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Perhaps of interest to some (but was never a Field Guide)...

"Dogs have been our companions for thousands of years. This long allegiance and our preferences for dogs with certain traits have led to an unmatched degree of morphological variation and an opportunity for geneticists to unravel how genes interact with selection to shape phenotypes. Recent work in this area has revealed much about the genes underlying specific traits, such as coat color, foreshortened limbs, and hairlessness. Boyko /et al./ have examined variation at over 60,000 single-nucleotide polymorphisms in 80 dog breeds, African village dogs, and wolves. Interestingly, they found that the majority of variation among breeds was generated by just a few genomic regions of large effect. For example, they identified only six regions associated with body size, and ear floppiness was associated with just a single region. They hypothesize that the small number of regions controlling such a large degree of variation is probably due to the repeated bottlenecks dogs went through in their evolution, first when they were domesticated and then during breed development. Genetic diversity measures support this hypothesis, as all breeds displayed much lower genetic diversity than either wolves or village dogs. --/PLoS Biol./ *8*, e1000451 (2010)."

A genome selected to be morphologically plastic, Fido is... albeit artificially.

This could happen "naturally" as well. A basal genome that is driven by species recognition (see Horner and Padian -- "The evolution of ‘bizarre structures’ in dinosaurs: biomechanics, sexual selection, social selection or species recognition?" in J. Zoo.) would benefit from such plasticity, especially in areas that enable visual differentiation, in the sense that a ready path to morphological diversification and subsequent speciation could further habitat exploitation. I propose the resulting 'clutch' of related species be called a 'genus' ... er, never mind.

I suggest (again) that imprinting is a mechanism in extant animals which both highlights the importance of species recognition as a tactic and levers aspiring young critters into a morphologically exaggerated future -- as in, "Wow, you look even more like Mama than Mama does."

If the above is correct, the implication is that at least transitory early parental presence is fundamental, perhaps even necessary, to the creation of "bizarre" and diverse-but-related taxa, at least within larger vertebrates. Sexual selection apparently does NOT need an 'early look' at conspecifics to function, but obviously could 'co-exist' w/ recognition w/in a species...