pharyngula

Friday Cephalopod: I succumb to peer pressure and will mention Octopolis

pharyngula — Fri, 22 Sep 2017 18:10:22 +0000

Friday Cephalopod: I succumb to peer pressure and will mention Octopolis

Wow. Every person on the planet saw one version or another of this "Octopolis" story and had to send it to me. It was the subject of a Friday Cephalopod a year ago, you know.

Apparently, this is the second octopus city discovered, which is interesting -- they're exhibiting more complex social behaviors.

However, I have two complaints.

A lot of the stories are describing Octopolis/Octlantis as "gloomy". Why? Is it because the inhabitants aren't swimming around with toothy grins? The cephalopods look quite normal to me.
A more serious complaint, about this quote:

The discovery was a surprise, Scheel told Quartz. “These behaviors are the product of natural selection, and may be remarkably similar to vertebrate complex social behavior. This suggests that when the right conditions occur, evolution may produce very similar outcomes in diverse groups of organisms.”

Nope. You don't know that. There's no evidence and no reason to think this behavior is the product of natural selection -- quite the opposite, actually. It looks to me like the spontaneous emergence of a novel property of octopus behavior in an unusual and fortuitous environment.

pharyngula Fri, 09/22/2017 - 14:10

Friday Cephalopod: we all float down here

pharyngula — Fri, 15 Sep 2017 19:12:20 +0000

Friday Cephalopod: we all float down here

Pale, drifting quietly, long grasping arms, cold and anoxic…we all float down here.

Yes, I'm going to go see It this evening. It won't be half as creepy as the reality of the dark deep, though.

pharyngula Fri, 09/15/2017 - 15:12

Friday Cephalopod: Reflecting my current mood

pharyngula — Fri, 08 Sep 2017 17:17:35 +0000

Friday Cephalopod: Reflecting my current mood

Stephanie Bush

pharyngula Fri, 09/08/2017 - 13:17

Friday Cephalopod: Sinking blue

pharyngula — Fri, 01 Sep 2017 19:26:44 +0000

Friday Cephalopod: Sinking blue

I think it's a portrait of my mood right now.

pharyngula Fri, 09/01/2017 - 15:26

Friday Cephalopod: Undead Squid Penis

pharyngula — Fri, 25 Aug 2017 09:03:53 +0000

Friday Cephalopod: Undead Squid Penis

First, a little background:

When squid mate, a male transfers its sperm to a female enclosed in complex structures called spermatophores. These are accumulated in the spermatophoric sac, a storage organ inside the mantle cavity, before ejaculation through the penis. Squid that spawn in shelf waters and epipelagic waters of the open ocean usually have short penes hidden completely inside the mantle. Males pick the ejaculated spermatophores from inside their mantle with a specially modified arm called the hectocotylus, to transfer them to the female. Females spawning in shallow water have special places for spermatophore attachment on the body, both externally (skin ring around the mouth, and back of the head) and internally (oviducal gland openings near gills) (Nesis, 1995). As female squid lack a vagina, the use of a highly articulated arm (hectocotylus) for transfer and placement of spermatophores is more precise than by means of the comparatively poorly articulated penis.

So male squid have penises deep in their mantle. Many species have short penises, and they also have a specialized arm, the hectocotylus, that they use to reach in to their own mantle to scoop up ejaculate and then place it in the appropriate place in a female.

Other species lack the hectocotylus, but instead have a long penis, as some investicators discovered. They are also capable of erections, which was a surprise.

A mature moribund male of the greater hooked squid Onykia ingens (Smith, 1881) (38.5 cm mantle length, 1180 g body mass) was caught on the Patagonian slope south of the Falkland Islands (July 2006, 53°20′S, 59°31′W, 1050 m depth). When the mantle of the squid was opened for maturity assessment during processing of the catch onboard, the penis of the squid, which previously had extended only slightly beyond the mantle margin, suddenly started to erect. It became rigid and quickly elongated to 67 cm total length, almost the same length as the whole body of the animal (mantle, head and arms; Fig. 1). Immediately after elongation, several spermatophores were ejaculated from the penis tip.

So not only do they have penises capable of erection, they can get erections when dead and partially dissected, which means I can now show you a zombie squid dick pic.

Mature males of deep-water squid Onykia ingens with cut-open mantles showing non-erect (A) and fully erect (B) penes.

(blame Tommy Leung)

Arkhipkin AI, Laptikhovsky VV (2010) Observation of penis elongation in Onykia ingens: implications for spermatophore transfer in deep-water squid, Journal of Molluscan Studies 76(3):299–300.

pharyngula Fri, 08/25/2017 - 05:03

Friday Cephalopod: Squink

pharyngula — Fri, 18 Aug 2017 18:11:29 +0000

Friday Cephalopod: Squink

If you've ever wondered what squid ink is made of, here's your answer:

Generally, cephalopod ink includes melanin, enzymes related to melanin production, catecholamines, peptidoglycans, free amino acids and metals.

But mostly melanin. And mucus.

pharyngula Fri, 08/18/2017 - 14:11

Mary's Monday Metazoan: Son of Spongebob

pharyngula — Mon, 14 Aug 2017 22:26:09 +0000

Mary's Monday Metazoan: Son of Spongebob

The sequel is going to go a bit dark: this is a deep ocean sponge. It's dark and ominous, and it's also carnivorous, with sticky spines for capturing and killing passing animals.

I think that thing has been waiting for me in a lot of my nightmares.

pharyngula Mon, 08/14/2017 - 18:26

Friday Cephalopod: that reminds me -- it's lunchtime

pharyngula — Fri, 04 Aug 2017 14:58:24 +0000

Friday Cephalopod: that reminds me -- it's lunchtime

Time to forage.

pharyngula Fri, 08/04/2017 - 10:58

Friday Cephalopod: Tomorrow is an open house at MBARI, and I have to miss it

pharyngula — Fri, 28 Jul 2017 15:34:03 +0000

Friday Cephalopod: Tomorrow is an open house at MBARI, and I have to miss it

You Californians have no excuse. Go to the coast and stop by the Monterey Bay Aquarium Research Institute and see the Vampyroteuthis.

Oh, wait, that's the fake inflatable one. I don't think you'll get to dive down into the deep dark and see a real one. You might not want to.

pharyngula Fri, 07/28/2017 - 11:34

Friday Cephalopod: It's a whole weekend of developmental biology

pharyngula — Fri, 14 Jul 2017 09:16:59 +0000

Friday Cephalopod: It's a whole weekend of developmental biology

thenode

pharyngula Fri, 07/14/2017 - 05:16