Greetings all,
Scott Loarie asked me to comment on this thread so here goes.
To begin with, The Scorpion Files is not a professional site, it is not peer reviewed and the taxonomy reflected there is at the discretion of the webmaster. While I have no personal issues with him, and I believe he provides a service by maintaining a fairly up-to-date species checklist, he lacks the expertise to discriminate among the science he posts on his site. As such, his site provides equal, or more coverage of articles that have not passed rigorous peer review compared to others that have. This is epitomized by the classification he follows on the site, which was based on a thoroughly discredited analysis (for details see Prendini and Wheeler, 2005). Furthermore, much of what is posted on the site appears in homespun ‘journals’ with crony review, if any; other experts in the field (and I do not refer only to myself!) are never invited to review even for taxa where they are the most knowledgeable worldwide. Despite critiques in 2005, 2009 and again in 2016, there has been a proliferation of this problem in Arachnology as elsewhere (google ‘taxonomic vandalism’ for some examples). In short, do I recommend following The Scorpion Files? Perhaps it is useful as a species checklist, but the suprageneric classification promoted there should not be followed without a heavy dose of skepticism. Had I the time to maintain my own list, I would do so, but I don’t. I am way too busy with the science and my other duties (curation, expeditions and teaching) at the AMNH. Posting a higher classification to our AMNH lab website could be an option once our NSF Scorpion Phylogenomics grant (details below) is published, but that will not be for another two years or so as the project is still underway.
So, do I think the classification in Prendini and Wheeler (2005) is the answer? Not entirely, for several reasons. Firstly, the status quo classification presented there was an attempt to restore normalcy to a situation that was getting out of hand. For example, there has never, ever been doubt that Diplocentridae is a different family from Scorpionidae; there are numerous synapomorphies for Diplocentridae that are not shared by Scorpionidae, and vice versa (e.g., see Prendini, 2000) and many analyses to not even recover these families as a monophylum! However, the classification in Prendini and Wheeler (2005) was not suggested to be definitive and was expected to change. Secondly, it is 15 years old. In subsequent years, my research group and I continued researching the systematics of the order and revising the classification as we go. Various families were redefined along the way; take Hormuridae, for example. We now have a major NSF-DEB grant 1655050 to complete the job (for a summary, see https://www.nsf.gov/awardsearch/showAward?AWD_ID=1655050&HistoricalAwards=false). Other studies appeared in recent years, as mentioned in the thread. However, these studies apply an approach that is not without problems (e.g., a recent study based on the same methods suggests ricinuleids/hooded tick spiders are the closest relatives of horseshoe crabs!) giving pause to many arachnologists. Additionally, the taxon sampling in these works is heavily skewed and lacking lineages most experts consider critically important for rigorously reconstructing the phylogeny of an ancient group like scorpions. Unlike those studies, our approach will be based on a comprehensive sample of over 500 taxa and using a data source with a far better record for reconstructing deep level phylogeny (see recent publications on spider phylogeny by Hamilton and Bond, for example). We will also include organismal sources of data to test ‘traditional’ / ‘legacy’ hypotheses, not merely dismiss them out of hand. We expect many more changes in the phylogeny and suprageneric classification of scorpions just as we expect many well-known groups, already supported by copious synapomorphies, to be confirmed.
How does this affect iNaturalis? In my opinion, the prudent strategy, for the time being, is not a ‘one size fits all’ approach but rather to evaluate each case on its merits. I realize that may bother some, but science is never cut and dried. If this means applying Prendini and Wheeler (2005) for higher classification, with adjustments as needed, and The Scorpion Files for species checklist, with adjustments as needed, I support that.
Lorenzo Prendini
AMNH