Everybody pokes fun at Cardassians having some more mammalian characteristics claiming “scientific inaccuracy” because they’re shown to be mostly reptilian, but tbh? We would absolutely run into this sort of thing if astrobiology ever got to organisms that complex because phylogeny (and kind of biology as a whole tbh but let’s not get into all that) is ✨ Kind Of A Mess ✨
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Can you imagine the federation science conference after first contact with Cardassians where they’re all just scrambling to classify these as something
“So. What’s up with that?” “……..scales. Reptile.” “But hair, yes?” “Yes hair” “body heat?” “Maybe? Not very efficient, if they do” “how do they.. How do they reproduce. Egg?” “We don’t know” “what do you mean we don’t know” “hey do they produce milk” “we don’t know that either” “what do you mean we don’t kn-”
Someone proposes they might be birds and someone else argues that birds are reptiles and now they’re getting into a fistfight
Phylogenetic taxonomy is meant to reflect evolutionary history. I would argue that no alien species should be classified as a bird, mammal, etc., because their mammalian (or reptilian or whatever) characteristics are the result of convergent evolution, not common ancestry with species on Earth. Lumping them together is just bad cladistics.
The reason ‘reptile’ is a problematic grouping here on Earth is because it’s paraphyletic unless you include birds (and arguably mammals). Fun fact: crocodilians are more closely related to birds than they are to turtles or lizards. (See here or here for more info.) Ideally, a taxonomic grouping (a clade) should be monophyletic, meaning that it includes all the descendants of a common ancestor. A group that includes the common ancestor but only some of the descendants is paraphyletic.
A group like ‘Humanoids’ in the ST universe may have some utility as a category describing species with similar physical characteristics (more akin to old-school Linnaean taxonomy), but it would not work as a taxonomic classification in a phylogenetic system. That would be an example of a polyphyletic group (i.e., a group derived from separate evolutionary lineages that does not include a shared common ancestor).
I mean, I’m oversimplifying a bit here because I’m spouting this off on Tumblr on the fly and also because in practice taxonomy is a hot mess that just gets messier the more genomes we sequence and fossils we uncover. But this is already getting tl;dr so.
Really, I doubt any biologist in the Star Trek universe would be surprised that alien organisms don’t share exactly the same suites of characteristics found in similar looking Earth organisms, because they would have completely different evolutionary histories.
(Although that also presumes that anything about ST biology makes sense, which, well…)
I’ve always theorized that Cardassians fall somewhere between reptiles and mammals, for the purposes of human classification systems. I refer to them as turn’Hu - “Warm Scale.”
