Very Common question Mr. Creationist.
I hear this argument almost everyday, often the simplest answer is "read a book" or "please visit a museum"
The fact of the matter is that transitional fossils are in abundance. I agree, there might not be as much as we should expect, however that is due to many different factors: environmental, positional, geographical and many other technicalities which diminish the number of fossils that are found or that will be found.
Anyway, back to the matter at hand....."where are the transitional fossils, 'evilutionist'?"
In this article, I'll just highlight a few of the hundreds...thousands of transitional fossils found.
Before starting i think it is IMPERATIVE that I highlight that there is a difference between TRANSITIONAL and INTERMEDIATE. As usual, I aim to make this as simple as possible as to equip atheists in presenting this data as accurately and simple as possible to creationists. let me put this as simple as possible:
Now an INTERMEDIATE form is one that DOES have a large number of uniquely "derived traits", not connected to its derived relative..In other words INTERMEDIATE forms are uniquely different from their ancestral relative. I hope you understand this.
A TRANSITIONAL form, is one that may have unique traits that the derived relative does not have but is still very similar to its ancestor.
for example, the well-known TRANSITIONAL fossil; ARCHEOPTERYX does not show any derived traits that more derived birds do not possess as well. In contrast the PLATYPUS is intermediate, because it maintains certain reptilian traits no longer found in modern mammals and also has traits of a highly specialized aquatic animal. Using this definition, ALL living organisms, including you and I are intermediate forms, but not transitional....get it? I hope you do..lets move on.
This is the part of this blog I'm going to have a problem with because there are SOOO many transitional forms that picking one or two is..just..ugh. Anyway I'll pick a few of my favourites.
1. Panderichthys, Elpistostege (mid-late Devonian, about 370 Ma) -- These "panderichthyids" are very tetrapod-like lobe-finned fish. Unlike Eusthenopteron, these fish actually look like tetrapods in overall proportions (flattened bodies, dorsally placed orbits, frontal bones! in the skull, straight tails, etc.) and have remarkably foot-like fins.
-taken from talkorigins.org
This fossil shows the ever so important link between bony fish and amphibians
2. Dvinia [also "Permocynodon"] -early cynodont. First signs of teeth that are more than simple stabbing points -- cheek teeth develop a tiny cusp. This fossil shows the ever so important link between Reptiles and Mammals.
I could list literally thousands more..for more info and transitional fossils visit http://www.talkorigins.org/faqs/faq-transitional.html
When all is said and done, transitional fossils are very much available and observable. Please advise the person you are debating with to visit a museum as well as pick up a book and read. The evidence is very much there, they just don't want to believe it.
Again...good luck arguing with these dumb-asses