Hmmmn well Cole... "temporalis" as a product of a secondary intergrade zone wholistically I'd have to disagree with... lol. Aside from that nice instigatory post! I feel more data concerning the actual migration of the varied subspecies to their currently occupied habitats lends some nice perspective as well. Factor in some cool avg. global temperature shifts and we may find the notion of a truly 'pure' primary intergrade zone to be a rarity. Imagine tossing a few pebbles on some calm water and watching the concentric rings meet and overlap. I'd imagine Shannon is indeed right.... aside from locality all we have are NA milks from varied places.



Where do you mix in taylori in this scheme? Or even celaenops now... I'm sure this will get struck up a bit next time we talk as I'm already finding my expression limited by my slow 'two fingered' typing technique! Anyhow here are three 'temporalis' that may in fact have three distinctly different evolutionary processes...



Chris! This is exactly what I was hoping for!



Let me start at the end of your post and work backwards...



I think we may be seeing 2-3 different processes going on with what we’re calling collectively “temporalis” at the moment, too. Some of the animals are, from what I hear, genetically indistinguishable from syspila and nominate triangulum. These animals, as we know, also LOOK a lot like syspila and are found in the northern portion of “temporalis” range. Other animals, especially the ones from further south, are genetically indistinguishable from elapsoides (which doesn’t seem to cluster with any other milks in genetic studies… suggesting it’s NOT part of the triangulum group). Now, assuming that the Northern and Southern populations actually interbreed somewhere along the coastal plain, we’d have either secondary intergradation (assuming elapsoides is a triangulum that has been isolated by past Climatological events) or introgression (if elapsoides is no longer part of the triangulum group).



So, to sum it up, we may have “temporalis” that are really derived from syspila and nominate triangulum, “temporalis” that are derived from elapsoides, and “temporalis” that are a mixture of the two. I’m assuming you’ve read the same compelling arguments recently that I have… LOL



OK, on to the next topic… primary vs. secondary intergradation!



I don’t find much compelling evidence to suggest that the western milks (taylori, gentilis, multistrata, celaenops, and annulata) are currently, or ever have been, separated from one another in any way enabling them to evolve along separate trajectories. Genetic material has rendered them indistinguishable, and there is current gene flow between all of these adjacent populations. For instance, suitable milk habitat is found in south-western WY, adjacent to UT. Milks have been sighted in that area, though I’m unaware of any vouchered specimens. This suitable habitat is continuous to the south to known taylori haunts, and north, to known multistrata haunts. We find similar situations to the south, were more and more AZ specimens are turning up.



And this brings us to the last point!



It’s my personal feeling that taylori is physically indistinguishable (“average” number of bands is, honestly, an outdated and useless character for identification) from celaenops, gentilis and multistrata without locality data. Taking another step, multistrata and gentilis are indistinguishable from one another, as are celaenops, annulata and amaura. A “subspecies” without discrete diagnostic characteristics (physical or biochemical) is rendered invalid under standard nomenclatural practices. All of the above are, necessarily, subject to the rules of priority and sunk into gentilis (I believe it’s the first named, anyway).



Now, a qualifier: I find the above subspecies designations useful in providing a reference to geographic origin and “typical” appearance of a given animal. Since this is the basic purpose of a subspecies designation, should they really be dropped? I don’t know… LOL



How does syspila fit into this? Well, I’d reason that syspila and nominate triangulum became isolated from the western milks (here-in gentilis) during one or more of the previous glaciated periods on the North American Continent, coming back into contact with one another in the interglacial period(s). This has resulted in the differences we now see between “eastern” milks (syspila and nominate triangulum) and the western forms regarding morphology and ecology in addition to genetics.



-Cole

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