Counting Unknown Hierarchical Kinds

A discovered technical paper just published in  Language Log.  About how to estimate kinds of things that exist in a hierarchical organizations.  The initial posed question is:  How many species exist on earth?  We do not know the exact answer, but would like to estimate it as well as possible.  Pointers to work by Turing and others in this space. Exactly this question came up when we sought to understand the communication of innovation in the enterprise. This paper would have helped the process.