Added support for Gish's argument is the recent discovery in western Argentina of what may be the largest meat-eating dinosaur known, a 12.5-metre-tall dinosaur christened Giganotosaurus carolinii (Nature, Sept. 21 [1995]). Despite the overall similarity in appearance to T. rex, according to Argentinian paleontologist Rodolfo Coria, Giganotosaurus was not related to it, and the two beasts "arose independently".

Mr. Poling:

What does the mere existence of Giganotosaurus or its similarity to T. rex have to do with the supposed lack of transitional fossils? This is a poor argument to say the least ... a blanket statement without explanation. The only thing I can figure is that you are trying to use Gish's argument to say that different animals cannot evolve similar forms if they are unrelated. As presented, Gish's argument says no such thing. Indeed, extant animals, such as the Tasmanian Wolf and the North American Wolf, show that it quite possible and indeed probable that unrelated animals in similar environments will evolve similar form.

Addendum:

Giganotosaurus is better known today. It is an carcharodontosaurid allosauroid, sharing a close common ancestor with Allosaurus and belonging to the same family as the african giant Carcharodontosaurus. Allosauroids are not closely related to tyrannosaurids and, except in ways that make them both avetheropods, are not very anatomically similar. They share a few features due to adaptation to their great size, but a dinosaur paleontologist, or even an experienced amateur, would have no trouble distinguishing between the two giants.