They could be ship components (antennae/heat radiators/technobabblon particle emitters) painted and decorated to look like spines, etc., as a purely aesthetic design choice.
These guys aren't humans, so just because we wouldn't decorate our ships to look like skin and nails doesn't mean they wouldn't.
Also, they've been through some unpleasant interaction with other alien species, if I remember the Dregh back-story right. It might be a matter of pride -- maybe they really *do* want us to think "oh here come those ferocious cold-blooded lizardy aliens! Curse them and their egg-hatched young!" when we see their ship, as a matter of pride for them as a species. Based on their backstory, they probably rely on physical strength more than humans do, and perhaps still think of themselves a bit as wild hunters -- so perhaps for them it makes more sense to decorate their ships to look like natural predators, or like symbols of their own bodies' physical power.
Besides, humans
have decorated vessels in all sorts of weird ways throughout history. Figureheads on sailing ships? (Ships with boobs indeed... >_<) Viking ships with bows carved to look like dragons? Ancient Greek ships with
eyes?
Also, there is really no way in heck Allegiance can be hard science fiction. Faster-than-light travel, super-dense asteroid fields... Really, best to just accept that the game is set in a good old-fashioned Space Opera, and make it a good one.
(Doesn't mean you can't try to justify everything with technobabble, though...
)
"South of the Alps and East of the Adriatic, paranoia is considered mental equilibrium..."
Omnia Mutantur, Nihil Interit.
