Euphydryas phaeton clarki Pavulaan, 2021

Euphydryas phaeton clarki Pavulaan, 2021 nomen novum

The subspecific name Euphydryas phaeton clarki is proposed to replace Euphydryas phaeton schausi ( Clark, 1927) , preoccupied by Melitaea schausi (Godman & Salvin, 1901) which is presently considered a subjective synonym of Chlosyne definita definita (E. Aaron, 1885) . The same data (i.e., holotype, type locality) from the description of E. p. schausi ( Clark, 1927) applies to clarki (I.C.Z.N. Code Article 60.3). The name clarki recognizes Austin H. Clark, who first described schausi .

Comparison of the four described subspecies Conclusion

E. phaeton appears to consist of a broad cline from northeast ( borealis) to southwest ( ozarkae) ( Fig. 6). The subspecies borealis ( Fig. 5) is smallest, characterized by its glossy, pure black dorsal ground color and sharply-defined, deep red markings. Subspecies ozarkae ( Fig. 5) is largest, characterized primarily by its very reduced deep orange markings, the marginal ones of which are rounded and display faded edges. Host and habitat presently define this subspecies. Subspecies clarki ( Fig. 5) is phenotypically most similar to ozarkae. Where clarki transitions into ozarkae remains to be studied. The two subspecies may overlap by their habitat (dry upland vs. wetland) and primary host ( Chelone vs. Aureolaria ) choices. However, this may be unreliable as dry upland Aureolaria -associated populations tentatively identified as ozarkae have been documented in the east, especially in northern Georgia and Alabama.

Nominotypical subspecies phaeton ( Fig. 5) is most similar to borealis but is clearly a transitional form between borealis and clarki. It is highly variable, characterized by well-developed interior orange markings. A small percentage of specimens could be assigned to either borealis or clarki. Thus, authors who simply compare subspecies phaeton to borealis might be tempted to dismiss borealis as nothing more than a variant, or synonym, of phaeton . Similarly, authors who simply compare subspecies phaeton to clarki might be tempted to dismiss clarki as nothing more than a variant, or synonym, of phaeton . However, when comparing subspecies clarki to borealis, the contrasting phenotypes are obvious. Despite the temptation to synonymize the names of populations within clines, especially transitional phenotypes in the middle of a cline, does this suggest dropping nominotypical phaeton from usage? Per rules of the I.C.Z.N., once a nominotypical taxon is described and named, that name permanently applies to that taxon, even if synonymized. But recognizing the clear differences between populations at the ends of a cline merits their recognition as named entities.

Species E. phaeton presents a challenge to taxonomists and evolutionary biologists. The mechanics of a cline in this species calls for further study. Relationships need to be thoroughly studied among different habitat and host-associated populations.