Mike,
Geographic range identification of greens based on postocular stripe coloration is definitely a controversial issue. That said, I have personally seen at least 50 to 60 photos of E. murinus, with accompanying location data, and have noticed a very definite pattern of distribution with regards to postocular stripe color. Orinoco basin specimens did show some well defined shade of yellow or orange coloration in the postocular stripe virtually 100% of the time. I have never seen a photo of a murinus that originated from the Orinoco basin that had the relatively solid background green coloration of the postocular stripe. A great photo example of this green ocular type can be seen in the 3rd and 6th photos in the December 12th post by Ben Renick.

Conversely, I would say that about 90% of the greens with Amazon basin locality data I have seen photos of, did show the relatively solid green postocular stripe. The other roughly 10% did have a very small amount of yellow or orange in the postocular area.

I would never say that the postocular stripe coloration could be used to determine the major river basin of origin with 100% accuracy. But I do believe that it could be used to give a fairly good probability of the most likely basin of origin. The one issue then remains within the spectrum of postocular color types, and that is the small percentage of those which fall into the intermediary color group. Unless capture location data are available, these will always be problematic, as I don’t believe there are any other morphological traits that can be used to distinguish between the two populations at this time.

That female yellow of yours is incredible. Do you have any weights on her just before ovulation each year? I would be curious to see if she is actually heavier each consecutive year, or if she is just maintaining her same weight from year to year.

Kelly

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