yet at ResearchGrade level would be affected by the genus change (go to Astartidae), and not the new genus as I had expected. Unless there were several IDs supporting the new name, as you said. I think that would be fine--would encourage folks to review and update these cases where possible, while not affecting other Astarte spp. observations. The reason I rue the split to family is because, it seems to me, many records of 'Astarte sp.' will remain at genus (difficult to ID), and yet never be I. castanea, so pushing to family would be unfortunate because it suggests that the genus level is not possible for the remaining 'Astarte sp'. However, the geographical split would be limited in area, not many impacts. And it may make us to try do better at ID, based on geography and with good folks like @ipat!
OK I will just commit the swap for now then. Bumping IDs to family doesn't indicate that observations can't be IDed further, it just removes unintended disagreements. Astarte + Astarte castanea = Astarte castanea, but after the swap Astarte + Isocrassina castanea = Astartidae. So these are at family anyway. Splitting would make these observations Astartidae + Isocrassina castanea = Isocrassina castanea.
Given that another species in the same region has also been moved to a new genus, there are more possible unintended disagreements that could be fixed by this single split. But it looks like it is just this observation:
https://www.inaturalist.org/observations/14535109
But if you think IDers can fix this on their own, then it is not strictly necessary.
https://www.marinespecies.org/aphia.php?p=taxdetails&id=156744
Pouwer (2010) p. 33 "The absence of prominent ornamentation is a major morphological feature, clearly indicating this taxon as an independent genus. Type-species is Isocrassina castanea (Say, 1822) (Recent, eastern North America)"
https://natuurtijdschriften.nl/pub/541741/CR2010007001002.pdf