Trilobite size and locations?

[PaulK]

I have a few questions about trilobites.

 

1) Does anyone know the size of the largest trilobite ever found?

2) What is the average size of a trilobite in North America, specifically New York state?

3) What is the average size of a trilobite found in Morocco?

4) Why does it seem like trilobites are mostly found in New York state and Morocco? Do maps of what the Earth might of looked like during the Devonian period?

 

I had a bit of a disappointing first hunting trip for these little creatures in Tully, NY yesterday and any answers that will help me better understand them will be appreciated greatly.

[Kane]

1) Isotelus rex found in Manitoba by a team led by David Rudkin, measuring about 72 cm in length.

2) Hard to pinpoint as trilobites range in size, so it would be better to refine the question as to average size over all known species, or occurrences. Either would result in different answers.

3) Same as above. 

4) That may be a function of the availability heuristic whereby you may only hear more information about trilobites collected in these locations, but trilobites are found on virtually every continent, and there are numerous trilobite collecting localities worldwide. 

[Fossildude19]

Earth during the Devonian

[Kane]

And this may be helpful, too, in order to show how the number of genera decline precipitously after the Ordovician: http://trilobites.info/geotime.htm

[fifbrindacier]

On the quarry of Arouca, Portugal, the team of Juan Carlos Gutierrez Marco (Instituto de geologica econòmica of the University Complutense of Madrid) found Ogyginus forteyi and Hungioides bohemicus species, they estimated the size of the biggests at 90 cm.

[Kane]

11 minutes ago, fifbrindacier said:

oIn the quarry of Arouca, Portugal, the team of Juan Carlos Gutierrez Marco (Instituto de geologica econòmica of the University Complutense of Madrid) some trilobites measured 90 cm.

From what I've read thus far, none of them have been found complete and are extrapolations based on fragments. The Isotelus rex is the largest relatively complete example. I'll have to dig around to see if the Ogyginus forteyi found at Arouca tops that. 

 

Here's a nifty size chart of the giants from Sam Gon III's site:

 

[fifbrindacier]

7 minutes ago, Kane said:

From what I've read thus far, none of them have been found complete and are extrapolations based on fragments. The Isotelus rex is the largest relatively complete example. I'll have to dig around to see if the Ogyginus forteyi found at Arouca tops that. 

 

Here's a nifty size chart of the giants from Sam Gon III's site:

 

You're right, that's an estimation made partly with pygidiums found there. I was Editing my post when you answered.

 

In France there is a well known area"Montagne Noire" when you can find plenty of species from the Ordovician and the Cambrian. Their size go from millimeters to multipe centimeters.

[Kane]

Perhaps a reasonable average estimate of trilobite size for where the OP is collecting (Tully, NY) might be about 2-4 cm. Although trilobites in the Moscow are relatively plentiful, they are not the dominant fauna.

[ricardo]

6 hours ago, fifbrindacier said:

On the quarry of Arouca, Portugal, the team of Juan Carlos Gutierrez Marco (Instituto de geologica econòmica of the University Complutense of Madrid) found Ogyginus forteyi and Hungioides bohemicus species, they estimated the size of the biggests at 90 cm.

 

Paper   

 

The largest trilobite specimen ever recorded (Isotelus rex) has a reconstructed  exoskeletal  length  of  72  cm  (Rudkin  et  al.,  2003).  The  Arouca  lagerstätte has produced a 70-cm-long, almost complete fossil of Ogyginus forteyi (Fig. 2F); however, extrapolation from a 21-cm-long isolated pygidium of Hungioides bohemicus (Fig. 2B) suggests a total length of 90 cm.  

 

Regards

[PaulK]

10 hours ago, Kane said:

And this may be helpful, too, in order to show how the number of genera decline precipitously after the Ordovician: http://trilobites.info/geotime.htm

Thank you very much for that link! The website looks like it has a lot of useful information.

 

10 hours ago, Kane said:

Perhaps a reasonable average estimate of trilobite size for where the OP is collecting (Tully, NY) might be about 2-4 cm. Although trilobites in the Moscow are relatively plentiful, they are not the dominant fauna.

I was curious about trilobites in general. I wouldn't mind traveling to other places to look for them.

 

When I was 15 years-old I visited a cousin of mine who had a trilobite fossil that was about the size of a grown man's hand. I only saw that fossil once and it was 35 years ago, I don't know where my cousin acquired it from (obviously not around Tully, NY). With all of the much smaller trilobites that I have seen online, I was starting to think that the size of my cousin's fossil was just a figment of my imagination.

 

Thank you to everyone who replied to my questions. It's amazing to know that some trilobites grew to be over 2 feet long when most around my area are much less than 2 inches in length.

 

[piranha]

9 minutes ago, PaulK said:

...When I was 15 years-old I visited a cousin of mine who had a trilobite fossil that was about the size of a grown man's hand. I only saw that fossil once and it was 35 years ago, I don't know where my cousin acquired it from (obviously not around Tully, NY). With all of the much smaller trilobites that I have seen online, I was starting to think that the size of my cousin's fossil was just a figment of my imagination.

 

 

Dipleura dekayi would fit that large size from Tully, NY.