Sauropod Vertebra Picture of the Week

I have just made a series of fairly major edits to the in-progress Checklist for new zoological genera and species, and wanted to explain what’s changed and why.

The important change is that the Checklist no longer attempts to encompass the creation of families, nor of all genus-group and species-group names — only genera and species.  I took this painful decision after a lot of consultation with various people, here and by email, despite wanting the utility of the Checklist to be a broad as possible.  In the end, it became apparent that the attempt to include these other ranks could only result in the Checklist becoming much much longer and more complex, or leaving loopholes, or more likely both.

• The very terms “genus-group” and “species-group” are misleading to non-specialist taxonomists — they can easily be misunderstood as meaning “group of genera” and “group of species”.
• While the Code indicates that the only species-group ranks are species and subspecies, superspecies are fairly often used as well, and we don’t want to get into discussing such matters.
• Likewise, supergenera are sometimes used as well as genera, despite the lack of support in the Code.
• Conversely, the Code’s definition of genus-group names (see the Glossary) include things called “collective groups”, whatever they may be.
• Worse, the Code also talks about divisions, which are described in the Glossary, not particularly helpfully, as “(1) A rank that if treated as a division of a genus or subgenus is deemed to be of subgeneric rank for the purposes of nomenclature [Art. 10.4]. (2) A taxon at the rank of division.”  We just don’t want to get into that stuff.
• Discussion of subgenera and related ranks on the ICZN mailing list has resulted in disagreement even between taxonomy specialists on that list, over matters such as whether a subgenus can be used as the type genus of a family.  When even experts disagree, it seems a fool’s errand for the Checklist to try to tersely summarise the rules.

In short, I became convinced that trying to have the Checklist cover ranks other than genera and species opened up all sorts of cans of worms, and that the target audience — zoologists who are not taxonomy specialists — will get more value from a checklist that is more limited in scope, simpler to understand, and shorter.

As usual, comments are closed on this brief update — not to stifle debate, but because I want to keep all discussion together in one place: so please head over to the draft Checklist, read through the current version, and post any comments you may have.

I am optimistic that we are converging now on a version that is as simple as possible but no simpler.  Once we freeze in a few days, we will hopefully move to the next phase … which I’ll tell you about at the time.