甲螨亚目（Oribatida），又名隐气门亚目（Cryptostigmata）， 是蛛形纲蜱螨亚纲螨形总目恙螨目之下的四个亚目之一，以青苔或甲虫为食。亦有其他文献把本分类归为目级，学名不变。牠们的大小从0.2至1.4毫米。

甲螨的新陈代谢速率一般比较低，发展也慢，繁殖力也低。 Species are iteroparous with adults living a relatively long time; for example, estimates of development time from egg to adult vary from several months to two years in temperate forest soils. Oribatid mites have six active instars: prelarva, larva, 3 nymphal instars and the adult. All these stages after the prelarva feed on a wide variety of material including living and dead plant and fungal material, lichens and carrion; some are predatory, but none is parasitic and feeding habits may differ between immatures and adults of the same species.

Oribatida (formerly Cryptostigmata), also known as moss mites or beetle mites, are an order of mites, in the "chewing Acariformes" clade Sarcoptiformes. They range in size from 0.2 to 1.4 millimetres (0.008 to 0.055 in).

Oribatid mites generally have low metabolic rates, slow development and low fecundity. Species are iteroparous with adults living a relatively long time; for example, estimates of development time from egg to adult vary from several months to two years in temperate forest soils. Oribatid mites have six active instars: prelarva, larva, 3 nymphal instars and the adult. All these stages after the prelarva feed on a wide variety of material including living and dead plant and fungal material, lichens and carrion; some are predatory, but none is parasitic and feeding habits may differ between immatures and adults of the same species.