Saturday, October 14, 2017

The Best of Cephalopods, The Worst of Cephalopods

At my first author event I fielded some excellent questions, such as "Where did cuttlefish come from?" and "How did your book get indexed?" I thought I was doing fine. Then an old friend lobbed this multi-pronged missile at me:

What is the best cephalopod? And, if it isn't the same, what is your favorite cephalopod? Also: what is the worst cephalopod?

Temporarily paralyzed by choice, I stammered out an appreciation of the query's depth and complexity. And then I rallied. Here are my answers, illuminated with additional reflection since that evening:

Rickard Zerpe/Flickr CC BY-SA-2.0
FAVORITE CEPHALOPOD: Pygmy Squid (Idiosepius spp.)

RATING: five stars, two tentacles, one glue gland

REVIEW: This adorable genus contains seven known species, all of which glue themselves to seagrass or seaweed with a mysterious and magnificent mucus. According to Mark Norman's Cephalopods: A World Guide, northern pygmy squid "feed on crustaceans . . . as large as themselves which they attack from behind and quickly eat into the heart." What's not to love?

FUN FACT: Scientists are working on turning pygmy squid into a model organism--like white mice and fruit flies!

LOCATION: South Africa and the western Pacific Ocean

John Forsythe/CephBase CC BY-NC-ND-3.0
OTHER FAVORITE CEPHALOPOD: California Lilliput Octopus (Octopus micropyrsus)

RATING: five stars, three centimeters

REVIEW: Elusive as it is, this species completely slipped my mind at the bookstore the other night. But it was the subject of my first-ever cephalopod research project, back when I was an undergraduate in Santa Barbara, and as such it will always hold a special place in my heart.

FUN FACT: Lilliput octopus eggs are enormous, up to one-third the length of an adult's body!

LOCATION: California, natch, both Alta and Baja. Within that range, they like to hang out in giant kelp holdfasts. After picking apart dozens of holdfasts, I can tell you that 99.9% of the arms you think might belong to a Lilliput octopus will turn out to be part of a brittle star.

Citron/Wikipedia CC BY-SA-3.0
BEST CEPHALOPOD: Vampire squid (Vampyroteuthis infernalis)

RATING: five stars, four weird fins, two snot-covered filaments

REVIEW: Where do I even start? Named like a nightmare, these animals are in fact peaceful blue-eyed grazers. They defend themselves by inversion and, if that doesn't work, with a dazzling light show. They like to keep scientists guessing--despite the "squid" in their name, their anatomy reveals that they're more like a kind of octopus. And they're very patient parents.

FUN FACT: Vampire squid are born with one pair of fins, then grow a second pair and eventually lose their "baby fins." (Does the "fin fairy" put money under their pillows?)

LOCATION: The Deep Sea--yeah, pretty much all of it

Martin R. Smith/Wikipedia CC0-1.0
WORST CEPHALOPOD: Nectocaris pteryx

RATING: five hundred million years old

REVIEW: Come on, did you really think I'd name any living cephalopod? Nectocaris was initially thought to be a kind of shrimp, but a controversial 2010 Nature paper re-interpreted it as a squid-like creature, complete with tentacles and siphon. Current scientific consensus, from a review by Björn Kröger and colleagues: "Nectocaris is contrary to our understanding of cephalopod evolution . . . A more likely hypothesis is that Nectocaris . . . developed a mode of life remarkably similar to cephalopods." Evolutionary convergence at work.

FUN FACT: Cephalopod paleontologists seem pretty tired of talking about Nectocaris, maybe don't bring it up--talk about ammonoids instead!

LOCATION: Burgess Shale, Chengjiang Biota, Emu Bay Shale

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