first things first. Chris’s note relates to the UKSI (2007) UK Community Dictionary
Whereas JoCs relates to the CoL 2008 the Global Community Index.
There are pretty frustrating anomalies in both - plenty of examples of synonyms in use and plenty of absences and some outright mistakes.
P. pholadiformis is, in some ways, a typical example of Dictionary issues where alien species, whether we consider them common or not, are not entered in dictionaries. The New Dictionary, when installed, will immediately be out of date. The latest addition to the UKSI (NHM) was three days ago.
Here is the Observation in question
https://www.ispotnature.org/communities/uk-and-ireland/view/observation/836361/ but it is one of many similar cases. Testers are having fun with dozens of them.
I can take the ID to the Test Site and see what happens - all WILL be well in this case but not, yet, plenty of others
To be fair, the New Dictionary is a wonder - it WILL be lovely to use but will still have issues and difficulties. It needs more testing before installing and the Curator needs more input from interested parties.
We need more use of the tags absent1 and taxonomy1 see Taxonomy issues PLEASE (now 2 years old)
There is a dedicated Forum thread here Proposed-dictionary testing where both the Curator and Coder respond; and a Project here https://www.ispotnature.org/communities/uk-and-ireland/view/project/835018/-the-new-dictionary-and-testing-news