If god has an inordinate fondness for beetles, then he must surely hate ring species. As eminent evolutionary biologist, prominent god denier and all round good guy retired Professor Jerry Coyne notes in his blog, there are no ring species. Atleast no ring species that meet the textbook definition. He describes how genetic evidence has shown that even the most well regarded ring species have been shown to have some levels of allopatry.
Being a long time follower of his blog, why evolution is true as well as his numerous papers and books that have established the field of Speciation, i was over joyed to write a digest for journal Evolution around this topic. The other great name in Speciation, Trevor Price has worked on Ring Species making this one of those cool things that has captivated the imagination of very smart people. Barriers to gene flow and ring species formation is a recent article that uses agent based model simulations to show how ring species formation requires narrow corridors. These narrow corridors are highly susceptible to disruption due to local changes. Such disruption can result in allopatry.
"Tiny" amounts of allopatry can lead to a ring species not meeting the textbook definition. So obviously, god hates ring species :) and that is why he "designed" such a characteristic feature. On a more serious note, this paper does highlight the importance of using simulations in the field of Evolution. Hopefully, we will see increasing use of such approaches in the future.