Chris Clowes: a number of book reviews, much of the Precambrian material & whatever else we can steal from his personal site, Peripatus.
Christopher Taylor: Bacteria, many basal deuterostomes, and some Eukarya. Discoverer of Pantopsalis phocator.
Jcwf: a few entries.
Mikko Haaramo: almost all of the cladograms except vertebrates.
M. Alan Kazlev: almost everything, particularly invertebrates and the time pages; design & layout.
Renato Filipe Vidal Santos: cleaning up, sourcing, streamlining and general niggling.
Roger Perkins: really too soon to tell, but I'll probably start with the Cambrian Explosion and provide a lot of pretty pictures.
Toby White: vertebrates, a few time pages, Eukarya; editing, previously updating & maintenance.