Hi Linda About 6 years ago when I was working with a researcher from San Francisco State Univ - Conservation Genetics Lab. Calliostoma parsimony analysis via molecular CO1 study. We discussed some research that had been recently completed on the M. radix - nigritis complex. The findings were interesting: Generically speaking they are all one species. Populations were systematically sampled all down the west American coasts and their DNA analyzed. From population to population there was no significant difference in the DNA from one population to the next. However, when you make large jumps, say from mid- California to Baja, there was enough difference to possibly conclude they could be differnt species. There is no dividing line between one species to the next, just a slow minor but progressive change in the gene pool from one colony to the next. In short, it points out the relativity of even using molecular study to determine speciation. As we all know shells tend to be extremely variable, and things such as temperature, food sources, and trace elements can be a big factor in a shells looks, and population isolation repeats characteristics differentiating one colony from another. ...Even though the guy in the cubicle next to you may seem like another species... he is still the species Homo sapien. Unfortunately I do not know what the citation is for this study, it was probably someone's doctoral dissertation. I have not spoken with, or been able to find the researcher in many years, so even the work he was doing for me I can not attain. As for me I do not have a problem with names on distinct forms. That is the beauty and essence of Shell Collecting.... and the systematicist will continue to change names, create new name, synonymize them, and restore them again until eternity. So have fun and enjoy the shells!!! Best Regards, Leslie Allen Crnkovic -------------------------------- Hello, CONCH-Lers! I think I know why my confusion. Instead of having mixed up the localities, I apparently have nigritis and ambiguus, not nigritis and radix. I failed to consider ambiguus as a possibility for the one species. Thanks, Linda P.S. Now all I have to get is a specimen of Radix, so that I have the three species to examine (assuming that ambiguus has specific status).