Spinel Borewurm

As the borewurm's digging behavior broke up the substrate in Lamarck water table, food began to accumulate deeper in the soil. While the borewurm was more than capable of reaching this food, one population became optimized for this new environment, allowing them to dominate the deeper horizons of soil. This population would give rise to the spinel borewurm.

The spinel borewurm's namesake and main adaptation is its spinel exoskeleton. Unlike its ancestor, which excretes its Al3+ and Mg2+ as oxide wastes, the spinel borewurm directly incorporates them into its exoskeleton while omitting the Fe2+. The aluminum and magnesium are combined with the silicates gained from the basalt it consumes to form spinel. This change in exoskeleton formation has multiple effects. The first of which is an increase in exoskeleton hardness to a Mohs value of 8. The second and more important effect however, is an increase in useable Fe2+. This allows it to survive in low-oxygen environments like deep soils and anoxic waters. The spinel borewurm has also become smaller so that it requires less oxygen and food to survive. Spinel borewurms are not picky eaters. While they do consume the rhizoids of the cave flora growing in its environment, it will also burrow into and consume partially or fully buried carcasses and dead flora as well. Its sharp teeth help it tear through the flesh of the carcasses it burrows through They have a particular affinity for organisms containing large amounts of iron.