| Feather-winged beetles | |
|---|---|
| Ptenidium pusillum from Die Käfer des Deutschen Reiches vol. 2 (1908) | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Hexapoda |
| Class: | Insecta |
| Subclass: | Pterygota |
| Infraclass: | Neoptera |
| Superorder: | Endopterygota |
| Order: | Coleoptera |
| Suborder: | Polyphaga |
| Infraorder: | Staphyliniformia |
| Superfamily: | Staphylinoidea |
| Family: | Ptiliidae Heer, 1843 |
| Subfamilies | |
|
5, see text |
|
| Synonyms | |
|
Trichopterygidae Erichson, 1845 |
|
Ptiliidae is a family of very tiny beetles with a worldwide distribution. This family contains the smallest of all beetles, with a length of 0.5 mm, and even the largest members of the family do not exceed 2 mm. The weight is approximately 0.4 milligrams.[1]
They are colloquially called feather-winged beetles, as the hindwings are narrow and feather-like. The obsolete name Trichopterygidae literally means "the hair-winged ones".
There are some 630 described species in about 85 genera, but large numbers of specimens in collections await description and the true number of species is clearly much higher than this. The Ptiliidae are divided into 5 subfamilies:
The Ptiliinae is the largest of these; over half of the described genera belong there.
Adults and larvae are usually found in rotting organic material in a wide range of habitats. The eggs are very large in comparison to the adult female (maybe half the length) so only one egg at a time can be developed and laid. Parthenogenesis is exhibited by several species.
Fossil ptiliids have been recorded from the Oligocene, roughly 30 million years ago. Some subfossil specimens are also known from the Holocene, but such remains are usually from species that still exist today.