So, reading Science Daily*1, as I do from time to time, I picked up on an article about a very early jawed vertebrate. The newly identified critter is a late Silurian (Upper Silurian) fish that appears to date to Lau event and/or the period of recovery immediately after the Lau event (423 Mya).
None of that particularly escapes me. However, the article, which you can see here, included a graphic of the holotype fossil, and the graphic’s caption puzzled me. Perhaps you, dear reader, can help me out of my befuddlement.