Erotylidae

These beetles are typically smallish (less than 1 cm long) as adults, and have a more or less oval "pill-shaped" form; some genera are elongated, some are more rounded. Their antennae are rather large compared to their overall size, and usually prominently expanded at the tip. The usual coloration of pleasing fungus beetles is either black (often with a few jagged bands across or large spots on the elytra in a contrasting reddish-ochre to yellowish color), tan to chestnut brown (often with numerous small black dots on the upperside), or part black part brown without pattern. While most genera have a shiny surface – occasionally with metallic iridescence –, some are hairy.

Erotylidae feed on plant and fungal matter; some are important pollinators (e.g. of the ancient cycads), while a few have gained notoriety as pests of some significance. Sometimes, useful and harmful species are found in one genus, e.g. Pharaxonotha. Most pleasing fungus beetles, however, are inoffensive animals of little significance to humans.

Pleasing fungus beetles are an ancient lineage, probably originating considerably more than 100 million years ago. The oldest fossil assigned to this group is an undescribed species known from Early Cretaceous (Barremian) Lebanese amber.^[2]

The division into subfamilies and tribes is not definitely established. For example, the Cryptophilinae, Loberinae and Pharaxonothinae are sometimes included as tribes in the Xenoscelinae, and similarly the Dacninae, Encaustinae, Megalodacninae and Tritominae in the Erotylinae, resulting in a 3-subfamily arrangement. The lasting doubts on the monophyly of lower ranked taxa within Erotylidae necessitate further phylogenetic studies with better sampling and studies of unexplored character sets, for example the metendosternite and penile flagellum, which are generally lacking detailed morphological studies within the Coleoptera literature.^[3]

The Erotylina taxonomy, as revised by Pecci-Maddalena in 2021, is based on traits such as their different colors and not on morphological differences like mouthparts, thorax, and abdominal terminalia.^[4]