Reptile & Amphibian Forums

Hello all,

I was just reading the posts below about trying to figue out if a milk was a Sinaloan or a Nelson's and was curious what the consenus (or at least opinions) was. So what do you all think, are they the same or different? and does it matter?

Vinny
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“There is a grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that whilst this planet has gone on cycling according to the fixed laws of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.” -C. Darwin, 1859

Vinny,

They are two different subspecies, just like eastern milks and Hondurans are two different subspecies. Nelson's and Sinaloans overlap in range and probably naturally intergrade. They also look very similar (Sinaloans have wider triads though). For this reason many hobbyists regard them as the same thing. From a scientific standpoint they are not and each has its own latin name.

Tim

Third Eye

But since the morphological characteristics that define each overlap, and offspring from a sinaloan mating can key out as Nelson's (and visa versa) does the subspecies distinction mean anything. After all, one of the hallmarks of a species is that it can not mate outside its own species and produce fertile offspring (at least the according to the strictest species definition), perhaps they are they are really same species with two different natural morphs (such as variation in graybands) and Latin names be damned.
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“There is a grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that whilst this planet has gone on cycling according to the fixed laws of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.” -C. Darwin, 1859

People have cross-bred rat snakes and pine snakes. These are not only completely different species, but different genuses as well - so that "hallmark" has no validity.

The things that taxonomists use to define species can be characteristics like scale count, skeletal structure and DNA - so just because something looks like something else, doesn't make it so. Until scientific evidence shows otherwise, Nelson's and Sinaloan milksnakes are two distinct subspecies - despite some hobbyists saying that they're the same thing.

Tim

It is a strict definition of a species (Mayr's), but they are others they are more flexible which include definitions like populations that avoid reproducing with each other are species (which would take care of the rats and pines). Are the offspring of the ratXpine fertile?

>>"The things that taxonomists use to define species can be characteristics like scale count, skeletal structure and DNA - so just because something looks like something else, doesn't make it so. Until scientific evidence shows otherwise..."

I guess that is my point. Scale counts and pattern variation cannot be used to identify either "species" in this case since the variation in these characters is so great (and can be different between parent and offsping), and, unfortunately, DNA-based work has yet to be done. So in the absence of definitive evidence should the default be to lump together or to split apart (I guess you are a splitter).

Vinny
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“There is a grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that whilst this planet has gone on cycling according to the fixed laws of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.” -C. Darwin, 1859

I believe the rat/pine snake offspring are fertile. I am not a fan of hybrids, so I do not know for sure.

My "separate subspecies" point is that Nelson's and Sinaloans are considered separate subspecies by taxonomists. There are reasons for this. I do not think casual hobbyists have the authority to reclassify subspecies as they see fit. Your original question was if Nelson's and Sinaloans are the same thing. The answer (until further notice from the sector of the scientific community dedicated to classification of animals) is that they are not.

Tim

Sinaloans and Nelsons are without doubt the same species. They are often, however, considered to be different geographical morphotypes ("subspecies" or "pattern classes" are equivalent phrases). The sinaloae pattern class tends to be found in the Mexican states of Sinaloa and southern Sonora. The nelsoni pattern class tends to be fround in Jalisco, Nayarit, and Colima.

All Milksnake subspeces have wide zones of intergradation where they abut. Thus, there are no sharp boundaries between subspecies. The tendency of a population to adhere to a particular phenotype which can be distinguished from other populations within the species defines a subspecies. Do nelsoni and sinaloae adhere close enough to different phenotypes to be considered seperate subspecies? Ken Williams says "yes", others say "no" . . . Here-in lies the debate. Hope my ramblings helped.

-Cole

All opinons help. I have Williams' "Systematics and natural history of the American milk snake...", do you know of other refs (particularly those on the other side)?

Thanks
Vinny
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“There is a grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that whilst this planet has gone on cycling according to the fixed laws of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.” -C. Darwin, 1859

Williams' book is by far the most complete on the species Lampropeltis triangulum and its various subspecies. It was he, after all, who proposed the recognition of L.t.sinaloae for the north-western most populaton of milks in Mexico. I've heard other systematic publications on triangulum are in the works. Perhaps others have more detail on this?
-Cole

I know there is a molecular phylogeny comming out in a few months, should be intersting to see if it can differentiate nelsons from sinaloans.

Vinny
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“There is a grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that whilst this planet has gone on cycling according to the fixed laws of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.” -C. Darwin, 1859

I think a few breeders have forgotten some very important information about these two species. Several years back when tri-color milks were all the rage and albino nelsons were commanding big bucks, there were problems due to inbreeding. It was common knowledge that nelsons could be bred at 18 months or less. Just my opinion from what I have seen but breeding too soon results in smaller adults, smaller clutches, and smaller hatchlings. The inbreeding continued without regard to negative results. Then we started seeing the crosses supported by the fact that nelsons and sinaloans are a natural intergrade. Several big breeders started doing this. I believe it was their way of finally addressing the problems listed above as well as some other problems from the previous years of inbreeding. Because they cross in the wild, nobody slammed it as a mutt. I recall that one of the largest producers posted on his website that none of his stock would be pure in the future. All of his stock would be nelson/sinaloan crosses. If only they had stopped when they saw the first problems fron inbreeding. The money was too much, the ability to breed at 18 months, etc.
Just the way I remember it.
John Q

Thanks for the info. If many sinaloan/nelsons crosses were done in the past it may no longer be possible to tell them apart making the whole thing no longer applicable for snakes from old breeding stock.
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“There is a grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one; and that whilst this planet has gone on cycling according to the fixed laws of gravity, from so simple a beginning endless forms most beautiful and most wonderful have been, and are being, evolved.” -C. Darwin, 1859