or Another Fine “Messasaugus”
When modern systematists are forced to rely on data and specimens originally gathered by some of the explorer naturalists of almost two centuries ago, they may be somewhat frustrated by the seemingly cavalier attitudes that such men displayed toward the now sacrosanct entities of type specimens and type localities. One of these early North American naturalists, Constantine S. Rafinesque, who plays prominently in this episode, has even been accused of eating the type specimens of certain fishes he would later describe – from notes – as new species. Considering the harsh conditions these pioneer-naturalists often labored under, however, it is remarkable that they were able to record, collect, and accomplish as much as they did.
Traditionally when modern reviewers encounter problems with the types and type localities of taxa described during this earlier period of North American herpetology, they attempt to narrow down (restrict) vague type localities and, should the type specimen itself be lost or missing, designate a new, replacement type specimen (neotype) collected from as near the original or newly restricted type locality as possible.
Enter Dr. Andrew Holycross of Arizona State University and his colleagues. For whatever reasons, these gentlemen were examining the three species of rattlesnakes described by the aforementioned C. S. Rafinesque in 1818. One of Rafinesque’s new species “from the barrens of Kentucky,” “Crotalinus cyanurus,” had been determined by previous workers to be the same (a junior synonym) as the Timber Rattlesnake (Crotalus horridus) and is of no further concern here.
The other two rattlesnakes described by Rafinesque, however, were indeed new to science at the time: “Crotalinus viridis” (now the Prairie Rattlesnake, Crotalus viridis) and “Crotalinus catenatus” (now the Massasauga, Sistrurus catenatus). The type specimens of both these species have long been lost or were never designated, and to make matters worse, the published type localities of both were exceptionally vague: “Crotalinus viridis” was merely said to be from “the Upper Missouri” while “Crotalinus catenatus” was from the “prairies of the Upper Missouri.” Additionally, the authors assert that Rafinesque apparently transposed even these vague localities in his original descriptions for the respective species, in that “prairies of the Upper Missouri” given for the Massasauga, would actually be more consistent with the habitat of the Prairie Rattlesnake, as would be “the Upper Missouri” for the Massasauga.
Resorting to details contained within the unpublished correspondence and published accounts of the travels of the actual collector of both specimens, John Bradbury, Holycross and his associates determined that Bradbury had collected the type of “Crotalinus viridis” in what is now North Dakota, outside the range of any other species of rattlesnake. Thus they were able to restrict the type locality of this form to “the prairies between the Cannonball and Heart rivers, within 40 km of the Missouri River in North Dakota.”
The type locality of “Crotalinus catenatus” was subsequently also restricted to “the floodplain of the Missouri River, between the mouth of the Platte River and Nebraska City, Nebraska.” Only one other species of rattlesnake (the Timber Rattler, Crotalus horridus) occurs at this locality, but the researchers were convinced that Rafinesque had actually been referring to the Massasauga in describing his “Crotalinus catenatus” from notes. Thus the confusion regarding the type localities of the Prairie Rattlesnake and the Massasauga was resolved.
However. . .
The type locality of the Massasauga, as no doubt correctly discerned by this study, now incontrovertibly falls within the range of the subspecies long known as the Western Massasauga (Sistrurus catenatus tergeminus, originally described as a full species by Thomas Say in 1823). In other words, the description of the type specimen of S. c. catenatus was based upon a specimen of S. c. tergeminus.
According to the Principle of Priority (International Commission of Zoological Nomenclature, 1999, Article 23), the race formerly known as S. c. tergeminus would now become the nominate race for Sistrurus catenatus since Rafinesque had described it in 1818, five years before the same species was described by Say as “Crotalus tergeminus,” which would then become a junior synonym of S. catenatus. Had Say described his form first, the Massasauga would now be known as S. tergeminus. The race known as the Eastern Massasauga (long the nominate race, S. c. catenatus) would then acquire the unfamiliar name “messasaugus,” as used in a description by Kirtland in 1838, the first such of the eastern form.
Fortunately, a paper exists, published by Kraig Adler in 1963, which examined the question of the type locality and correct spelling of Kirtland’s name for the eastern form. Adler concluded that a specimen in the U. S. National Museum (USNM 526) “could” be Kirtland’s type specimen for his “Crotalus messasaugus,” in which case the type locality would become “Poland, Mahoning County, Ohio.” Additionally, Adler presents evidence that the peculiar spelling, “messasaugus,” was actually a misprint, since Kirtland used the correct “massasauga” spelling in several other places in the paper. Evidently, in such cases the ICZN now allows for a misprinted name to be corrected. It appears that the authors’ statement, “our interpretation of the Principle of Priority (ICZN, 1999, Article 23) renders the scientific name of the eastern form as Sistrurus catenatus massasaugus,” may suffice to make it so.
Recent editions of the ICZN code, however, have taken a dim view of the time-honored practice in taxonomy of upsetting nomenclatural stability by asserting the priority of an obscure re-discovered name that might have technical and temporal precedence over a younger name that has enjoyed long-standing application and acceptance. In such cases, the ICZN has stated, the interests and benefits of taxonomic stability now trump strict adherence to the primacy of priority.
Recognizing the long and stable history of the names Sistrurus catenatus catenatus and S. c. tergeminus (more than 200 citations by more than 100 authors during a span of well over 50 years), the authors are attempting to retain the subspecific names as currently used via an unorthodox appeal to the ICZN. They propose to designate a neotype (possibly USNM 526) for the species Sistrurus catenatus from Adler’s restricted type locality for the Kirtland name “Crotalus messasaugus” (i.e., Poland, Mahoning Co., OH), retaining Rafinesque’s familiar name but in effect discarding his problematic type locality. If accepted by the ICZN, this proposal would suppress “S. c. massasaugus,” keeping the eastern race as the nominate form. Until the ICZN renders a decision, the authors advise adherence to “existing use” for names within this species.
Interestingly, Holycross et al assert that Howard K. Gloyd, an expert rattlesnake taxonomist who reviewed Sistrurus catenatus on at least three prior occasions (1940, 1948, and 1955) must have been aware of the problematic nature of the species’ type locality. They offer the suspicion that “Gloyd’s subsequent silence on this topic was due to his natural conservatism and a desire to see what information could be construed from additional specimens. In this sense, we believe Gloyd would have dealt with the nomenclatural issue only if (and when) that issue was forced.” It should also be considered that Gloyd was working in an era before the ICZN was as committed to the promotion of stability over strict adherence to priority as it appears to be today. Even Gloyd’s great “rival” in the field of rattlesnake taxonomy, Lawrence M. Klauber, was occasionally known to upset nomenclatural stability by resurrecting long-forgotten names for established taxa. Perhaps Gloyd’s “conservatism” was merely an appreciation for the value of taxonomic stability according to the aphorism “to let sleeping dogs lie.”
For taxonomists, particularly phylogeneticists, who tend to eschew the concept of subspecies anyway, the above nomenclatural changes would no doubt be of little interest, since all the changes are centered on subspecies; Sistrurus catenatus, the species, would remain taxonomically unaffected and would even retain the same (restricted) type locality. Given the intimations within this paper that phylogeneticists have determined that the eastern and western forms of the Massasauga consist of “deeply divergent . . . clades,” which basically conform to the current subspecies catenatus and tergeminus, the above appeal to the ICZN would also serve to conserve at least some name stability when the Massasauga is inevitably split into Sistrurus catenatus and S. tergeminus.
Source: Holycross, Andrew T., Anton, Thomas G., Douglas, Michael E., and Darrel R. Frost. 2008. The Type Localities of Sistrurus catenatus and Crotalus viridis (Serpentes: Viperidae), with the Unraveling of a Most Unfortunate Tangle of Names. Copeia 2008 (2): 421-424. [PDF]
Thanks to The Center for North American Hepetology for hosting the PDF of this paper
Thanks to The Center for North American Hepetology for hosting the PDF of this paper