Favoritos de ajustinfocus

Nudibranch Coryphella trilineata (northern form, about 10mm long) & look-alike amphipod Podocerus cristatus. Scanned from a 35 mm slide I took in the lab in 1984. I had found the specimens in close proximity to each other a few days earlier in the low intertidal at Middle Cove, Cape Arago, Oregon. The amphipod (and her recently hatched juveniles, visible at lower right when viewed large) are on a piece of the outer tube of the polychaete Pista elongata; the slug is on a piece of the hydroid Abietinaria.

Notice the white head tentacles of the slug and the white antennae on the amphipod. Here's what one form of the amphipod looks like in central California, where the southern form of O. trilineata ( with chromium orange on their rhinophores and cephalic tentacles) is prevalent: https://www.inaturalist.org/observations/1103734

Farther south, near Puerto Vallarta, MX, the amphipod lacks white lines, just like the abundant local aeolids (see Fig. 1f-h in paper here: https://www.researchgate.net/publication/282252603).

I’ve been assuming these little guys I see sometimes are just larval D. opalescens but I don’t actually know what all other species are in the area so want to look into a little more/hear from folks before specifying it down

Pointed out to me by a couple of birders, who suggested it had been “caught by the low tide". They moved it atop the rock.

Compellingly beautiful creature, the photo does not do it justice.

Seek could not identify, even to order.

Of the two species in these waters, looks much more like a Humboldt than an Opalescent.