How did some early Paleozoic animals expand to distant continents so fast?

[Hapchazzard]

I've noticed that a lot of clades that first appear in the early Paleozoic seem to immediately be present across the globe, even though the continents at the time were mostly disconnected and separated by oceans. For example, (calcified) trilobites suddenly appear in Cambrian Stage 3, but are already present in Laurentia, Siberia and parts of Gondwana, despite the vast distance and oceanic separation of the landmasses. Similarly, Rugose corals appear in the late Middle Ordovician, but already seem to present across the equatorial regions of the globe.

 

How did these benthic/sessile clades(so I'm not referring to pelagic trilobites) manage to spread geographically wide so fast? Is there any way we could know what landmass was the actual "birthplace" of some of them?

[Kane]

An interesting question. Have you read "On Some Causes Which May Have Influenced the Spread of the Cambrian Faunas" by George Frederic Matthew? It's fairly dated, but perhaps a good start. 

 

Matthew, G.F. (1891). "On Some Causes Which May Have Influenced the Spread of the Cambrian Faunas." Canadian Record of Science VOL.IV, January. LINK

 

[Hapchazzard]

27 minutes ago, Kane said:

An interesting question. Have you read "On Some Causes Which May Have Influenced the Spread of the Cambrian Faunas" by George Frederic Matthew? It's fairly dated, but perhaps a good start. 

 

Matthew, G.F. (1891). "On Some Causes Which May Have Influenced the Spread of the Cambrian Faunas." Canadian Record of Science VOL.IV, January. LINK

 

I did not, and I indeed might give some of the interesting-sounding chapters a quick read if I can find a free PDF version online. However, I'm not sure if the fact that the continents had a different configuration back in the Cambrian was even known in the 1890s, and without that knowledge I doubt that the main reasons and methods of environmental range expansion could be accurately known. 

[Kane]

Agreed. It might take some far-out inferences drawn from that text, coupled with an understanding of plate tectonics. Certainly would be, in Sherlock Holmes' terms, a "three pipe problem"!

 

I think that link should give the full access (it's only about 15 or so pages, digitized). I'll search my institution's collection and see if I can find something much more recent. My preliminary search generally yields up far more specific stratigraphic analyses rather than faunal spread globally. I hope to find something in the next few days.

[Hapchazzard]

5 minutes ago, Kane said:

Agreed. It might take some far-out inferences drawn from that text, coupled with an understanding of plate tectonics. Certainly would be, in Sherlock Holmes' terms, a "three pipe problem"!

 

I think that link should give the full access (it's only about 15 or so pages, digitized). I'll search my institution's collection and see if I can find something much more recent. My preliminary search generally yields up far more specific stratigraphic analyses rather than faunal spread globally. I hope to find something in the next few days.

Hmm, for some reason Google Books isn't actually displaying any pages for me. Maybe I don't have access permissions for it?

 

Anyway, if you find any interesting works/articles related to the topic, please do post them here if you can  . I'm highly interested in learning more about this topic.

[Kane]

Let me resolve that. I'll PM you a PDF.

[piranha]

This paper has figures that show the landmass progression of the early Cambrian to the Cambrian-Ordovician boundary.

 

Torsvik, T.H., & Cocks, L.R.M. (2013)

New global palaeogeographical reconstructions for the Early Palaeozoic and their generation.

Geological Society of London Memoirs, 38:5-24

 

It is part of this larger monograph with extensive info:

 

Harper, D.A.T., & Servais, T. (eds.)
Early Palaeozoic Biogeography and Palaeogeography.

Geological Society of London Memoirs, 38:1-490

 

Please send me a PM with your email address and I'll be happy to send it.

 

 

[EMP]

5 hours ago, Hapchazzard said:

How did these benthic/sessile clades(so I'm not referring to pelagic trilobites) manage to spread geographically wide so fast? Is there any way we could know what landmass was the actual "birthplace" of some of them

 

Well...we don't have a solid idea quite yet.

 

However, it's important to remember that when dealing with geologic time, even with something as specific as Zone 3 of the Cambrian, the epoch spans a time interval of a few million years, which is certainly a lot of time for larval trilobites or other creatures to spread across world oceans.

[Hapchazzard]

50 minutes ago, EMP said:

 

Well...we don't have a solid idea quite yet.

 

However, it's important to remember that when dealing with geologic time, even with something as specific as Zone 3 of the Cambrian, the epoch spans a time interval of a few million years, which is certainly a lot of time for larval trilobites or other creatures to spread across world oceans.

 

 

It isn't the time that's the problem, it's the geographic separation. In most maps of the early Paleozoic, Gondwana, Laurentia, Siberia and Baltica are represented as independent, ocean-separated continents, but despite that these benthic/sessile clades have somehow managed to rapidly spread across the globe. Planktonic larvae were also my first thought, but didn't trilobite planktonic larvae first appear in the order Asaphida, which evolved well after the original Cambrian diaspora? 

 

Anyways, I've found a work that's concerned with this specifically: 

 

Quote

 

Bruce S. Lieberman (2002): "Phylogenetic analysis of some basal early Cambrian trilobites, the biogeographic origins of the Eutrilobita, and the timing of the Cambrian radiation", Journal of Paleontology(IV edition)

 

 

The article claims that the trilobites originated in Siberia, and spread worldwide during the existence of Pannotia, becoming quite diverse during that time. When Pannotia broke up, the Olenellid and Redlichiina zones developed due to the separation of Laurentia-Siberia and Gondwana. 

 

There's only one thing that's really bugging me with this explanation: wouldn't this imply that calcified shells evolved separately in the two zones, but somehow did so in the practically exact same geologic time? Isn't this exceedingly unlikely?

[doushantuo]

There are,of course,several paleocontinental reconstructions,as i've said repeatedly on this forum.

Also,there is(probably) a host of dispersal models.

And the discussion on lecithotrophic and/or planktotrophic larvae is never-ending.

I can think of several good articles on paleogeography btw,and there's the eponymous magazine published by you-know-who.....

The geological survey of Austria has an excellent special issue(1999) of their Abhandlungen devoted to Paleozoic paleogeography.

Which is freely downloadable,i think.

Btw,a lot of people forget that most Paleozoic sutures were subducted in the Mesozoic .Global mapscale reconstructions are not cut and dried .

R. Damian Nance and Murphy have published a LOT on paleogeography,vide infra.

 

 

a fairly new article on methodology:

vavr

 

shorty on p-geography

Leesetal

 

[EMP]

10 hours ago, Hapchazzard said:

It isn't the time that's the problem, it's the geographic separation. In most maps of the early Paleozoic, Gondwana, Laurentia, Siberia and Baltica are represented as independent, ocean-separated continents, but despite that these benthic/sessile clades have somehow managed to rapidly spread across the globe. Planktonic larvae were also my first thought, but didn't trilobite planktonic larvae first appear in the order Asaphida, which evolved well after the original Cambrian diaspora? 

 

Anyways, I've found a work that's concerned with this specifically: 

 

10 hours ago, Hapchazzard said:

 

12 hours ago, EMP said:

 

Well...we don't have a solid idea quite yet.

 

However, it's important to remember that when dealing with geologic time, even with something as specific as Zone 3 of the Cambrian, the epoch spans a time interval of a few million years, which is certainly a lot of time for larval trilobites or other creatures to spread across world oceans.

 

 

It isn't the time that's the problem, it's the geographic separation. In most maps of the early Paleozoic, Gondwana, Laurentia, Siberia and Baltica are represented as independent, ocean-separated continents, but despite that these benthic/sessile clades have somehow managed to rapidly spread across the globe. Planktonic larvae were also my first thought, but didn't trilobite planktonic larvae first appear in the order Asaphida, which evolved well after the original Cambrian diaspora? 

 

Anyways, I've found a work that's concerned with this specifically: 

 

Quote

 

Bruce S. Lieberman (2002): "Phylogenetic analysis of some basal early Cambrian trilobites, the biogeographic origins of the Eutrilobita, and the timing of the Cambrian radiation", Journal of Paleontology(IV edition)

 

 

 

 

 

The article claims that the trilobites originated in Siberia, and spread worldwide during the existence of Pannotia, becoming quite diverse during that time. When Pannotia broke up, the Olenellid and Redlichiina zones developed due to the separation of Laurentia-Siberia and Gondwana. 

 

There's only one thing that's really bugging me with this explanation: wouldn't this imply that calcified shells evolved separately in the two zones, but somehow did so in the practically exact same geologic time? Isn't this exceedingly unlikely

 

 

Yes and no. If the common ancestor had a calcified shell there's no real problem, and it's important to remember that trilobites weren't apparent the moment the Cambrian started but rather a few million years afterwards. There were calcified shelled organisms before the trilobites. 

 

On the flip side let's say that the common ancestor didn't have one. Having a shell is a huge evolutionary advantage for an animal, especially at a time when most other (but not all) animals weren't shelled which would've made a potential predator skip over you and go to the next guy. With such a huge advantage it was really only a matter of time for the trilobites and most other animals to develop a shell to protect themselves, since the similar environments of the early seas would have dictated as such. 

 

The only area I really can't explain are the eyes. Those are just too complex to me to just "appear" in the fossil record, but from what I've gathered from elsewhere is that the process of evolving them was going on before the first trilobites, and that by the time the trilobites were around there was enough pressure to warrant eyes. Now how trilobite eyes were before others I don't know. Maybe it's a similar case with shells?

[doushantuo]

brachiopdexample,quantitativemethods

[doushantuo]

acritarchexample

[doushantuo]

Ediacaran,goodpiece

[doushantuo]

trilo

[doushantuo]

Interesting!!!

This is in line with the work of Bischoff and Doglioni...

Deep mantle convection as the source/cause of two geodynamic longlived supercells

[doushantuo]

 

Youngpisc Palwod 2010.pdf

Gavin Young,long time student of paleozoic fish and their dispersal patterns,with a crash course on Hennigian systematics and vicariance biogeography

[Hapchazzard]

15 hours ago, doushantuo said:

There are,of course,several paleocontinental reconstructions,as i've said repeatedly on this forum.

Also,there are(probably) a host of dispersal models.

And the discussion on lecithotrophic and/or planktotrophic larvae is never-ending.

I can think of several good articles on paleogeography btw,and there's the eponymous magazine published by you-know-who.....

The geological survey of Austria has an excellent special issue(1999) of their Abhandlungen devoted to Paleozoic paleogeography.

Which is freely downloadable,i think.

Btw,a lot of people forget that most Paleozoic sutures were subducted in the Mesozoic .Global mapscale reconstructions are not cut and dried .

R. Damian Nance and Murphy have published a LOT on paleogeography,vide infra.

 

 

a fairly new article on methodology:

vavr

 

shorty on p-geography

Leesetal

 

 

Thank you for all the articles you've linked, they're very informative!

 

7 hours ago, EMP said:

 

 

Yes and no. If the common ancestor had a calcified shell there's no real problem, and it's important to remember that trilobites weren't apparent the moment the Cambrian started but rather a few million years afterwards. There were calcified shelled organisms before the trilobites. 

 

On the flip side let's say that the common ancestor didn't have one. Having a shell is a huge evolutionary advantage for an animal, especially at a time when most other (but not all) animals weren't shelled which would've made a potential predator skip over you and go to the next guy. With such a huge advantage it was really only a matter of time for the trilobites and most other animals to develop a shell to protect themselves, since the similar environments of the early seas would have dictated as such. 

 

The only area I really can't explain are the eyes. Those are just too complex to me to just "appear" in the fossil record, but from what I've gathered from elsewhere is that the process of evolving them was going on before the first trilobites, and that by the time the trilobites were around there was enough pressure to warrant eyes. Now how trilobite eyes were before others I don't know. Maybe it's a similar case with shells?

 

If the common ancestor had a calcified shell, why isn't it (more commonly) preserved in pre-Stage 3 strata?

 

As for the second point, I understand that a calcified shell was a massive advantage, but what are the chances of it evolving in two distinct, semi-isolated populations(the Olenellidae and Redlichiina zones) in virtually the exact same geologic time? I may be overestimating the unlikeliness of it happening, but it doesn't seem like something that would just happen coincidentally(of course, I'm not expert and I could be wrong).

[piranha]

Here is Fortey & Owens on the subject:

 

Fortey, R.A., & Owens, R.M. 

Evolutionary History.

In: Kaesler, R.L., ed. (1997)
Treatise on Invertebrate Paleontology, Part O, Arthropoda 1, Trilobita, revised. 
Geological Society of America - University of Kansas Press, 530 pp.

 

DISTRIBUTION OF ANCIENT CONTINENTS AND TRILOBITE EVOLUTION

That some kinds of trilobites were characteristic of extensive paleogeographic areas has been recognized for a long time. The application of plate tectonics to the Paleozoic to produce more reliable paleogeographic maps has made new sense of such provincial distributions, especially when they are taken in conjunction with biofacies patterns within a single paleocontinent (for example, COCKS & FORTEY, 1988, referring to Gondwana). Indeed, trilobite distributions themselves have played a part in deducing the distributions of paleocontinents, especially in the early Paleozoic (WHITTINGTON & HUGHES, 1972; COCKS & FORTEY, 1982). Because the inshore biofacies are more likely to be confined to a single paleocontinent, the distribution of such biofacies is the best guide to former distribution of continents, and evolution inshore is most likely to have proceeded as an endemic phenomenon. Some degree of endemism characterizes the greater part of trilobite history, because the climatic gradient, combined with the effects of separation of continental plates, produced endemic faunas. Hence the evolution of trilobites may have been driven as much by extrinsic, paleogeographic factors as by intrinsic, morphological change. No doubt this accounts, in part, for the repeated appearance of morphotypes, as described above.

 

Geographic separation of trilobite faunas is apparent from the Lower Cambrian (Atdabanian) onwards (RICHTER & RICHTER, 1941b; COWIE, 1971). The differentiation into major realms characterized by Olenellina (especially in Laurentia) and Redlichiina (especially in China and Australia) must, therefore, have happened in pre-Atdabanian times, but this phase of differentiation and vicariance has left no record. Hardly any genera are common to both regions, so that geographic differentiation was implicated early in the diversification of faunas (Fig. 208). There are characteristic Eodiscina and Redlichiina in China and distinctive Olenellina in Laurentia, and these are assumed to be the product of in situ evolution in those areas. Mixed faunas occur in Morocco and Siberia, but there are also endemics in these localities as in Scandinavia, which may indicate that there were already in the Early Cambrian still further biogeographic subdivisions. These early faunas were almost entirely inhabitants of shelves.

 

[goatinformationist]

This thread warms my librarian heart to no end.  Thanks for the research and references guys.