Is there a minimum size for fossil arthropods?

[BenBurch]

Do things as small as dust mites fossilize?

I wonder because we usually date the rise of complex multicellular life with the Ediacaran life, and those were all macroscopic critters (if they were critters) and I wonder if there were things like teeny-tiny trilobites long before any large enough to fossilize developed.

[drkitten]

Do things as small as dust mites fossilize?

I wonder because we usually date the rise of complex multicellular life with the Ediacaran life, and those were all macroscopic critters (if they were critters) and I wonder if there were things like teeny-tiny trilobites long before any large enough to fossilize developed.

My understanding is that microbes fossilize (http://www.ucmp.berkeley.edu/bacteria/bacteriafr.html).
I can't imagine trilobites being sufficiently smaller than the bacteria in the photographs above not to fossilize.

I think the simple problem is that there's not a lot of rocks that old, and that fossils that small are hard to find.

[RecoveringYuppy]

I came across the link below last weekend trying to figure out some reasonable approximations on how often things fossilize:

http://www.ars.usda.gov/is/kids/suburb/story2/mites.htm

[BenBurch]

I came across the link below last weekend trying to figure out some reasonable approximations on how often things fossilize:

http://www.ars.usda.gov/is/kids/suburb/story2/mites.htm

Well, that settles it! Thanks!

[Dr Adequate]

There are things like teensy-tinsy legless trilobites in the Precambrian (http://www.newscientist.com/article.ns?id=dn5070).

It seems that bilaterians started small.

[BenBurch]

There are things like teensy-tinsy legless trilobites in the Precambrian (http://www.newscientist.com/article.ns?id=dn5070).

It seems that bilaterians started small.

Tiny fossils less than a fifth of a millimetre across may reveal a critical step in the early evolution of animals. They show that internal complexity came before large size, suggesting paleontologists may have missed the earliest animals because they were microscopic.


That was just my thought in asking the question.

Thanks!
:thumbsup:

[cj.23]

I dropped a line to Professor Graham Budd, (see paper cited below) who responded thusly --

Well, there are two things here. i) The fossil is increasingly yielding microfossils of animals, a classic example being the Orsten fauna - see http://www.core-orsten-research.de/

So tiny arthropod fossils really do exist.

However, they are not known from the Precambrian, so although there was a lot of speculation about such things (it is not unreasonable) they have yet to turn up.

There are also some theoretical objections to tiny animals in the Cambrian, and perhaps the most comprehensive paper discussing this is G.E. Budd and S. Jensen, A critical reappraisal of the fossil record of the bilaterian phyla, Biol. Rev. 75 (2000), pp. 253–295

Hope this helps.

j x

[BenBurch]

Thanks!

[cj.23]

It's a pleasure Ben. Graham is heavily involved in this debate, and is I believe one of the worlds leading experts on fossil arthropods, that being his research area, so I thought I may as well ask for you. If you have more questions i'm sure he would help - he's a lovely chap.


cj x