Periodical cicadas are the only confirmed periodical animals with long life cycles. In Japan, however, 8-year periodicity had been suggested in a species of train millipedes that had frequently obstructed trains in the central mountainous region of Honshu, Japan. This species was identified as Parafontaria laminata armigera Verhoeff (Diplopoda: Xystodesmidae), which is endemic to Japan. We finally confirmed the 8-year periodicity of this millipede using detailed surveys of life histories over 8 years. Seven broods were recognized, with almost no overlaps in their distributions. We also report the historical outbreaks and train obstructions of this millipede during 1920–2016. This is the first confirmed case of periodical non-insect arthropods.

周期性蝉是唯一被确认具有较长生命周期的周期性动物。然而，在日本，有人提出一种8年周期的火车千足虫经常在日本本州中部山区阻塞火车。这个物种被认定为Parafontaria laminata棉铃虫费尔赫夫（倍足纲：Xystodesmidae），这是特有的日本。我们通过详细调查了8年的生命历史，最终确定了这种千足虫的8年周期。确认了七个育雏，它们的分布几乎没有重叠。我们还报告了1920–2016年该千足虫的历史暴发和火车阻塞情况。这是首次证实的周期性非昆虫节肢动物病例。