After a quick scan through that thread and some of the earlier arguments here...
I think there may be just a few key assumptions that, if removed, already present plausible explanations for the inhabitants as represented in game.
Crucially, I don't think the first one has been discussed beyond a cursory level.
1 - Taxonomic
Is a red lobster the same species as a green lobster?
Are they even lobsters?
Are classifications concerned with evolution/genetic similarity or could they instead be based on more practical considerations for the average spacefarer?
Just as a young child might consider a dolphin a fish or a spider an insect, taxonomy isn't always as obvious as we might think. In the far future of space-traders travelling from system to system (potentially without ever landing on a planet) what use is the knowledge of the inhabitants?
In addition, it is not unheard of for species to be reclassified as human understanding of evolutionary pathways develops. So reclassifying groups is nothing new.
You said I would be trading with mammals, damn it!
They had fins!
Yes, mammals with fins.
Mammals don't have fins and live in the %@$#ING OCEAN!
Fish, fish have fins!
If I'd known I'd have been trading with fish then I wouldn't have brought them 35 tons of %@$#ING BANANAS!.
... Er, mammals can have fins too.
I'm a trader not a scientist! When you tell me mammal it means a monkey. You got that? A %@$#ING MONKEY! ... a monkey or a dog...
So, if classification were to be more practical from a future spacefaring humanocentric point of view, how might it work?
One possible reading (with practical considerations for species interactions):
- Bird = can fly
- Feline = solitary carnivore
- Frog = can leap
- Humanoid = miscellaneous
- Insects = group behaviours
- Lizards = heat sensitive
- Lobster = semi aquatic
- Rodent = contagion risk
In which case could a bat then be classed as a 'furry bird'? If so we now have explanations for some very strange (and sometimes seemingly contrary) descriptions of inhabitants.
In game evidence:
Slimy Lobsters (newts?), Bony Birds (beetles?), Bony Felines (praying mantids?), Furry Insects (lions?)
Whilst the above examples are deliberately provocative, I think they illustrate how different a classification system could be.
Human colonials are by far the most common group, suggesting a humanocentric classification system
Inhabitants is listed as one of the key factors on the F7 screen, suggesting a level of importance given that the trader need only dock at a station and not land on the planet.
2 - Generative
Need there be a common point of origin for all 'lobsters'?
This relates to taxonomic assumptions.
One reason why there might not: they're classification as lobsters need not be based on a common origin but rather the independent invention/evolution of common traits. For example, aquatic mammals swim in superficially similar manner to fish yet the development of their swimming style was (for the most part) independant. We only have our own planet's evidence for this but then if we're talking about life then that very much describes the boat that we are in.
In game evidence:
there are no obvious central points for any 'animal' group in a statistical sense
3 - Interactive
Why might all lobsters group together?
Shouldn't there be areas of conqured space, much like there are for human colonials?
Development / availability of hyperspace technology has already been discussed but what about the idea that suitable planet types might simply be less common? The planet that a 'lobster' species might regard as habitable might be much less common than one that is suitable for a human. As for lobsters on Earth and their being able to colonise similar planets, I refer you to taxonomic assumptions above.
In game evidence:
there are no obvious 'clusters' of inhabitant types beyond those that one might expect to occur randomly
The above is only one possible interpretation of the in game situation regarding planetary inhabitants and by no means do I claim it to be 'correct'.
Where I think it may be useful however is to illustrate how easily assumptions can 'get in the way' of making sense of fictional environments rather than simply accepting them and having fun with an evocative, identifiable and yet extremely brief description of alien life-forms.
Besides, space lobsters are cool