What is unique or rare about the VM Zodiac signs?

[Mark Knowles]

Scorpio
Both animals have 4 for legs and a long tail thougn the left image's legs are shorter or the animal is crouched. 
The left image has lines and points drawn in its back, the VMS seems to have some points too and maybe some lines but the resolution 
on the image is low and I cant see the details.

What is the green animal meant to be?

A Scorpion?

Or something else?

I doesn't look much like a scorpion, but maybe that was just how they represented it at the time.

I have seen other examples of this green creature.