DEFENSIVE ARMAMENT, ORGANS, AND BEHAVIORS OF FOSSIL MILLIPEDS

Defensive armament, organs, and behaviors of fossil millipeds can be deduced from preserved morphological features that are analogous to those of modern millipeds, and to behaviors frozen into the fossil record. Euphoberiidan millipeds in the Carboniferous genera Euphoberia and Myriacantherpestes, for example, bear both prominent dorsal and lateral spines, and a series of ozopores, repugnatorial pores. Even the largest known species of these genera, including Myriacantherpestes hystricosus and M. clarkorum, both armed with long spines, bear a complement of ozopores. Ozopores are also visible on various other fossil millipeds, ranging from Paleozoic forms to Cenozoic specimens preserved in amber. Repugnatorial material, or traces of that material, exuding from ozopores may be preserved in amber; a milliped specimen from the Dominican amber shows tubular gas chambers emanating from several ozopores.

Fossil milliped specimens typically represent outspread individuals or specimens in comma-shaped death positions. However, coiling and enrollment of various types, at least some of it defensive in nature, is sometimes preserved in the fossil record of millipeds. Adaptations facilitating enrollment can also be seen in some specimens of fossil oniscomorphs (pill millipeds). Some specimens of spinous fossil oniscomorphs from Europe and North America are preserved in partially coiled positions, and have roughly similar morphology to that of extant oniscomorphs which coil into a tight ball. Nonspinous fossil oniscomorphs also have morphological features that would have facilitated coiling. These include pleurite configuration and details of the shield, the enlarged second segment.

At least some partial specimens of fossil millipeds may represent parts of dismembered carcases. Specimens lacking heads, and specimens consisting only of heads, are examples. Fossil millipeds are sometimes found in coprolites, usually along with other organisms or finely comminuted material. These coprolites were likely to have been generated by opportunistic predators. In some cases milliped carcases were scavenged after being buried.