You're right bagginsbill, increasing shadow min bias was one way to lessen the artifacts (with a corresponding loss of shadow quality)... another way that I've found to eliminate them entirely was to disable smoothing by setting all smoothing (in properties settings) to none and setting crease angle to zero. this, of course isn't an acceptable way to render an organic object so it's not really an option.

What's peculiar is that my shadow min bias for raytraced shadows is usually set around 0.3500 which is a happy medium for me because lowering the value generally produces the polygonal shadowing that you speak of and raising the value results in a loss of shadow detail and granular looking shadows. I recently did a render with 0.350000 min bias, 5 blur radius, 50 shadow samples, shadow strength of 8 and the artifacts did not appear. If, however I use my old settings which were 0.350000 min bias, 5 blur radius and 20 shadow samples, (same object) I get the mesh artifacts. I don't know what combination of settings is really causing this but I plan on tracking it down. I was convinced that maybe it was some problem with Poser 8 as I don't recall this phenomena in poser 7.

Most of my knowledge about raytracing with Firefly comes from Blackhearted's "Firefly Render Settings and Tips" tutorial pdf (all of his suggestions seem pretty sound in practice to me) and the information in the Poser Reference Manual.

Thanks for the links, which would have been difficult to locate as I'm not really quite sure what the problem was (is) to begin with. Hence, I wouldn't have known where to search. I'll make sure I read all of your observations on Firefly.

Thanks for taking the time to address my confusion, BB!