If you’re not familiar with a stromatolite (and the similar thrombolite), it’s a unique microbial community with an ancient evolutionary history and extant in just a few small marine ecosystems, most notably Shark Bay in Western Australia. Unfortunately, per iNaturalist, there’s no good way to classify these observations other than as Bacteria or Cyanobacteria. I periodically see these identified on here as Australomedusa thrombolites—this is a hydroid associated with this ecosystem and the only taxon containing the word thrombolite.
It would be far better if there was a non-Linnaean category for this group. I understand that this is generally frowned upon here, but I also understand that exceptions are made on occasion. This warrants an exception. There needs to be a good way to categorize these observations.
Rather than flagging a taxon with this request, I thought I’d open it up to discussion here in the forums.