Talk:Trilobite/Archive 1

Biramous

With respect to the limbs, is biramous the right word to use? I know it has two branches, but they are not homologous at all to those of crustacean limbs.

AFAIK. The (1959)Treatise devotes a couple of pages to 'Biramous Appendages' and I've seen the term in a fair number of other places.

Sam Gon site

Are we allowed to reference other sites? Probably we should have a link to Sam Gon's trilobite page? http://www.aloha.net/~smgon/

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Yes we are, just as we can reference books. I'll add that.

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N.B. I followed the link to "Trilobite Orders" and noticed a note saying that the site will be moving soon to a new domain. So I thought I'd record some notes so it can be found again, next time someone looks and finds the link broken:

The top of the page reads

A Guide to the Orders of Trilobites
A site devoted to understanding trilobites
created and maintained by Sam Gon III

so try searching for that. Also contains "Trilobite of the Month".

Added text from an article I originally wrote in 1998 and published on the Web.

Dlloyd 21:33, 27 Jul 2004 (UTC)

Portions of this text are :

"Copyright © 1995-1997 The Fossil Company Ltd. © 1997-1999 The British Fossil Company Inc. and licensed by the owner under the terms of the Wikipedia copyright." Please contact me if you need further clarification on this.

Dlloyd 00:50, 30 Jul 2004 (UTC)

Should the copyright notice be on the thumbnails on this page, or only on the separate image description pages? AnonMoos 13:10, 2 November 2005 (UTC)

Trilobite Eyes

Trilobites had unique eyes, which were made of calcite (calcium carbonate, CaCO3).

How would anyone ever know what trilobite eyes were made of? I thought all we know about trilobites comes from fossils that have completely replaced the original substances of the eyes (whatever it might be) with rock. --DavidCary 01:15, 6 Nov 2004 (UTC)

I'll try to look into this and see if I can answer your question. --DanielCD 21:38, 8 Nov 2004 (UTC)

The answer is, I believe, that calcite is a fairly stable material, and so under the conditions that many trilobites were preserved, there would have been no replacement of the calcite by other minerals. The optical properties of calcite in the eye is so well preserved that you can "see" through the lenses and test the visual acuity of the original creatures. Hope this helps. --DanielCD 21:48, 9 Nov 2004 (UTC)

Trilobites' exoskeletons were preserved after death, in the fossilization processes. During this point, material was replaced with aVAILABLE PRESERVATION MATERIALS, OFTEN SILICA OR CALCITE. Some can be found using quartzite as a common material as well. In truth, we don't know what the eyes were made of, just that the material was often replaced. Some speculation has been put forward that it was calcite, but this is as of yet unproved fact (unless one were to count Niobella, that is).--??????? ??:??, ? ??? 200? (UTC)

No, DanielCD has it right -- trilobite calcite was low in magnesium and therefore highly preservable over hundreds of millions of years. The myth that all fossils are are mineral-replacements of ancient body parts is just that: a myth. Otherwise, there would be no way to do paleotemperature studies using fossil skeletal material. And even when conditions are ripe for mineral replacement of the original skeleton, quartzite is never the replacive mineral. In fact, it's not a mineral at all. Quartz, on the other hand, is a mineral, but never the replacive mineral either.--Pefty 16:33, 29 Sep 2006 (UTC)

-- Praetorbrutus

praetorbrutus@yahoo.com or,if you're looking at Trilo-Eye, catothecensor2005@yahoo.com

"Native Americans"

"The Native Americans had a name for trilobite which means "little water bug in the rocks"—a name which demonstrates extraordinary zoological acuity." This is like saying "The Asians had a name for..." --it's meaningless. Doubtless a Western North American tribe is meant. The "zoological acuity" would depend on the phrase being independent of a paleontologist saying, "and what would you call these?" Not to denigrate the zoological and botanical acuity of any of the "First Peoples." --Wetman 17:18, 11 Nov 2004 (UTC)

Well, fix it then. --DanielCD 21:43, 11 Nov 2004 (UTC)

And if you asked the paleontologist "and what would you call these?" he would probably remember that the Native Europeans had a name for trilobite which means "little thing with three lobes" - a name which demonstrates somewhat less zoological acuity - and he would use that. PAR 17:37, 2 November 2005 (UTC)

True, I mean all paleontological names are just simple discriptions in a dead language, cephalopod for instance just means "head foot" and is a simple discription of the vast majority of cephalopods. arthropod if i remember means "jointed foot" so trilobite fossils translated into basic english from the latin basicly means "three parted jointed foot animal in a rock" people need to stop with the superiority complex, esspecialy when the native americans at least recognized that it was a bug that lived in water, as opposed to say the greeks who worshipped fossils like mammoth skulls as cyclops, and said their bones belonged to humanoid giants. --THEBURK —The preceding unsigned comment was added by 64.28.253.222 (talk) 15:45, 22 March 2007 (UTC).

Not to denigrate the zoological and botanical acuity of any of the "First Peoples" of Europe. PAR 20:18, 2 November 2005 (UTC)

Trilobite Pictures

I was reading the article for the word "Fossil" and noticed that there is a very nice picture of a fossilized trilobite, complete with its eyestalks still attached. I think that this image should replace one of the ones on the page for trilobites. What do you all think?

Here is the picture I am talking about: http://en.wikipedia.org/wiki/Image:Trilobite2.jpg

Trilobite Pictures II

I added the pic mentioned above, but also changed the pic in the taxobox. The reason being that this one is really clear and shows the tripartate structure really well. Also, the pic of the trilobite in Death Valley got bumped due to space. I really didn't think it was that great anyway. If anyone wants it back, we can pull it from the history and restore it. --DanielCD 21:11, 19 Apr 2005 (UTC)

Telson

The term "telson" is used without being defined or linked. AnonMoos 13:10, 2 November 2005 (UTC)

External links

I restored 3 of the 5 external links - I think they are useful. The guide to orders of trilobites link is already a reference, and the trilobite cookies reference is not useful. PAR 20:27, 30 July 2006 (UTC)

Well, at least the cookies are gone. There are probably dozens of useful links regarding trilobites, but the addition of the five here smelled a lot like spam to me. —Preceding unsigned comment added by Likearock (talk • contribs)

merger

The page of cephalon was merged with trilobite. I put a redirect to trilobites. Someone add a description of the cephalon i did it because it was a trilobite organ and it was not good to have it seperateManav 95 21:07, 26 September 2006 (UTC)

Dimensions

I could not find any dimensions mentioned on the page. Average length, with and heights. —The preceding unsigned comment was added by Turbinator (talk • contribs) 19:25, 16 January 2007 (UTC).

There is this, under Physical description: Trilobites range in length from one millimeter to 72 cm (1/25 inch to 28 inches), with a typical size range of two to seven centimetres (1 to 3½ inches). The world's largest trilobite, Isotelus rex, was found in 1998 by Canadian scientists in Ordovician rocks on the shores of Hudson Bay. Does that help? Geologyguy 19:31, 16 January 2007 (UTC)

Yes, that is perfect. I can't believe that I missed it while reading. I can remember coming across some fossils on rocks similar to Trilobites but it was small - about one centimeter - so I was unsure of what it was. Kudos for the lightning fast reply. --Turbinator 19:40, 16 January 2007 (UTC)

Images

There are lots of nice images of fossils and some great diagrams of the exoskleton but there aren't any reconstructions of living trilobites (i.e. with legs) or showing them in their native environment. These would make a great addition if anyone can find or make any properly licensed images. Eluchil404 15:58, 15 February 2007 (UTC)

Want me to post some of my images in the article, then?--Mr Fink 16:29, 15 February 2007 (UTC)

I was thinking the same as Eluchil, so yes. —Pengo 04:08, 22 June 2007 (UTC)

Edit Notes

• not all trilobites had crescent-shaped eyes
• there were most likely many advanced eyes even in the early Cambrian SNP 01:15, 28 February 2007 (UTC)
• "true eyes" is ambiguous. Moreover, such advanced eyes as trilobites had means a lot of eye evolution had taken place. There were probably numerous animals with advanced sight, there eyes just were not so well-preserved as in trilobites, which were crystalline.
• there are many postulates about what sparked the cambian explosion, and "eyes" is not primary among them SNP 01:15, 28 February 2007 (UTC)
• The removed statement about trilobite eyes was problematic for two main reasons: 1) The notion of “true eye” is highly ambiguous, since it begs the question, what is an untrue eye?; and 2) the advanced eye of the trilobite, in fact, supports the hypothesis that true eyes abounded when trilobites appear in the fossil record. The cited book has interesting conjecture, but, presuming true eyes were somehow defined, stating that trilobites had the first ones, and that vision was born in a million years, are untestable hypotheses that also seem unlikely to be valid. As these would not survive peer review, I have removed these speculations. SNP 22:04, 24 March 2007 (UTC)
• I attempted to keep the phylogeny paragraph short; more extensive discussion should be added to the page for each order, and in some cases, certain suborders of trilobita. SNP 22:11, 24 March 2007 (UTC)
• The Nectaspida, because they lack a mineralized exoskeleton, are unlikely to be even a very close reletive to trilobites; they are often called soft-bodied trilobites, as a matter of trivia. Many are generally shped like agnostids. SNP 22:53, 24 March 2007 (UTC)

hypostome

This article should do more than simply mention the hypostome once, as it is crucial in modern discussions of trilobite phylogeny. The wikipedia entry on hypostome also needs wholesale work! Grahbudd 16:41, 14 July 2007 (UTC)

Extinction

Did the trilobites die out at the end of the Permian, or during the middle of the Permian?--Mr Fink 22:52, 15 August 2007 (UTC)

My recollection is that a couple of "dead clades walking" have been reported from post-Permian sediments. Although how robust the sediment dating is is anyone's guess... Verisimilus T 22:52, 1 September 2007 (UTC)

Gallery

This article was awash with images and it was becoming difficult to see the wood for the trees. 90% of them are too beautiful to remove so I've put them in a gallery. It's still a bit of a ramshackle layout though, someone with the patience may wish to neaten it a bit! Verisimilus T 22:52, 1 September 2007 (UTC)

Clean up

Can we get somethng going to be like the Ediacaran biota article. Enlil Ninlil 04:18, 9 September 2007 (UTC)

It does seem jumbled, life habits in the physical description etc. I'm contemplating a major re-organisation along these lines... Or am I splitting? Psuedomorph (talk) 19:45, 11 August 2008 (UTC)

Phylogeny / "the"

In the paragraph Phylogeny, there is repeated use of what seems to me to be less-than-perfect English, where there is no article in front of "order XYZ". Is this acceptable scientific style? --88.160.64.2 (talk) 14:05, 1 January 2008 (UTC)

Second-most famous fossil group

The second paragraph starts:

"Trilobites are very well-known, and possibly the second-most famous fossil group, after the dinosaurs."

I would have thought that the pterosaurs are more famous than the trilobites.--Codenamecuckoo (talk) 22:29, 1 February 2009 (UTC)

Shark teeth are the most commonly collected fossil in the world. Trilobites are very common, as far as fossil collecting goes. Dinosaur bones are few and far between, and cost big bucks, though that's not to say that there are some shark teeth that won't reach high prices. --Spotty11222 (talk) 01:44, 2 February 2009 (UTC)

Unless someone has a handy published consumer survey (or reference even) to settle the issue (DrKeirnan has a point) it should go. Perhaps someone should conduct a poll. Personally, I think trilobites are more interesting then pterosaurs or shark teeth... in the mean time...Psuedomorph (talk) 22:32, 9 March 2009 (UTC)

underside

I wonder there seem to be no trilobite fossils which are upside-down. Does this have a reason? Does a upside-down trilobite fossil exist? Apart from that - I'd like to know how the underside of a trilobite looks, and a picture would add a lot to the article.--TeakHoken89.14.7.45 (talk) 18:37, 22 March 2009 (UTC)

There is a picture that shows a view from underneath at the start of the exoskeleton section of the main article. Rocks split easier on the upper surface, and most trilobites if prepared properly would show the features underneath. Few people put in the extra effort to prepare trilobites with the underside fully exposed. Psuedomorph (talk) 13:15, 23 March 2009 (UTC)

Thanks, I must be blind. Is the picture really a view from underneath? The underline says 'ventral', but if I zoom the picture, it states 'dorsal'. It really seems to be the underside - there are no eyes. But I still have a question: What's the reason for the rock braking away easier on the top? Because the trilobite is less fissured on the top? Or is this the general case with all fossils? Is the reason the difference between ground and sediment?--TeakHoken193.187.211.118 (talk) 14:32, 2 April 2009 (UTC)

Always there are more questions... but that's part of the fun. ventral is just another way of saying belly or abdomen (view). Dorsal for back (Jaws (film) usually only showed the dorsal fin out of the water while "cruising"). I'll check the pic description but what you have is one example viewed from the side (lateral) and one from underneath (ventral) both in the same rock (interesting enough to post the picture I thought). I want to label the different features on the pic to clarify things, but haven't got round to it yet. Why more tops than bottoms? In trilobites, it's about the rock splitting off the relatively smooth outer shell rather than splitting into the knobbly, complex shape of the inner shell if you follow. This applies equally to all fossils. What sometimes happens is the rock splits right through the fossil and you get a cross section. What governs this is the type (and consequent mechanical properties) of the rock that contains the fossil: slate has a strong preferred splitting direction (cleavage) so you will often get reasonably clean split of rock from the fossil producing a positive (the fossil) and negative (impression of the fossil) although rarely get a completely clean split. Limestone, in contrast to slate, has no preferred splitting direction, so cross sections of trilobite are the norm. If I get organised I'll try and post some pics or someone else might have something relevant... If you have more questions best on my talk page before things go too far off topic... thanks Psuedomorph (talk) 13:41, 3 April 2009 (UTC)

PS you were quite right about the picture details, I've corrected them so that they are consistent. Psuedomorph (talk) 13:51, 3 April 2009 (UTC)

GA?

This is a very well-written, comprehensive article. I think that as soon as the article is more comepletely inlined, it can be nominated for GA. ResMar 19:28, 26 April 2009 (UTC)

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