Renaldo thinks that one crab is sexy at least

I couldn't finish the first book. :(( Ironically, I liked how he finished Wheel of Time. I DK. It's not terribly written; it just didn't stick. Robert Jordan was a far worse writer lol.

Cytoverse too

Oh yeah, that crab could definitely get it

Land octopi would be pretty cool though.

Tech needs electricity and fire is not universal. That is what we use.

Our brain is lot more complicated and efficient than the computers we make and it uses ions, in liquid media. So something that lives in water could definitely be able to make something that would be able to use similar things to do processing. Water is also really good with doing things, it's flexible but doesn't compress/expand like air does. Think about hydraulic systems. You can make them smaller and smaller as your tech progresses. Mechanical things using metals and such would work in water as well. Think about gold and such that can be used for electricity as well, we don't use it because it's valuable, but an alien world could have abundance of gold for them to use.

They must have limbs skilled enough to handle and construct this technology, a complex communication system, and a binocular vision system (for this reason the most used in all species) to perceive their environment. The humanoid shape is one that best fits these maxims and therefore it is quite possible that an advanced species would also have a more or less similar shape.

Elephants meet all of these criteria as well. A complex limb (their trunk), a complex communication, and binocular vision (although I don't see why this is necessary).

I can't help but notice that you didn't list a whole lot of traits that would be considered vital to having a fairly human sillhouette. There's nothing here about obligate bipedalism, for example, or having just two legs in the lower part of the body at all. There's nothing here about how the forelimbs are articulated, and whether it would look meaningfully like hands or an array of dexterous tendrils or something. And all this gritty realist speculative biology seems out of place when most sci-fi is basically a particular sub-genre of fantasy anyway. Even being generous to the sci-fi writers, supposing the universe works in a fundamentally different way from how ours does (breaking laws of relativity and entropy, commonly), why can't some ecosystems work out to stretch your imagination of what could be an advanced species? It all seems very narrowly prescriptivist, even beyond the fact that this is fiction to the point of taking negative liberties with the bounds of what is truly realistic.

Edit: idk, it just seems obtuse. Like, "Advanced life can only be carbon-based because being that way affords these benefits" without considering that other models could provide other benefits (I'm sure you know better than I about the use of silicon-based life in speculative biology). And that's if the subject is addressed at all.

Genets are bad example, because Viverridae are the closest relatives to Felidae. Convergent evolution would be better illustrated by fish and dolphins.

known species with a human level of higher intelligence

• Humans (allegedly; evidence points to most being dumb as a rock).
• Some species of extinct hominids (sure, but they're extinct).
• Dolphins (and orcas, which are big fancy dolphins); absolute creeps, though.
• Whales, possibly, though they tend to keep to themselves, so who knows.
• Some species of octopods.
• Some species of parrots.
• Some species of corvids.
• I swear some of those black and white sheepdogs seem more intelligent than many of the people I know.

Taken more seriously, having the evolutionary background to have:

• fine control over your limbs, like fingers
• 3D-thinking (throwing) and manipulation
• cooperation

another human-like civilization is pretty unlikely.

I've never seen a crab measure thousandths of an inch, or back a Phillip's head screw out of a hole with their crab strength. Tools are still required.

(V) OwO (V) What's this? snip snip

Taste like crab, talk like people.

Sure, but have you ever tried to disarm a crab and lived to tell the tale?