Reptile & Amphibian Forums

I was just wondering if there are any subspecies in the yellow anacondas, like there are in the greens (E m murinus and E m gigas).
Thanks a lot.
Jonas

Jonas,
Eunectes notaeus has yet to be split into subspecies and I have never seen any indication that it will be in the future. Thanks,

Kelly

I thought that there was a subspecies mentioned in that nice
Boa book, I can't remember the title. It's pretty thick and
in hardcover. I'll check tonight when I get home.

It may have said something about one being brighter yellow and slightly smaller. Maybe it was a regional variation and not a
legitimate subspecies....

For that matter I have yet to be able to find anyone that can definatively outline the phisiological differences between E.m. murinus and E.m. gigas.

GD
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I don't believe in luck. Luck is God covering your a** when you screw up.

Gary,
There are only very slight morphological differences between E. m. murinus and E. m. gigas, and there is a debate on whether they are even valid subspecies of E. murinus. According to study data in the literature, the ventral counts, dorsal scale rows, subcaudals, supralabials, and infralabials of each do not show enough variation to be significant. It has been reported however, that murinus appears to reach a slightly larger adult size than gigas. The only other difference in appearance that is visibly discernible is that gigas, or the northern form, does tend to show yellow or orange, in the postocular stripe to a much greater degree than is seen in murinus, the amazon basin form, which tends to have a postocular stripe that closely matches the green ground color of the animal. I have seen a few live anacondas and many in photographs that seemed to have accurate locality data, and this postocular color theory appears to hold true with the vast majority of the specimens, although there have been a few exceptions. Now whether they were true exceptions or just had faulty locality data is not known.

Kelly

You're absolutely right Kelly. The differences you described are the ones I was aware of, but I too do not think that sufficient for designation of subspecies. I was hoping someone would have a tangeable and difinitive deliniation such as subcaudal scale count, etc. Really, on the basis outlined to us, there is more variation of Boa constrictor imperator morphology than Eunectes murinus ssp.

GD
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I don't believe in luck. Luck is God covering your a** when you screw up.

Gary,
You are correct about the variation seen within the Bci but that is due to the large range of the subspecies and the varity of different habitats in which it is found. E. murinus is also found over a large area but is found in relatively similar habitat throughout the majority of it's range. Additionally, this habitat has remained fairly stable for tens of thousands of years over a large part of this range. Therefore, E. murinus has probably not had the variety of selective pressure across it's range, over a long enough period of time, required to produce enough change in morphology to clearly differentiate the two subspecies by current standards. Some may see it differently but just my thoughts on the subject.

Kelly

` My take on the various morphologies among the species, and even sub-species of the Boid genera, compares them with Humans. We are a trinomial, Home s. sapien. Within our sub-species are many races, and sub-races, with quite different morphologies, to our own eyes. Even given our vast range, there are differing races living in common areas. Yet, we interbreed, and produce viable offspring. We are basically the same critter.
` A species covering a vast area, such as Boa constrictor ssp., or Python reticulatus, or the short tailed Pythons, has many more races than sub-species. They can be morphologically quite different, without necessarily being insular.
` Even though the Yellow Anaconda comes from a relatively small range, I have seen several distinct racial representatives. The same applies to Green Anacondas.
` In my opinion, they don't necessarily have to qualify as a separate sub-species, to have quite distinct racial traits.
` It would be a treat to explore their range, and describe the various races. Oh well, maybe next time.

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I understand what you are saying, but in the case of E. murinus, I see it similar to Gary D. I don’t believe there is enough consistent morphological variation, with any measurable characters, that would warrant subspecies classification. The postocular stripe color and adult size differences could easily be geographical variations of murinus, and not justify subspecies (race) classification. There are currently four species recognized within the genus Eunectes and I don’t believe there are any generally accepted subspecies in the genus. It is a group that has not been studied very closely until fairly recently.

Kelly

Hi Kelly,

Do you know which is the subspecies most known in captivity between E. murinus murinus and E. murinus gigas?

Thanks!

The northern form (gigas) appears to be the more common type found in captivity today. This also makes sense due to the origin of most of the imports. Just my opinion from what I have seen lately.

Kelly