Polyxenus lagurus

Bristly Millipede

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Family: Polyxenidae · Class: Diplopoda · Order: Polyxenida

Polyxenus lagurus (Bristly Millipede) is a California animal in the Polyxenidae family.

The bristly millipede (Polyxenus lagurus) is a diminutive arthropod measuring approximately 2 millimeters in length, making it one of the smallest millipedes in North America. This species belongs to the order Polyxenida and is distinguished by its distinctive bristly appearance, earning it alternative common names including fuzzy millipede and pincushion millipede (BugGuide). Unlike typical millipedes, P. lagurus possesses a soft, flexible body covered in characteristic bristles or setae that give it a fuzzy texture. The body is typically pale to light brown in coloration with 13 body segments, each bearing a single pair of legs rather than the two pairs found in most other millipede orders. Polyxenus lagurus has a broad distribution across North America, with documented occurrences spanning from the eastern United States westward. According to BugGuide, the species has been recorded from Maryland to Texas and northward to Illinois, though its full range likely extends beyond these documented localities. The species appears to have a cosmopolitan distribution pattern, possibly aided by human transport activities. This millipede inhabits a variety of microhabitats, typically favoring moist environments with abundant organic matter. The species is commonly found under bark, in leaf litter, beneath stones, and in soil rich in decomposing plant material. Unlike many millipede species that prefer deeper soil layers, P. lagurus tends to occupy surface habitats and shallow soil environments where humidity levels remain relatively stable. Bristly millipedes are detritivores, feeding primarily on decaying organic matter, fungi, and microorganisms found in their leaf litter and soil habitats. Their feeding behavior contributes to nutrient cycling and soil formation processes. The species exhibits typical millipede defensive behavior, curling into a tight coil when threatened. Reproduction involves direct development without a larval stage, with young millipedes resembling miniature adults but possessing fewer body segments. Juveniles molt several times as they mature, adding additional segments and leg pairs with each molt until reaching the adult complement of 13 segments. Polyxenus lagurus does not possess any federal or state conservation listing status and appears to maintain stable populations across its range. However, the species was included on Arkansas's 2006 Species of Greatest Conservation Need list, not due to immediate conservation concerns but because insufficient information exists regarding its taxonomic status, life history, and population trends (BugGuide). This designation reflects the general lack of comprehensive research on small soil arthropods rather than evidence of population decline. The species faces typical threats associated with habitat modification, including soil compaction, pesticide use, and removal of leaf litter and organic matter from natural areas. Climate change may also influence soil moisture regimes that are critical for millipede survival. Despite these potential pressures, the species' broad distribution and apparent adaptability to various microhabitat conditions suggest it remains relatively secure across most of its range.

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, and more.