Ben,
Ill get you that paper, you have a fax number?, if so email it to me.
Chuck,
the best way to tell granuliferus apart is as silverstone says distribution. I would say more specifically habitat, niche preferance etc. granted this doesnt help if you have frogs with sketchy or no collection locality data. grannies you will find almost exclusively in deep cut stream valleys, steep slopes, with thick leaf litter and lots of diefenbachia with which tads are raised. You can walk through miles of good looking rainforest but wont find the grannies untill you find the streams (I have done this) The streams are usually characterised with large boulders, which they take refuge between to stick out the dry season. Distribution of granuliferus is more widespread in Pacific CR than most people realize, and its variability in colour and size is not fully appreciated, some of the more northern pops get quite large, some males reach probably 27mm, maybe more, and in some of these north western pops. it appeared males were the larger sex. I guess this is kind of getting off track...The daly paper is interesting, and i think the jury is still out as whether this is an introduced pop, or a natural one. If it is indeed not introduced as the authorors speculate the occurance of granuliferus on the atlantic is far from the norm. I tend to agree with justin that it may be introduced, but the apparent remotness of the region keeps me speculating.
the call is quite different, longer cheeeeeeeeeeeps as opposed to the more rapid cheeep cheep of a pumilio. I would say size is another one and believe Silverstone erred to the small side with 19 - 22 mm, I imagine he was working with a palmar, or golfito population, which are smaller than some of the pops from the northern extremes.
so getting back to the question how do you visually tell them apart, the best way is the intense granulation, which really does surpass any granulation I have seen on any pumilio pop, they really do look look different when you see them both up close. The individule "granules" are larger on granuliferus. Ryan says they ae rounder, and justin says longer, I would say they are more robust, or stocky, which may sound strange now, but if you ever get the oppurtunity to see both of them side by side, or spend enough time with either of them the difference will be clear. but again as you suggest it can be difficult to go on appearance alone, whcih bring us to the importance of locality data, and keeping track of lineages and all that fun stuff.
I dont belive i actully clarified anything, hopefully didnt add to the confusion, but granuliferus is such a fantastic frog it brough me out of lurking.