Bristle-millipede
Guides
Polyxenida
bristle millipedes, bristly millipedes, pincushion millipedes
Polyxenida is an order of millipedes distinguished by a soft, non-calcified exoskeleton covered in distinctive tufts of bristles. They are the only living members of the subclass Penicillata, which represents the most basal lineage of living millipedes. This order comprises approximately 148 species across four families worldwide. Polyxenida exhibit several unique derived traits including indirect sperm transfer via spermatophores deposited in webs, and a mechanical defense using detachable barbed bristles rather than chemical defenses.
Polyxenus
Polyxenus is a genus of bristly millipedes in the order Polyxenida, the sole extant genus of the family Polyxenidae. These small millipedes are characterized by their distinctive tufts of setae (bristles) and are notable for being among the most morphologically derived millipedes, having lost many ancestral diplopod traits. The genus contains at least 30 valid species and has a broad geographic distribution across multiple continents. Polyxenus species are frequently found in association with ants, serving as either symbionts or specialized prey.