Talk:Cephalaspis

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[edit] Disputed Data

What source says that Cephalaspis, a freshwater osteostracan of the Devonian, was preyed upon by Megalograptus, a marine Ordovician eurypterid, and Brontoscorpio, a marine Carboniferous scorpion? Isn't that analogous to saying that grizzly bears hunt Xiphactinus and arrowana?

Also, what source suggested that Cephalaspis was capable of generating electrical fields?--Mr Fink 03:15, 18 May 2006 (UTC)

It's WWM (Walking with Monsters). Some of the info is inccorrect, and I'll list the inaccuracies:

BBC needs to do more research. Making movies factually accurate makes them more intresting. They don't use "keywords" in evolution, like tetrapod and reptillomorph. One innacuracy I know from Walking with Beasts is that Phorusrhacos, a "terror bird", lived millions of years before Smilodon ever existed. GBA 23:15, 23 May 2006 (UTC)

There was nothing about Megalograptus, but there was a Pterygotus in the film. The Cephlaspis was swimming away from the Brontoscorpio (the Cephlaspis had a head start by sensing the electrical field of the Brontoscorpio). Then suddenly the Cephlaspis turns direction and a huge Pterygotus pops out of nowhere (expression, it actually popped out of the sand). Then it tears the Brontoscorpio apart. Cephlaspis was also featured swimming between freshwater and the ocean, kinda like salmon, 'cept they don't die after spawning.61.230.72.211 00:15, 21 June 2006 (UTC)

BBC gets more inaccuracies every sequel they make. Walking With Dinosaurs was quite welcomed, Walking With Beasts has one inaccuracy (Phorusrhacos living with Smilodon), but Walking With Monsters got a multitude of errors!61.230.72.211 00:17, 21 June 2006 (UTC)

Most of the speculation in WWM is not even plausible, like Cephalaspis having a thick skull to protect it's complex brain. Some animals that lived after Cephalaspis and are distant relatives of humans didn't have complex brains (Hynerpeton, Dimetrodon etc.). I never saw Cephalaspis even doing intelligent acts. I don't think Cephalaspis was even able to create electrical feilds to detect predators. Cephalaspis used it's thick skull for protection. "Thanks to these fish, we can think and solve problems today.", that phrase makes me laugh because it's very erroneous! It should be replaced with "Thanks to these fish, we have lampreys and hagfishes who clean up the seas." Giant Blue Anteater 00:36, 1 July 2006 (UTC)

How can you see Cephalaspis do intelligent acts!? 61.230.78.244 06:23, 4 July 2006 (UTC)

Cephalaspis did instinctive actions (spawning), but thats all. I doubt that Cephalaspis needed a complex brain. Giant Blue Anteater 06:39, 4 July 2006 (UTC)

Regarding the generation of Electrical fields, most of todays modern sdhark and some of the eels creat electrical fields to detect their prey. This is an adaptation that does not require intelligence to have or use. I would caution against making to many assumtions one way or another about an creatures appering in a television documentery because as everyone has pointed out the facts are always tweeked to make the show more exciting for the viewers. Kevmin 16:32, 4 July 2006 (UTC)

By the way, Tim Haines (hope you know who he is) has written an encyclopedia about most of the animals (not all) in the Walking With... Series ( including the specials). Look at this:

About Hynerpeton

  • "Primitive amphibian"
  • "Hynerpeton is a primitive amphibian..."
  • "Like modern amphibians..."
  • "Hynerpeton is just one of the several primitive amphibians..."
  • "These early amphibians are sometimes collectively called primitive 'tetrapods', whuch simply means 'four legs'."
  • "The study of primitive amphbians..."
  • "...these early amphibians..."
  • "...large amphibians..."

About Seymouria

  • "A land-living amphibian"
  • "Labyrinthodont amphibian"
  • "...but Seymouria was one amphibian..."
  • "All of this meant that Seymouria, unlike other amphibians..."
  • "...better than most amphibians."
  • "It was eventually deduced that its biology was more amphibian than reptilian."
  • "Seymouria is part of the seymouriamorpha subgroup of amphibians, but it is often described as being a 'reptilomorph'. This means that, like Proterogyrinus, it is part of the group of amphibians from which reptiles evolved."

About Cephalaspis

  • "...may have been the ancestor to jawed fish (such as Hyneria), and thus also the ancestor of all land vertebrates, including humans."

Now, I have no objection to BBC speculating Cephalaspis could generate electrical fields, 'cause paleontology is a lot about guesswork. Even the most "general facts", for example, Tyrannosaurus walked on two legs, could be wrong, however right that seems. It's simply the most possible guess. But making Cephalaspis the ancestor of all vertebrates is quite wrong, and is to be going too far! I"m a REALLY BIG fan of the Walking With... Series, but that doesn't mean I believe everything they say! 61.230.90.241 03:48, 8 July 2006 (UTC)

By the way, I've found an inaccuracy in Walking With Dinosaurs. Ornithocheirus was NOT the biggest pterosaur, Quetzalcoatlus was. Dora Nichov 03:51, 2 September 2006 (UTC)

Right, but that's not a really big inaccuracy, but saying Cephalaspis is the ancestor to gnathostomes is. What other source suggests this? Giant Blue Anteater 21:57, 21 September 2006 (UTC)
I know of no other sources that also suggest that Cephalaspis was the ancestor to the gnathostomes. Most experts lean toward the Thelodonts as the most likely gnathostome sister group.--Mr Fink 03:26, 22 September 2006 (UTC)
I googled "Thelodonts ancestor to gnathostomes" but there's nothing relevant to the search. Which source suggests thelodonts are the ancestor of gnathostomes? The first gnathostomes appeared in the latest Ordovician. Most thelodonts I know are from the Silurian to the Devonian (the period when the Canadian fork-tailed one appeared). Giant Blue Anteater 20:32, 25 September 2006 (UTC)
Did you try reading copies of the books "Rise of Fishes", "Fossil Fishes" or "Early Vertebrates"? The source that you found that said the very first gnathostomes being in the Late Ordovician is wrong: the first verifiable gnathostomes are the acanthodians, which first appeared during the Mid Silurian.--Mr Fink 06:38, 26 September 2006 (UTC)
I'll get those books. The Wikipedia article says that the first ever gnathostomes appeared in the late Ordovivian. Giant Blue Anteater 22:06, 26 September 2006 (UTC)
A brief discussion by Philippe Janvier is available at the Three of Life website: http://www.tolweb.org/Vertebrata/14829 Osteostracans are, according to their tree, closely related but not ancestral to the gnathostomes. Orcoteuthis (talk) 12:27, 25 February 2008 (UTC)


[edit] Intro

"Although it was heavily armored, this fish was an osteostracan cephalaspidomorph fish, and should not be confused with its jawed contemporaries, the placoderms." This is an odd thing to say - it makes it sound as if armour was anomalous for osteostracans, when in fact it's the norm. Armour was very common among Palaeozoic fishes of various groups, both gnathostomes and agnaths, and by no means restricted to placoderms. I'll take the liberty of changing it to something less misleading. Orcoteuthis (talk) 12:37, 25 February 2008 (UTC)