Octopods Historical Origin in Question

March 5, 2011
Guardian.co.uk

A fossil octopus found in Lebanon has dramatically changed zoologists' thinking on these creatures' historic origin.

An ultraviolet picture of the octopus fossil found in Lebanon, which is more than 95m years old. Photograph: Dirk Fuchs/Free University of Berlin

Keuppia levante is one of several newly discovered fossil octopus species found in Lebanon that challenge previous assumptions about the origin and age of the Octopoda. Along with Keuppia hyperbolaris and Styletoctopus annae, this species is now the earliest unequivocal fossil for the group.

Truly remarkable anatomical details were observable due to the fine-grained Cenomanian limestones in which these species were entombed 180-95 million years ago. Octopods were previously thought to have arisen in mid-Cretaceous times. Thanks to characters observed in these newly discovered species, scientists now think octopods appeared significantly earlier, possibly even in Jurassic times.

Quentin Wheeler is director of the International Institute for Species Exploration, Arizona State University

Primitive Octopus Fossil: Pohlsepia Mazonensis

From: Tonmo.com
Written by: Phil Eyden, November 2004

Pohlsepia mazonensis was named after the person who discovered it, James Pohl, and the location, Mazon Creek. It is the earliest octopod that has been described to date and is approximately 296 million years old. Up until the recent discovery and publication of Pohlsepia in 2000 it was thought that the octopus lineage stemmed from the vampyromorphs sometime in the mid Jurassic, so it is obvious how important this discovery was of a soft-bodied octopod from the Upper Carboniferous (Pennsylvannian) as it pushed the origin of the octopus group back at least 140 million years further. It is important to remember that Pohlsepia clearly had its own ancestors and even at this early date had clearly defined cirrate-octopus features. The true origin of the octopods must have happened a few million years before even this remarkable fossil.

The fossil hails from the Upper Carboniferous deposits at Mazon Creek in Illinois, a source of extensive coal deposits. Many other cephalopods have been found in these deposits including nautiloids and the shelled torpedo-shaped ten-armed coleoid known as Jeletzkya. Specifically Pohlsepia comes from the Francis Creek Shale Member, this site of exceptional preservation consisted of rapid deposition of silt and sediments believed to have been at the mouth of a river delta where it met the sea. It is believed that storm surges following heavy rains swept masses of sediment down the river and out to sea burying coastal and marine animals and vegetation extremely rapidly. Concretions of ironstone then formed around the dead animals very quickly. Pohlsepia originates from the 'Essex' marine deposits and is preserved as a carbon film resembling a compressed stain inside one such nodule; this is typical for most fossils from Mazon Creek.


Just one example of Pohlsepia is known; as it is in a primitive condition the octopod actually has ten arms, two of these were modified but the other eight were approximately of the same length. The animal is small and is estimated to have had a Mantle Length of just 25mm long by 35mm wide. The animal lacks an internal shell much as with modern cirrate octopuses. The animal is sack shaped, has no clearly defined head and has very short arms. It also had two fins on its mantle, which are longer than they are wide, much like modern cirrate octopuses. The fossil has been preserved in a ventral aspect, eyes, a funnel, mandibles and a radula are identifiable and there is an indistinct feature that may represent an ink sac (extant cirrate octopods do not have these). No arm hooks or suckers are present. Peter Doyle and Joanne Kluessendorf published the fossil in 2000 and they have concluded that Pohlsepia should be assigned to the order Cirroctopoda.

Pohlsepia is housed at the Field Museum of Natural History, Chicago, Illinois.

Rare Octopus Fossil from Lebanon

The following information and pictures are from FossilMuseum.net.


Paleoctopus newboldi

Phylum Mollusca, Class Cephalopoda, Order Octopoda

Geologic Time: Middle Cretaceous, Cenomanian Stage (~95 million years ago)

Size: 85 mm long and 27 mm across tentacles

Fossil Site: Lebanese Lagerstatt, Haqel, Lebanon

Description: Here is a most unusual fossil from the Cretaceous of Lebanon; a very detailed octopus. Given the fact that there are no hard parts to preserve to speak of, the detail here is amazing, and testiment to the exceptional preservation often found in the Lebanese Lagerstatt. The last photo has been enhanced to bring out some features which are somewhat faint. The darkest area is actually preserved ink which the octopus would have used as a smokescreen to protect it from predators.

Octopus Fossils - They're More Rare Than You Think!

From: Tonmo.com, November 2004
Written by: Phil Eyden

Fossils of octopuses are by far the most enigmatic and mysterious of all the ancient groups of cephalopods. Due to their delicate structure fossils of these animals are exceptionally rare, as the soft-bodied nature of the animal does not lend itself to fossilisation. They are so rare that there is just one known from Illinois (296million years old), one from France (164m) and just a handful from Lebanon (89-71m). Very little is known about their history, how they evolved and developed, or their lifestyle. Following is a brief look at some of the theories surrounding them, the three octopuses themselves and the sites they were found in. It should be remembered that these three forms almost certainly do not represent a single line of descent.

Cretaceous Octopus With Ink And Suckers -- The World's Least Likely Fossils?

From: Science Daily, March 18, 2009

New finds of 95 million year old fossils reveal much earlier origins of modern octopuses. These are among the rarest and unlikeliest of fossils. The chances of an octopus corpse surviving long enough to be fossilized are so small that prior to this discovery only a single fossil species was known, and from fewer specimens than octopuses have legs.

Even if you have never encountered an octopus in the flesh, the eight arms, suckers, and sack-like body are almost as familiar a body-plan as the four legs, tail and head of cats and dogs. Unlike our vertebrate cousins, however, octopuses don't have a well-developed skeleton. And while this famously allows them to squeeze into spaces that a more robust animal could not, it does create problems for scientists interested in evolutionary history. When did octopuses acquire their characteristic body-plan, for example? Nobody really knows, because fossil octopuses are rarer than, well, pretty much any very rare thing you care to mention.

The body of an octopus is composed almost entirely of muscle and skin, and when an octopus dies, it quickly decays and liquefies into a slimy blob. After just a few days there will be nothing left at all. And that assumes that the fresh carcass is not consumed almost immediately by hungry scavengers. The result is that preservation of an octopus as a fossil is about as unlikely as finding a fossil sneeze, and none of the 200-300 species of octopus known today has ever been found in fossilized form. Until now, that is.

Palaeontologists have just identified three new species of fossil octopus discovered in Cretaceous rocks in Lebanon. The five specimens, described in the latest issue of the journal Palaeontology, are 95 million years old but, astonishingly, preserve the octopuses' eight arms with traces of muscles and those characteristic rows of suckers. Even traces of the ink and internal gills are present in some specimens. '

"These are sensational fossils, extraordinarily well preserved," says Dirk Fuchs of the Freie University Berlin, lead author of the report. But what surprised the scientists most was how similar the specimens are to modern octopus: "these things are 95 million years old, yet one of the fossils is almost indistinguishable from living species." This provides important evolutionary information. "The more primitive relatives of octopuses had fleshy fins along their bodies. The new fossils are so well preserved that they show, like living octopus, that they didn't have these structures." This pushes back the origins of modern octopus by tens of millions of years, and while this is scientifically significant, perhaps the most remarkable thing about these fossils is that they exist at all.