Dear Brad,
I will say yes and no. We are limited in our investigation by the fact that we only have fossilized parts of past species.
Paleospecies are only known by that. This is true, unfortunately.
To take account of this subjetivity, it is assumed that mutations have always occured but have not changed the phenotype is most case.
Chronospecies are the best examples.
This inaccuracy is a parameter. A step ahead in objectivity?
Have a nice day,
Denesha