Talk:Ichthyostega

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This article was the subject of a Wiki Education Foundation-supported course assignment, between 7 September 2020 and 11 December 2020. Further details are available on the course page. Student editor(s): Gomezt2.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 00:14, 17 January 2022 (UTC)

Recent work (2005)
The illustration is definitely out of date. Jenny Clack (Cambridge) and Henning Blom (Uppsala) have done significant work on Ichthyostega over the past few years, substantially altering ideas about it. See Jenny's web site at http://www.theclacks.org.uk/jac.

The manus is still unknown, but most of Jarvik's work has been extensively revised. I'm brand new to Wikipedia so mostly don't know how to do things, for instance, updating the picture. Rob Clack 12:52, 30 January 2006 (UTC)

Redirect
Oops! In the edit summary field for the article I really meant 'avoid redirect', not disambig of course. Andrewa 18:07, 18 Mar 2004 (UTC)

Land or swamps?
This article appears to disagree with itself on whether the Ichthyostega walked on land or not. At the start of the article, it says that the Ichtyostega probably didnt 'walk' with its limbs at all, but the rest of the article acts as if it did. I suppose there is disagreement regarding this, but the article should probably mention that rather than just being confusing. Is there anyone who actually knows anything about Ichthyostega who could clear this up? Oscar Evans 22:12, 12 Feb 2005 (UTC)


 * I slightly remember a national geographic article (about a year (or 2?) ago) about Acanthostega and Ichthyostega that noted something like 'of course these animals didn't walk the land', they used their strong fins to move away plants in the shallow water'. I'll take a look at it. Phlebas 20:41, 16 Feb 2005 (UTC)

The illustration
I doubt the illustration used in this article is correct. It gives the impression that the animal had well developed feet adapted for actual walking. Since newer evidence tells that Ichthyostega never looked like that, the illustration is probably a little too old.

I have added a more accurate image today. But I did not replace the one in the taxobox, below is the image:



Ichthyostega would probably slide on wet surfaces (i.e. mud) rather than walk. The image correctly shows that Ichthyostega's hind limbs were poorly developed. Giant Blue Anteater 23:00, 14 June 2006 (UTC)

Edited a bit
"Amphibians gained a tremendous advantage by moving on land as they could avoid large predatory fish that ruled the rivers and lakes."

Most of the early tetrapods were large predators themselves, and Ichthyostega was not a true amphibian if I have understood it correctly. And there where other advantages by moving onto land than just avoiding predators, and just as important.

"The move also came with disadvantages such as the new requirement of a moist, gas-permeable skin in order to aid the inefficient lungs."

This only goes for modern amphibians. The first tetrapods had thick skin and their lungs where good enough to supply them with air.

Images Update
The old image in the template box was indeed outdated, based on a faulty sketch from the 60s. I re-drew it, based on |this reconstruction in 2005.

I also deleted Giant Blue Anteater's image, as it looked pretty unprofessional and cartoonish.

--Meneitherfabio 17:10, 29 September 2006 (UTC)

That picture (the redrawn one) is more accurate. But thats the way I draw, but tried to make as accurate as possible. Sorry. Giant Blue Anteater 01:23, 30 September 2006 (UTC)


 * Many thanks to both of you for improving on the accuracy of the illustration. As a professional involved in illustration, though not a professional illustrator, I'd point out that personal style is a matter of taste and very difficult to eliminate. The newer illustration is more in line with the "house style" of uncoloured line drawings used for most of these beasts, but the line weight of the outline appears too fine on my set up, and it would look more professional if thickened a bit. I'll incorporate the revised image into the fishapods illustration to the right, but having recently swapped over Eusthenopteron and Panderichthys on finding that the former was pelagic rather than air-breathing in the shallows as thought previously, I'd appreciate any comments on the sequence so that any necessary alterations can be made at the same time. ..dave souza, talk 08:43, 1 October 2006 (UTC)

New Image to Be Added
I am going to add a picture of what I presume a tadpole of Ichthyostega would look like. However, I am asking you guys wether I should add it. Giant Blue Anteater (talk) 01:50, 4 January 2008 (UTC)
 * What are you using as a reference? If there's no evidence of what a tadpole from an Ichthyostega would have looked like, and no published speculation, I'm not sure it's appropriate to simply make something up. Dinoguy2 (talk) 02:34, 4 January 2008 (UTC)
 * I primarily based it on salamander tadpoles, but also used lungfish fry as a template. Giant Blue Anteater (talk) 02:45, 5 January 2008 (UTC)
 * Ok, but what source says Ichthyostega tadpoles looked like that? Dinoguy2 (talk) 00:22, 6 January 2008 (UTC)
 * Not much is discussed about the larval forms of basal tetrapods. So, I can conclude that I made it up. Giant Blue Anteater (talk) 13:23, 6 January 2008 (UTC)
 * Ok, and that's fine--I've done images of creatures known from poor remains that are almost entirely educated speculation (like Unenlagia]. But it's not really appropriate for an encyclopedia article. Speculation about the appearance of an animal based on scrappy remains is one thing, but this is an animal (well, life stage) known from no remains at all! Dinoguy2 (talk) 16:59, 6 January 2008 (UTC)

Vandilism that I Can't Get Rid Of
Someone that knows how, get the "BITCH" taxon off the page. I can't get it to show up in any of the editors. -- User:76.6.217.213


 * The what? Evercat (talk) 00:15, 19 November 2011 (UTC)

Devonian origin of Fish, Bony Fish, Amphibians due to Jaws ?
The Devonian was the "Age of Fishes", due to their "quantum leap" in their evolution, of jaws. Jaws, enabling the mouth to be enlarged to eat bigger food items, made fish so successful, that they diversified worldwide. That geographic expansion & genetic diversification (including the archaic split between cartilaginous & bony fish) set the stage, for some small few (bony) fish to evolve into amphibians. Also, all early amphibians discussed in the article (Icthyostega, Acanthostega, Elginerpeton, Obruchevicthys) are known from fossils recovered from Greenland, Scotland, & Latvia. c.370Ma, those terranes were adjacent parts of the subsiding Caledonian mountains uplifted c.400Ma, on the northern Euramerica portion of Pangea; and all of those terranes were also adjacent to the then-rising  Variscan mountains to their immediate south:
 * http://s7.postimage.org/sldlakk0r/Amphibians.png

Somehow, the Caledonian mountains must have rapidly eroded, swiftly subsided, or world sea levels must have been higher, so as to make mountains into swamp shores, inhabitable by transitional pre-amphibians.66.235.38.214 (talk) 11:31, 19 October 2012 (UTC)
 * Carboniferous period coal deposits, deriving from swamp forests, reside in regions uplifted by mountain-building events c.400-300Ma, e.g. Caledonian & Variscan orogenies between Euramerica & Gondwana; and the Urals between Siberia & Euramerica. Ipso facto, mountainous regions may have formed low-lying swamp islands, suggesting that then-global sea levels were higher than present epoch, and that much of the interiors of continents were flooded over, by inland seaways:
 * http://www.ruf.rice.edu/~leeman/CarbCoal.gif
 * 66.235.38.214 (talk) 11:50, 19 October 2012 (UTC)
 * All of the earliest reptile fossils have been found in the same region, as the earliest amphibian fossils, e.g.
 * Westlothiana, from 350 million years ago, either an early amniote or a sister group to the amniotes
 * Casineria, from 340 million years ago, a basal amniote.
 * Hylonomus, from 312 million years ago, another early anapsid reptile
 * Paleothyris, from 312 million years ago, an early sauropsid
 * Petrolacosaurus, from 302 million years ago, the first diapsid reptile
 * Archaeothyris, from 306 million years ago, an early synapsid (mammal-like reptile)
 * Ipso facto, the first amphibians waddled ashore, onto northern Euramerica, about 375Ma; and there they evolved, in situ, into the first reptiles, by about 300Ma. At no time did they disperse widely, nor did they surmount then then-young-and-tall Variscan mountains to the south; they never ventured into Gondwana.  Amphibians & primitive reptiles were slow, cold-blooded, crawlers.  They could not fly.  And they were hemmed in by mountains to the south, ocean to the north, and swamps on all sides.  Only in the Permian period did reptiles begin to expand across Pangea.66.235.38.214 (talk) 12:07, 19 October 2012 (UTC)
 * Transitional reptilomorph Proterogyrinus lived 320Ma from Scotland to West Virginia. Full-fledged diapsid Petrolacosaurus lived 300Ma in Kansas.  Thus, a general Amphibian-cum-Reptilian expansion southwards, up the slopes of the Variscan mountains, between Euramerica (north) and Gondwana (south), can be construed:
 * http://s9.postimage.org/9az6hl7ov/Reptilians.png
 * 66.235.38.214 (talk) 12:30, 19 October 2012 (UTC)


 * Possibly so, but it's all "Original Research" (see WP:OR) unless you can find reliable sources for it. Chiswick Chap (talk) 21:18, 19 October 2012 (UTC)

Operculum
In the Description section it says: The posterior margin of the skull formed an operculum covering the gills. It's my understanding that the gill-covering bones disappeared in the Elpistostegalians (the most tetrapod-like of the tetrapodomorph fishes) some time after Panderichthys. These bones are missing in Elpistostege and Tiktaalik. They are not present in any early tetrapods. There is an explanation of this in the tetrapod article, in the Tetrapod section. However, there would have been a flap of "skin" called the operculum. Zyxwv99 (talk) 23:23, 30 July 2015 (UTC)