Drotops armatus trilobites from Morocco, the double specimen trilobite plate enables a glimpse back into the Devonian period of what is now North Africa. The armatus thoracic segments have been engineered by evolution to interlock and provide flexibility and defence, under this chitin exoskeleton the arthropod defended its soft body parts now lost to the ravages of the fossil bed. In this specimen the tubercles seen on the carapace or exoskeleton have no spines attached. The Drotops evolved spines giving the invertebrate more defense perhaps? We do not know positively. On differing varieties scientist theorise spines could also be for a sensory defence or foraging aid. Intriguingly, we have so much to learn from these alien to us know bugs from prehistory.
The arthropod's have three full body or carapace length lobes longitudinally. These name it, from the Greek, tri - lobite, the lobes run into the pygidium (tail), the pygidium is one of the other three parts of the exoskeleton or carapace, which are often found separated in the fossil beds. These run across the carapace left to right and are the glabella (head), thorax (mid body section) and pygidium. These make up the complete carapace or exoskeleton, this is shed in the animal’s lifetime. We find carapaces enrolled which could possibly have been a defence posture or the shed carapace.
Fewer complete specimens are unearthed from fossil sites of Morocco generally and in the heyday of discoveries and collecting. Exhausted beds become more difficult to manage over time as fossil material is excavated from deeper deposits. There are many other factors which influence the outcome of fossils collecting in Morocco generally. Once collecting specimen of good quality was a relatively successful process, available across several Moroccan trilobite species, we now find less quality specimens available. Many older established beds suffer erosion, more frequent flooding, increasingly dwindling supply of decent specimens in the bedding plane, and deeper veins of sedimentary fossilerous limestone contribute particularly to the large Phacops types becoming more scarce as the work of extraction becomes more arduous.