“My aim was simply to point out that evolution can favor the continuances of genetic sameness where environmental influences remain in stasis.”
The mistake I made here that you may be hung up on is using the words ‘genetic sameness’ when I should have used morphological sameness. In the first place you have chosen to emphasize morphological differences in various coelacanth types to bolster the notion of genetic diversity, while I have tried to tie the similarities among coelacanth groups to indicate a genetic similarity.
This raises a debated issue among evolutionists. Paleontologists differentiate species based on morphological differences whereas among living organisms species are defined by whether individuals can breed successfully.
So you used a wildly unsubstantiated myth to point that out? And you think environmental stasis occurred continuously over the course of at least 400 million years? And you think that a paucity of fossils can determine the true age of the Actinistia order?
So for the reasons that genetic and morphological differences may not be perfectly analogous, I chose to stress the fact that the morphological change in coelacanths over the known appearance in the fossil record at least 400 million years would imply less genetic differences between ancient and modern examples than between the youngest common ancestor between us and them.
I assume then that the lack of the degree of morphological differences we see in coelacanths modern and ancient compared say to the morphological differences in us and them suggest a greater degree of stasis of environment they have faced compared to us.
Greater stasis does not require perfect stasis. So, this would imply that genetic drift would be a far larger cause of gene differences among coelacanths than change caused by adaption caused by environmental factors. Less change in the environment, less adaptive pressures.
None of this would have to do with how many fossils are known.
My contention then is that the greater the evidence that a lineage can be recognized over vast periods of time, the more likely the genetic material of ancient members to modern ones is likely to be compared to the genetic material of members of groups who must also have ancient relatives to that ancient lineage in question but have only recently differentiated themselves as a distinct group.
The myth that coelacanths living coelacanths are genetically identical to ancient ones is a myth, but the assumption that the retention of morphological similarities to define a lineage over long periods of time implies a greater retention of genetic similarities than for groups with short histories I think is sound.
Don’t fix what ain’t broke.