Octopus had Antarctic ancestors

Genetic analysis of octopodes indicates that they developed in the ocean around Antarctica. They spread out from that continent when an ice sheet covered it and created cold water currents in all directions to the north.

By Alister Doyle, Environment Correspondent

OSLO (Reuters) – Many octopuses evolved from a common ancestor that lived off Antarctica more than 30 million years ago, according to a “Census of Marine Life” that is seeking to map the oceans from microbes to whales.

The $650 million census is on track for completion in 2010, assessing about 230,000 known marine species, a statement said. It has identified 5,300 likely new species, of everything from fish or corals. So far, 110 have been confirmed as new.

Among the findings, genetic evidence showed that the tentacles of the octopus family pointed to an Antarctic ancestor for many deep sea species. A modern octopus called Adelieledone in Antarctica seemed the closest relative of the original.

Octopuses apparently spread around the world after Antarctica became covered with a continent-wide ice sheet more than 30 million years ago, a shift that helped create oxygen-rich ocean currents flowing north, a report said.

“Isolated in new habitat conditions, many different species evolved; some octopuses, for example, losing their defensive ink sacs — pointless at perpetually dark depths,” the census said.

Classification: Biota > Animalia (Kingdom) > Mollusca (Phylum) > Conchifera (Subphylum) > Cephalopoda (Class) > Coleoidea (Subclass) > Octopodiformes (Superorder) > Octopoda (Order) > Incirrata (Suborder) > Octopodoidea (Superfamily) > Octopodidae (Family) > Adelieledone Allcock et al., 20

Marine life: octopods and squids

It’s Cephalopod Appreciation Day!

Image from the U.S. Smithsonian National Museum of Natural History.


The LOLluscs are coming!


more funny pictures

Posted in humor. Tags: , , . 1 Comment »

Squid dissection recordings

colossal squid being caught

You can go to the Web site of the Te Papa Museum for recordings of their lectures and webcasts about the recently dissected squids. The colossal squid is Mesonychoteuthis hamiltoni and the giant squid is Architeuthis.

Lectures recordings

The audio recording of Science Express is available:

The other lectures have been filmed. The videos will be available later. Some copyright issues need to be sorted too, so this might take a little longer than expected.

Webcast retransmission

A retransmission of the last hours of the webcast are available here:

Deep Sea News: colossal squid vs. giant squid

colossal squid, top view, being held by five men

Craig at Deep Sea News talks about the two squid being dissected in New Zealand.:

To bring you up to speed, a crack team of teuthologists* dissected both Giant and Colossal Squids at the Te Papa Museum in New Zealand last week. This is where the confusion arises as a Giant Squid AND 2 Colossal Squid were dissected. One of these was the 495kg giant caught over a year ago by fisherman in the Antarctic (oh yeah…she’s a girl!). Seeing the media consistently confuse the two species greatly saddens me. But hey if the media always got it right there would be little need for DSN.

So for clarity the Giant Squid and the Colossal Squid are completely different. Below I provide a list that you can print out and keep in your wallet or purse along with your Seafood Watch card….

Read more.

The colossal squid is Mesonychoteuthis hamiltoni and the giant squid is Architeuthis.

Squid dissection online

logo of Te Papa museum in New ZealandI got a comment last week from “tepapamuseum”

If you are interested in giant and colossal squid, Te Papa will host and webcast the dissection of 4 giant and 2 colossal squid starting Sunday 27 April. More info can be found on our website: http://www.tepapa.govt.nz/squid/ and of course, on our blog.

For more information, visit the Museum of New Zealand Te Papa Tongarewa.

Colossal Squid being caught

You can see the Architeuthis here: “Rare giant squid washes up in Australia.”

Pharyngula’s Friday cephalopod: Octopus abaculus

As someone mentioned, today’s Friday Cephalopod has a rather fractal appearance.

Octopus abaculus (Norman, 1997)

Octopus abaculus is found only in the Phillippine Islands. It was formally described and named in 1997 by M.D. Norman and M.J. Sweeney 1:

The shallow-water octopuses of the Philippines are diagnosed on the basis of material collected in a series of expeditions by the Smithsonian Institution to the region between 1978 and 1990. Twenty species of shallow-water octopuses are recognised, 18 in the genus Octopus, and one species each in the genera Hapalochlaena and Cistopus. Three new species are described from Philippine waters: Octopus abaculus, O. nocturnus and O. pumilus. Octopuses reported in the earlier work of G. L. Voss on the cephalopod fauna of the Philippines are reviewed and identifications updated. A diagnostic key and illustrations are provided along with information on taxonomy, distribution, aspects of life history and importance in fisheries.

Here’s some information about benthic octopuses (PDF), written by M.D. Norman, from a FAO species identfication guide2.

Octopus abaculus, cephalopod, information

You can see its classification at Zipcode Zoo or the Animal Diversity Web.

  1. Norman, M.D. and M.J. Sweeney. The shallow-water octopuses (Cephalopoda: Octopodidae) of the Philippines, Invertebrate Taxonomy, 11 (1), 89-140. Full text doi:10.1071/IT95026.
  2. Carpenter, Kent E and Volker H. Niem. FAO Species Identification Guide for Fishery: The Living Marine Resources of the Western Central Pacific, Volume 2: Cephalopods, crustaceans, holothurians and sharks. ISSN 1020-6868.

Cephalopod development and evolution from Pharyngula

six-legged octopusA news story about an ordinary octopus that developed only six legs prompted PZ Myers at Pharyngula to refer readers back to one of his detailed articles, “Cephalopod development and evolution.”

One… question is how oysters could be related to squid; one’s a flat, sessile blob with a hard shell, and the other is a jet-propelled active predator with eyes and tentacles. Any family resemblance is almost completely lost in their long and divergent evolutionary history….

One way to puzzle out anatomical relationships and make phylogenetic inferences is to study the embryology of the animals. Early development is often fairly well conserved, and the various parts and organization are simpler; I would argue that what’s important in the evolution of complex organisms anyway is the process of multicellular assembly, and it’s the rules of construction that we have to determine to identify pathways of change. Now a recent paper by Shigeno et al. traces the development of Nautilus and works out how the body plan is established, and the evolutionary pattern becomes apparent.

He’s referring to “Shigeno S, Sasaki T, Moritaki T, Kasugai T, Vecchione M, Agata K. (2007) Evolution of the cephalopod head complex by assembly of multiple molluscan body parts: Evidence from Nautilus embryonic development. J Morphol. [Epub ahead of print].”

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