Humans, Chimps and now Mammoths?

The complicated search for well preserved DNA in fossils has recently advanced with the sequencing of 13 million base pairs of endogenous genetic material from a female mammoth jaw bone discovered on the Taimyr Peninsula of the Russian Federation. This is greater than the 27,000 base pairs recently sequenced from the extinct cave bear. Mammoths share 98.55% of the same genetic material with living elephants, which validates the 5 million year divergence time between the two species. Large scale sequencing of "fossil" DNA will bring about new perspectives of these interesting creatures, and may lead to the cloning of mammoths in the near future.


Poinar, Hendrik N., Schwarz, Carsten, Qi, Ji, Shapiro, Beth, MacPhee, Ross D. E., Buigues, Bernard, Tikhonov, Alexei, Huson, Daniel H., Tomsho, Lynn P., Auch, Alexander, Rampp, Markus, Miller, Webb, Schuster, Stephan C. (2006).
Metagenomics to Paleogenomics: Large-Scale Sequencing of Mammoth DNA
Science 2006 311: 392-394

Don't toss out the "Wastebasket" genera!

In the most recent issue of Paleobiology Roy E. Plotnick and Peter J. Wagner investigate the nature of common fossils that dominate most collections. By exploring the online database "The Paleobiology Database" they concluded that many genera of fossils are rare (15-25%) occurring only once in the database, while the 100 most common genera contribute to over 50% of the occurrences.

Is this an underlying biological reality or are there fundamental problems with how data from the fossil record is collected and compiled?

One of problems is that many fossil groups have not been systematically studied or revised in many years, leading to a large number of specimens being assigned to a particular genus with little regard to the validness of such assignment. These genera are often referred to as a "wastebasket" group (a term that I have seen in the literature as fall back at 1915). Plotnick & Wagner offer a nice definition of the term "wastebasket" and explain how such groupings may come about over time. Of course it is very difficult to conclude that a particular group is a "wastebasket" or not. By looking at the number of species within the group, plotted against the number of occurrences there is an almost linear relationship between the two. This implies that a problem might exist, and that when it comes to determining diversity in the fossil record one must be careful to examine the wastebasket carefully.

Plotnick, Roy E. and Wagner, Peter J. 2006. Round up the usual suspects: common genera in the fossil record and the nature of wastebasket taxa. Paleobiology, 32(1), 2006, pp. 126–146

Reptilian menagerie exposed, in yet another bizarre crocodilian.

A middle Mesozoic marine crocodilian skull discovered in the Andean foothills of Argentina, exhibits a rather unusual short face. Its massive teeth are supported by a round maxilla and dentary, reminiscent of later mosasaurs, which dominated the late Mesozoic oceans. Although not suggested by the researchers, this unusual skull morphology may likely have been an adaptation to preying on ammonoids, which first appeared in significant numbers at roughly the same period of time.

Gasparini, Zulma, Pol, Diego, Spalletti, Luis A. 2006. An Unusual Marine Crocodyliform from the Jurassic-Cretaceous Boundary of Patagonia Science 2006 311: 70-73

Clark, James M. 2006. PALEONTOLOGY: A Different Kind of Croc. Science 2006 311: 43-44

Humerus Found in Dinosaur Cove, Australia

A and B fossil humerus, C and D living Echina humerus

A mammal humerus from the early Cretaceous is morphologically similar to living Echinas (living monotremes). The specimen was described as part of a symposium volume in tribute to Dr. William Clemens, of the University of California, Berkeley.


Peter A. Pridmore, Thomas H. Rich, Pat Vickers-Rich, Petr P. Gambaryan, 2005. A Tachyglossid-Like Humerus from the Early Cretaceous of South-Eastern Australia, Journal of Mammalian Evolution, Volume 12, Issue 3 - 4, Pages 359 - 378

Thermometers spike in 2005, but as high as 1998?

Nine of the ten warmest years on record have occurred since 1995! 2005 stacks up to be one of the warmest years ever. It may even beat the record global mean temperture set in 1998. It will be an interesting century ahead of us as the ice begins to melt.