After that last one, he not only disappeared beneath the sand, but did some wiggling under it until even the little mound left behind settled and was no more. Curious, I dug a little with my finger where we had seen him go down. He wasn't there. Where he went, I have no clue. But that's not the problem. The problem is one of ID.
Humann p. 79 lists two species that do this tail-burrowing thing. We initially identified this guy as the Catalina Conger, Gnathophis catalinensis, based on its appearance and the burrowing thing. But today we happened to be looking at this site:
metridium.com/monterey/fish/fish.html
and noticed that his picture of the Spotted Cusk-Eel, Chilara taylori, looks just like our guy. We hadn't considered that critter, because one of Humann's boldface ID features is the dark brown spots all over the body. Our guy doesn't have that. And from our pictures (and our memory) we're not sure whether he actually has the whisker-like dingfods under his chin, though it sure looks like it in a couple of our shots. The range on the Conger is a little iffy, depending on one's definition of "southern California," so I'm not sure. Either way, it was mesmerising to watch. We actually came upon a second one, but he did his burrowing thing before we could even think about getting the cameras into play.
Thoughts?
Thanks for the laugh!