system
Given the following post, respond as if you're commenting on Reddit:
human
Could an ancient Coelacanth breed with a modern Coelacanth ?

[I just picked coelacanth because I heard it is the oldest still surviving species (according to a source I have little faith in), and I understand they aren't 'unchanged', but just have a relatively stable body-plan.]

Basically, do we have any idea if an ancient individual from an enduring, relatively "unchanging" species, time-travelled to today, could breed with a modern version of that species?

Would all the millenia of genetic drift, etc prevent reproduction. And if it *would* prevent breeding, how does this affect our definition of 'species'? (Thats what got me thinking; the question of how well Linnaean Taxonomy reflects nature- but I guess I went off on a tangent.)
gpt
No, it could (probably) not.


The reason is that there is a bit of semantic confusion when we use terms such as "the coelacanth". Coelacanth refers to all lobe-finned fishes to ever have existed when used in the generic sense, and to the few surviving species within that group. Should you go back in time, the species of coelacanths you would encounter would not be the same which exist today, in the same way that you shouldn't expect to successfully breed a modern species of roach (Say *Blatta germanica* for arguments sake) with an extinct Cretaceous one (say, *Gondwablatta abrahami*). The cumulated genetic variation should normally exceed the ability to interbreed. Yes there are rare exceptions (ligers, mules, and like that), but as a rule interbreeding gets more and more unlikely the further removed 2 species are from one another, particularly animals (plants are a different matter).

There are currently 2 living species of coelacanth, *Latimeria chalumnae* & *Latimeria menadoensis*. They are the last remaining taxa of their subclass; both are highly endangered. To the best of our knowledge, these two species are not interfertile, although their geographic ranges do not overlap. Genetic caracterisation indicated they last shared a common ancestor about 30 to 40 million years ago.