Bristly Millipedes
Polyxenida
Classification
- Phylum: Arthropoda
- Subphylum: Myriapoda
- Class: Diplopoda
- Order: Polyxenida
Pronunciation
How to pronounce Polyxenida: /pɒlɪksəˈniːdə/
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Summary
Polyxenida, commonly known as bristly or pincushion millipedes, is an order of small millipedes characterized by their soft bodies adorned with tufts of bristles. They have a unique reproductive strategy and are primarily found in detritus-rich environments, providing essential ecological services.
Physical Characteristics
Soft-bodied, non-calcified body, typically 1.5 to 4 mm long, with distinctive tufts of bristles (setae). Some species have fewer than 17 leg pairs and lack copulatory appendages in males.
Identification Tips
Polyxenidae usually have ocelli, the 8th antennomere shorter than the 7th; Lophoproctidae lack ocelli, with the 8th antennomere subequal or longer than the 7th.
Habitat
Worldwide; found commonly in humus-rich soils.
Distribution
In the New World, from southern Canada to Brazil; Polyxenidae occurs across much of the US, while Lophoproctidae is recorded in the Florida Keys and possibly southern Texas.
Diet
Detritivorous, feeding on decaying organic matter.
Life Cycle
Polyxenida undergo a process known as hemianamorphosis, where they grow by molting and adding segments and legs until reaching a fixed adult form.
Reproduction
Males deposit spermatophores into webs constructed by them, which are then picked up by females. Some species reproduce asexually through parthenogenesis.
Predators
Predatory insects, particularly those whose limbs and mouthparts can become entangled in their bristles.
Ecosystem Role
Play a role in nutrient cycling and soil health by feeding on decomposing materials.
Collecting Methods
- Sifting leaf litter
- Hand collecting
Preservation Methods
- Ethanol preservation
- Drying
Evolution
Polyxenida is the only living order of the subclass Penicillata, which is basal to all other millipedes in the subclass Chilognatha.
Similar Taxa
- Chilognatha
- Penicillata
- Polydesmida
Misconceptions
Often confused with other millipede orders due to their soft bodies and small size; lack of chemical defenses may lead to misconceptions about their vulnerability.
Tags
- millipede
- Polyxenida
- biodiversity
- soil health