Paleocene Proboscideans

[HadasL 0]

Hey,

I'm writing a paper on elephant evolution and am a bit murky on the Paleocene-Eocene specimens. I've read that after the PT-thermal maximum, Eocene mammals became the dwarfed counterparts of their Paleocene counterparts. But it seems to me like there's a trend of size increase, not decrease for the Proboscidea ancestors. Am I missing something?

Thanks!

[siteseer 1,724]

HadasL,

I am not a mammal researcher but I have a couple of friends who have been interested in the early probiscidean specimens that have been collected in Morocco. I happened to be standing nearby when they were talking about a few specimens that were available at a fossil show.

There was a time when a specimen was deemed Late Paleocene in age but later reconsidered as Early Eocene when associated shark/ray teeth were determined to have been reworked.(Gheerbrandt et al, 2002). However, along with that determination was the discovery of more apparent early probiscidean specimens reflecting a diversity of genera - a variety testifying that the lineage extended back into the Paleocene with less derived forms.

I don't know what you read in regard to dwarfism among early Eocene mammals but I agree with you that the trend seemed to be a size increase. Generally speaking, a large Paleocene mammal (e.g. Barylamda was around the size of a large Early Eocene mammal (Coryphodon, unitatheres) which is around the size of a modern dairy cow.

You might try contacting Emmanuel Gheerbrandt, a researcher who seems to be on top of early elephant research if not spearheading it.

For Gheerbrandt et al (2002):

http://app.pan.pl/archive/published/app47/app47-493.pdf

Hey,

I'm writing a paper on elephant evolution and am a bit murky on the Paleocene-Eocene specimens. I've read that after the PT-thermal maximum, Eocene mammals became the dwarfed counterparts of their Paleocene counterparts. But it seems to me like there's a trend of size increase, not decrease for the Proboscidea ancestors. Am I missing something?

Thanks!

[HadasL 0]

Thanks! I'll send him an email

[DD1991 216]

On 10/29/2013 at 9:43 PM, siteseer said:

HadasL,

I am not a mammal researcher but I have a couple of friends who have been interested in the early probiscidean specimens that have been collected in Morocco. I happened to be standing nearby when they were talking about a few specimens that were available at a fossil show.

There was a time when a specimen was deemed Late Paleocene in age but later reconsidered as Early Eocene when associated shark/ray teeth were determined to have been reworked.(Gheerbrandt et al, 2002). However, along with that determination was the discovery of more apparent early probiscidean specimens reflecting a diversity of genera - a variety testifying that the lineage extended back into the Paleocene with less derived forms.

I don't know what you read in regard to dwarfism among early Eocene mammals but I agree with you that the trend seemed to be a size increase. Generally speaking, a large Paleocene mammal (e.g. Barylamda was around the size of a large Early Eocene mammal (Coryphodon, unitatheres) which is around the size of a modern dairy cow.

You might try contacting Emmanuel Gheerbrandt, a researcher who seems to be on top of early elephant research if not spearheading it.

For Gheerbrandt et al (2002):

http://app.pan.pl/archive/published/app47/app47-493.pdf

A couple of early proboscideans have been found in the Paleocene of Morocco, Phosphatherium and Eritherium. References for these taxa are available at these links:

 

Emmanuel Gheerbrant (2009). Paleocene emergence of elephant relatives and the rapid radiation of African ungulates. Proceedings of the National Academy of Sciences of the United States of America 106 (26): 10717–10721. doi:10.1073/pnas.0900251106. PMC 2705600. PMID 19549873.

 

Gheerbrant, E.; Sudre, J.; Cappetta, H. (1996). A Palaeocene proboscidean from Morocco. Nature 383 (6595): 68–71. doi:10.1038/383068a0.

 

All I can say is the earliest proboscideans were small mammals that experienced a size increased as the Paleogene progressed.