Raptorex debate continues

In a previous post about Raptorex kriegsteini I expounded upon Jack Horner’s suggestion that Raptorex is not an example of the Tyranosaur body pattern evolving before gigantic size. Now, Horner and colleagues have published the data behind their critiques in PLoS One:

The recently described small-bodied tyrannosaurid Raptorex kreigsteini is exceptional as its discovery proposes that many of the distinctive anatomical traits of derived tyrannosaurids were acquired in the Early Cretaceous, before the evolution of large body size. . .These findings are consistent with the original sale description of LH PV18 as a juvenile Tarbosaurus from the Upper Cretaceous of Mongolia. Consequently, we suggest that there is currently no evidence to support the conclusion that tyrannosaurid skeletal design first evolved in the Early Cretaceous at small body size.

Fowler DW, Woodward HN, Freedman EA, Larson PL, Horner JR, 2011 Reanalysis of “Raptorex kriegsteini”: A Juvenile Tyrannosaurid Dinosaur from Mongolia. PLoS ONE 6(6): e21376. doi:10.1371/journal.pone.0021376

corREXion?

This article was originally posted at Science 2.0 on 21 April 2010 as a follow up to my article What Do Ardi, Raptorex, and Komodo Dragons Have in Common?. In light of recent debate* about Raptorex’s identity I thought this was worth a second look.

 

Raptorex by Nobu Tomura (GNU Free Documentation License)

 

Normally, being wrong sucks. It’s all -10 points and you don’t get into Harvard. Sadness. But, not in science. One of the best things about scientific method is that it makes being wrong fun. That does not mean that scientists always like to hear they are wrong. We are after all sinful, prideful beasts like the rest of you – just smarter – just kidding.

A while ago, I discussed some relatively recent, amazing contributions of paleontology in order to illustrate that, while DNA may trump fossils for reconstructing evolutionary histories and the relationships between organisms, paleontology provides information on physiology and geographical location that can only be inferred by other disciplines. One of the discoveries discussed was of a 125 million year old, man-sized Tyrannosaurus rex ancestor, Raptorex, reported in Science on 17 September 2009. Continue reading “corREXion?”

What Do Ardi, Raptorex, and Komodo Dragons Have in Common?

This article was originally posted at Science 2.0 on 9 October 2009. It provides some background for the follow-up article corREXion? that has suddenly become relevant again.

Paleontology doesn’t always get the respect it deserves (or desires), in the molecular, genomic, evolutionary, quantitative genetic circles we run in around here. Blame the DNA. Sequence comparisons have proven incomparable in establishing phylogenetic relationships between organisms.

Paleontology can also irritate us by creating false controversy, which irritates the heck out of us. The fossil record is a sparse and biased record of life. Supposed “missing links” are often an artifact of this fact. Supposed discrepancies between sequence divergence times and divergence in form from the fossil record often reflect the fact that sequence divergence necessarily precedes any differences in form significant enough to be noticeable in the fossil record.

This means that biologists tend to relegate paleontology (fairly or not) into the roles of adding colorful detail. Therefore, it is particularly exciting when there are not one, not two, but three recently reported fossils that force the biological community to re-evaluate evolutionary hypotheses. Continue reading “What Do Ardi, Raptorex, and Komodo Dragons Have in Common?”