A common recurring design I see in creatures are ones that have two front legs but no hind legs, such as the lindwurm in mythology and more recent examples being the skullcrawlers from the monsterverse and the dawdlers from the korean movie dragon wars.
How would such a bodyplan realistically work tho? Aren't hind legs normally what support the weight of a land animal? And what evolutionary pressures would cause a terrestrial tetrapod to lose its back legs but retain its front ones? How would forelimbs specialize to carry more of the weight, especially if there is still the weight of the lower torso and abdomen behind it, plus a tail? Would it be able to assume a theropod-esque posture or would the rear part inevitably drag on the ground like the aforementioned dawdlers and skullcrawlers?
Well I actually have a real world answer for this!
Behold the mole lizard:
(Image description: photo of a pink worm-like lizard with only front legs and no back legs on its very long body. End description)
And the article i got this image from:
Image from here. The Mexican mole lizard (Bipes biporus), commonly known as the five-toed worm lizard, or simply as Bipes, is a species of a
I would also point to marine mammals like seals and whales, whose front limbs have become flippers and whose back limbs have become smaller or totally vanished.
When it comes to balance, the front legs at least can keep the head up, while becoming a fully upright creature with no front limbs requires much different balance. Now, there have been dinosaurs and flightless birds that went for the back-legs-only body plan. The kiwi, for example. So both options are viable for different reasons!
You'll notice that for the creatures who kept their front limbs, those limbs have gained a specialized purpose. Swimming or digging, in the examples I gave. For the dinosaurs and birds that have kept strong back legs and nearly lost their front limbs, running is a priority and they use their mouths to grab everything.
So it really depends on the forms of locomotion and feeding that the creatures prioritize. The lindwurm is more familiar to me, and such a long body that remains low to the ground really would benefit more from the pulling locomotion of front limbs than it would benefit from load-bearing back legs.
Having a body that drags on the ground is not inferior to other forms of locomotion! It is simply a different way to move, which comes with different priorities and is better adapted for specific environments like water or burrows.
Why, snakes have gotten rid of their limbs altogether, and they're doing fine! It's a mistake to assume that any one type of body plan is inherently superior to others. They all have their benefits and downsides.
