Why aren't Warbonnets and Cockscombs not Gunnels?

[Chevayea]

...and don't say "because they're pricklebacks"

Can someone explain to me in layman's terms whey these fish, which seem to be so gunnel-like, are not technically gunnels?

[Greg Jensen]

Good question. As is so often the case in taxonomy, there's no one single feature that says 'gunnel' or 'prickleback'- rather, there are several different combinations that indicate one or the other. For example, gunnels always have the dorsal and anal fins connected to the caudal (tail) fin; many pricklebacks do not. If a gunnel has pelvic fins it is made up of only one spine and one ray, while the pelvics of pricklebacks are one spine and 3-4 rays.
But many gunnels and pricklebacks don't have pelvic fins at all, and some of the pricklebacks that don't (e.g. black and rock pricklebacks) have their dorsal and anal fins connected with their tail. But these have 4 lateral lines while gunnels have one very short one or none (all our local ones lack a lateral line). Pricklebacks that don't have a lateral line have other features like the dorsal/anal/tail fin difference to separate them from gunnels.
Complicated? Yes, but fortunately for us the two groups just 'look' different- we see a gunnel and though we might not be sure of the species, there's just something about their head shape that says "gunnel". Pricklebacks are a much more diverse family both in form and lifestyle, with under-rock types (e.g. high cockscomb) and active, open bottom types (e.g., snake, bluebarred). I wouldn't be surprised if some future molecular analysis ended up splitting this family.

The usual question I get is "why aren't these things eels?" Eels belong to a very different lineage and, except for some very deep water ones we never see, aren't here in the Pacific northwest (so wolf eels aren't eels). True eels like morays have, among other things, a very weird flattened larval form called a leptocephalus.

[Grateful Diver]

Actually, wolf eels are blennies ...

... Bob (Grateful Diver)

[Chevayea]

Wow again, thank you Greg. I learn a ton every time you chime in.


So is there a group higher up on the ladder that they are all a part of? Are they all blennies (together with the Wolf Eel?)

[Greg Jensen]

Actually none of them are blennies. The level at which these guys are in the same grouping as blennies is in the Order Perciformes, which is a huge grouping (160 families) that has all sorts of fish (gouramis, swordfish, tuna, gobies, parrotfish, remoras, goatfish, and (surprise!) perch, among many, many others).

Gunnels, pricklebacks and wolf eels are all in the Suborder Zoarcoidei, which is filled out by several other local families: ronquils, eelpouts, prowfish, quillfish, wrymouths, and graveldivers.

Blennies are in the Suborder Blennioidei. The only Family in that suborder that is found locally are the Clinidae (kelpfishes).