Of interest to viewers of this blog, Annalisa Berta and I have recently published a taxonomic revision of this group
http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2907.2011.00193.x/abstract
A more detailed dissection of changes is presented in this blog post
http://www.birdforum.net/showthread.php?p=2247796#post2247796
no new splits at species level, but quite a few lumps at subspecies level (and a few at species level)
