Quote:palaeontologists from the South Australian Museum were last night en route to the remote site deep in the north of the state to further authenticate...
It's a big Paleontology emergency! How cool is that?
Other examples of Pikaia like creatures were found in China and in the Burgess shale. Given the continental layout at that time, I wonder how large a geographic spread that represented...
And these things apparently lived for at least 30M years... and they had to be eating something, so the seas must have been swarming with stuff. It must have been an amazing time, full of strange creatures all going about their lives on a planet as yet untouched by self awareness in any of its creatures.
http://www.scienceweb.org/can/news/nov96/n112696b.html
http://www.geo.ucalgary.ca/~macrae/Burgess_Shale
Holy Grail, eh? Hard to imagine that we'd actually find the first anything... Figures that an early one would look like a tadpole: embryology recapitulates phylogeny, or whatever it is those evolutionary bio people say.
Hmmm - lots of interesting fossils thereabouts - you see them on the side of the tracks in some places.
This one was used as a doorstop - or rather, the rock it was embedded in was - until the grazier had a chance to have a really good look at it, and then he thought he hadn't ever seen one like it before!
Rosborne. the pikaia fossils are , about 10 to 30 million years younger but the neat part is that Pikaia has, no doubt , a notochord and this new one seems to be a vertebrate, one step up. pikaia is probably the only evidence of the earliest chordates whereas this looks like (hoping its not a fake cause there is a lot of faking going on)its got a real backbone. All the rest of evolution then, is merely replaying the gene sequence over and over and adding newer options to the standard design. if this is a real find then the Cambrian explosion was truly that and fossils like pikaia are mere 'trials" since they have no follow-on species at younger rock series
I wish ican were here , Im afraid to go and even visit abuzz.
The locations of this fossil, so close to the Ediacara, so far from the burgess in Br Columbia, and the isua rocks of Greenland, give a newer synthesis of how many times continents were joined and split apart.
Does this mean Waltzing Matilda takes on a new, techtonic meaning?
Farmerman, What do you suppose would be the adaptive advantage of a backbone (other than metaphorical)?
The Flinders Range looks very interesting & beautiful:
I just looked up the ediacara dates from GSA , and theyve listed the dates of that assemblage as about 0.7 Billion years ago, barely the end of the Precambrian. conclusion, The ediacara are the earliest 'snackfoods' of the developing cambrian explosion fauna. So as Rosborne said, the flinders fossil finds are examples of development of more successful body styles and the ediacara are the experiments of evolution, and probably show that the oceans were teeming with available food groups for the developing notochords and vertebrates.
This may mean that critical percentages of Oxygen was available earlier than first thought.
earlyier assemblages, still precambrian, were loaded with massive reefs of stromatolites which were (are) large green sludge mats of algae like plants. These things appear about the same time in the precambrian when rocks show deposits of red sandstones, meaning rust, which means that excess oxygen was available for other things besides rusting rock iron.
Scuse me if Im slobbering, but to a geologist this has a lot of meaning in a number of areas including mine.
The trouble with the Journal of Paleontology, their ed board is composed of old fart academics who will drool all over the submitted paper so it wont get published for another year. Thats why NATURE is often the "national Enquirer" of science. At least it gets most of the facts out there near real time.
acquiunk-An advantage of a notochord is to allow the body to run neuro-transmission and circ fluids and at the same time allow for larger size of the animal because it promotes an internal skeletal structure. Insects and exoskeletal animals that are huge are all sea dwellers. so, a notochord or vertebra was probably an evolutionary throw of the dice which later was found to have an adaptive advantage only when the organisms became free living fish or later went topside.
Not being even remotely an expert in paleo, i will defer to other theories which can make more sense.
remember though, adaptive morphological advantages can be "dormant' until eons in the future.
Very interesting discussion! More please!~
rosborne-exactly. the science publishing racket is very slow in reporting. The peer review process, while important, spends more of its time with English grammar than the science.
drives me nutz all the time. Ive got a paper being reviewed for pub in a geo lournal, and its been in the hopper for almost a year.
Meanwhile, the credulous and the ill-educated get all the "science" they can read on the internet, and all without that messy peer-review process . . .
Quote:Ive got a paper being reviewed for pub in a geo lournal, and its been in the hopper for almost a year.
You'd've liked a guy I worked for. He got a lot of articles to review for biol. science journals (was a big shot in membrane something-or-other), and didn't bother one bit with those things. His reviews were generally very short: this works, this doesn't work, this is/isn't accurate and/or important enough to publish. Generally 80 words max, but those words were to... the... point.
farmerman wrote:Rosborne. the pikaia fossils are , about 10 to 30 million years younger but the neat part is that Pikaia has, no doubt , a notochord and this new one seems to be a vertebrate, one step up. pikaia is probably the only evidence of the earliest chordates whereas this looks like (hoping its not a fake cause there is a lot of faking going on)its got a real backbone. All the rest of evolution then, is merely replaying the gene sequence over and over and adding newer options to the standard design. if this is a real find then the Cambrian explosion was truly that and fossils like pikaia are mere 'trials" since they have no follow-on species at younger rock series
Another possibility is that the new fossil represented a line of vertebrates which went extinct, and Pikaia may still be our ancestor, by way of having developed a verterbae through convergent effects. This may be unlikely, but it's still a possibility.
It's also possible that the notocord type pikaia of the Burgess Shale were living fossils of a form of Pikaia which existed before the time of the new specimen. If this is so, then the Pikaia species (though not the particular ones in the Burgess shale) could still be the ancestors of the new creature found, even though the particular specimens were found in more recent rocks.
Right?
pikaia is an entire genera that , according to Gould, was just one of a mess of chordates that were having a tough time just existing in the mid Cambrian. He swz that the survival of Pikaia is a contingency of "just history" no higher answer was ever intended by him in his little book "A wonderful Life" which celebrates the stealthy survival mode of pikaia and the rise of Agnathans, true vertebrates , in the early Ordovician
in my field I use fossils as "worldwide indicators' of environments of deposition and mineralization rather than as examples of evolutions 'progress" Id be just as happy to see a very short lived, worldwide living fossil that only occured in , say, beach deposits like Scolithus, which is a nice indicator of petroleum.
Ive been followig this fossil and like p gracilens, and Walcotts "little worm' controversy, i see that today, theyre not quite certain that this may not just be a ciliated annelid. Oh well.
Set, yeh that nasty-ass peer review process takes all the fun out of presenting more nebraska Man and cardiff Giant fossils.
Two of my favorites, FM . . . i'm a sucker for the line of a good huckster . . .
Just another ciliated annelid?? Rats.
: http://www.publiclibraryofscience.org
