隐翅虫下目

特征

大多数隐翅虫下目的甲虫体型属小型至中等。这个多样化的类群几乎没有明显的衍征。其具有原始的11节触角，以及位于双眼后方明显收窄的颈部。前胸背板具有轮廓分明且宽大的侧缘。幼虫的腿具5节，第10腹节常具或细或粗的棘刺或钩状结构。尾钩（幼虫及蛹腹部后端的一对“角”状结构）具基部关节。

分类学与演化

隐翅虫下目隶属于多食亚目，通常被归类为下目或系列等级。该下目包含三个总科：

阎甲总科 Histeroidea，包括阎甲科。

牙虫总科 Hydrophiloidea，包括牙虫科。

隐翅虫总科 Staphylinoidea，包括苔甲亚科、葬甲亚科及隐翅虫科。

一些近期研究亦将金龟子总科（隶属金龟子下目）纳入其中，共同构成所谓的牙虫谱系（Hydrophiloid lineage）。牙虫总科与阎甲总科之间存在姐妹群关系，此观点获得强力支持。

明确的化石纪录可追溯至三叠纪，该下目很可能起源于中生代早期。

Staphyliniformia is a large infraorder of beetles. It contains over 70,000 described species from all regions of the world. Most species occur in moist habitats - various kinds of rotting plant debris, fungi, dung, carrion, many live in fresh water.

Characteristics

Most Staphyliniforms are small to average sized beetles. The diverse group has few clear apomorphies. They have primitively 11-segmented antennae, a constricted neck well behind the eyes. The pronotum has a well defined, large lateral edge. Larval legs are 5-segmented, the 10th abdominal segment is often with more-or-less fine or strong spines or hooks. Urogomphi (paired "horns" at posterior tip of abdomen of larvae and pupae) with basal articulation.

Systematics and evolution

Staphyliniformia belongs to the suborder Polyphaga and is usually given an infraorder or series rank. It contains three superfamilies:

Histeroidea, including the clown beetles.

Hydrophiloidea, including the water scavenger beetles

Staphylinoidea, including antlike stone beetles, carrion beetles, and rove beetles.

Some recent studies also include the superfamily Scarabaeoidea (infraorder Scarabaeiformia), forming together the so-called Hydrophiloid lineage. A sister group relationship of Hydrophiloidea and Histeroidea is strongly supported.

The unambiguous fossil record dates back to Triassic, and an early Mesozoic origin of the group is probable.