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Staphylinoidea

Staphylinoidea is a superfamily of beetles. It is a very large and diverse group with worldwide distribution.

Description

Adult staphylinoids are generally small beetles no more than a few millimetres long, though Staphylinidae can reach 50 mm long and Silphidae can reach 45 mm. The superfamily includes the smallest beetles (and the smallest of all non-parasitic insects) in family Ptiliidae. Most Ptiliidae do not exceed 1 mm long as adults, while the smallest species is just 325 μm long.

Adults can be recognised by the hind wings having no accessory posterior ridge (locking device), no medial loop, no wedge cell and no apical hinge. The 8th segment of the abdomen is not entirely invaginated within the 7th. The head usually lacks a coronal suture (rarely with a short, rudimentary suture).

Larval staphylinoids have 3-segmented (rarely 4-segmented) maxillary palps with distinct (often fused) galia and lacinia. The body usually has well-developed tergites and sternites. The spiracles are annular or annular-biforous. There are no epistomal lobes.

Systematics and evolution

Staphylinoidea contains the following subgroups:

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

Phylogeny

A 2019 molecular phylogenetic study confirmed the monophyly of Ptilidae and found that it is sister group to Hydraenidae.

References