The skeletal remains of a marine

[Kierdale]

I intend to add a skeletal marine on one of my CSM vehicles as a trophy and while I'm not bothered that it probably should be bigger than a human skeleton (likely it will be missing an arm and at least some portions of both legs anyway) I did wonder about the black carapace.

Am I misremembering fluff that the carapace is basically (atop) the rib cage fused into one plate?

Or in other words should I use Green Stuff to smooth the skeleton rib cage flat and paint it black?

[The Unseen]

All marines ribs grow into each other into a hard solid sheath.

The explanation as to why this doesnt render them incapable of breathing I have no idea.

 

The black carapace is subcutaneous, but not bone mounted to my knowledge.

It goes in under the skin, connects with the nervous system, and has connector ports above the skin.

[Bryan Blaire]

From the August White Dwarf, Index Astartes: Rites of Initiation, The Creation of a Space Marine

 

Phase 19: Interface (The Black Carapace). This is the last and most distinctive implant. Black carapace looks like a film of black plastic when growing in the tanks. This is removed from its culture-solutoin and cut into sheets which are implanted directly beneath the skin of the Space Marine's torso. Within a few hours the tissue expands, hardens on the outside, and sends invasive neural bundles deep inside the Space Marine. After several months the carapace will have fully matured and the recipient is then fitted with neural sensors and transfusion points cut into the hardened carapace. These artificial plug-in points mesh with integral to the powered armor, such as the monitoring, medicinal and maintenance units. Without the benefit of a black carapace, a Space Marine's armor is relatively useless.

 

Per the same article, the ribs are not fused into a single plate, but rather an "extreme ossification of the chest cavity (caused by growth of the ribs forming a solid mass of interlaced bone plates)".

 

Sounds like from the most recent material, the bones expanded in the rib cage, but you'd still have seams, probably locations where the bones can slide past each other so that the natural flex of the torso is preserved. The Black Carapace sounds like it resides as a layer between the musculature and the skin, a secondary subdermal layer, so if the muscular layer is removed, the Black Carapace should have been removed as well.

 

By the by, the White Dwarf also describes when the Primaris organs are implanted as well , and they are interspersed with the standard Marine organs (the first two organs are implanted extremely early, in the 12-13 year old stage, just after the first few Astartes organs) - so it seems highly unlikely that Marines already created can be "upgraded" to Primaris. However, it doesn't completely preclude that there could be a process to allow such surgery to occur, however, there would be downtime for the new endocrine signals to begin to regulate properly and the new cellular mechanisms to stabilize.