Utiger et al. have resurrected/erected about a dozen genera to accomodate the pieces of the genus Elaphe that they splintered because of paraphyly. These dozen or so contrived genera cannot be defined and they provide no definition for most of them. Why do they do it? It is because anyone who wants to follow Willi Hennig's classificatory philosophy is forced by Hennig's methodology to recognize contrived taxa. Herpetologist James D. Lazell comments on a similar case of "contrived" taxa regarding the iguanid lizards in the following quote:

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The methodology of Hennig makes difficulties for herpetologists studying groups like the large iguanines....

It appears that a complex of living forms, all allopatric and all extremely similar, have simply retained symplesiomorphies: 'possum-like' they have remained like their common ancestor and like each other (one may speculate that in the absence of sympatry there has been no pressure to diverge). Meantime, more up-to-date evolutionary departures have developed in the central, continental portions of the group's range. These have diverged and become morphotypes we would like to call genera (Sauromalus and Dipsosaurus). Recognizing them as valid genera leaves Iguana sensu lato "paraphyletic." Thus, the cladistic methodology forces species most like the ancestral stock (and each other) into contrived "genera" which cannot be consistently defined. This is a disservice to those of us who are interested in the real biological relationships of the animals, which are quite unaffected by evolutionary events in other lineages, regardless of time of speciation.
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Similarly, the many species of Elaphe found in the Old World and New World have remained morphologically similar to their common ancestor and like each other. Meanwhile, in the New World, more recent evolutionary departures from this ancestral morphotype have developed in the forms of Lampropeltis, Pituophis, Rhinocheilus, Arizona, Stilosoma, Bogertophis and Cemophora. Recognizing these genera leaves Elaphe sensu lato "paraphyletic." Thus cladistic dogma forces species like the ancestral stock and each other into contrived genera such as "Pantherophis," "Pseudelaphe," "Euprepriophis" which cannot be consistently defined. This is a disservice to us who are interested in real biological relationships among the ratsnakes, which are unaffected by evolutionary events in other lineages such as Lampropeltis and Pituophis.

Reference
Lazell, J.D., Jr. 1989. Phylogenetic systematics of iguanine lizards (Review). Copeia 1989:807-809

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