Hydroscapha natans

The subordination Myxophaga with only four families the smallest suborder of beetles ( Coleoptera). It was described in 1955 by Roy Crowson, making it the youngest suborder of beetles. The taxonomic position of the Group is well justified by its monophyly and its sister relationship to the Polyphaga. Fossil evidence of subordination are not known.

  • 4.1 Notes and references
  • 4.2 Literature



The beetles are very small and can reach a maximum body length of 2.7 mm, with most species are even considerably smaller. The Autapomorphieen the Myxophaga include the absence of Galea, the presence of a movable tooth on the left mandible, the very broad connection between the Ventriten of meso-and metathorax and the fringed posterior border of the hind wings. Other features of subordination are the more or less club-shaped thickened sensors that have less than nine members generally, the presence of the Mola ( Kaurand ) to the mandibles and the exposed pleura of the prothorax. The Notopleuralnaht of the prothorax is formed, the Ventrit is very short, the indentations to accommodate the hips ( coxae ) on mesothorax laterally open and limited in most species by the Mesepimeron and Metanepisternum and the hind wings are curled to rest on the top. The muscles of the thorax is modified in comparison to the Adephaga and especially Archostemata. A number of muscles of the three thoracic segments are modified or missing.


Only the larvae of Lepiceridae are so far unknown. The larvae are adapted to an aquatic lifestyle. The jaws are strongly developed in the Torridincolidae and greatly extended. The species of most genera of this family have long hair at your sides. Respiration takes place through unique within the order of the beetles tracheal gills. The larvae of Hydroscaphidae and Torridincolidae have a broad and highly flattened body. Furthermore, in the larvae of all the families of the head is widened and provided the body with scale-like, serrated appendages. The sensors are bipartite.

Way of life

Both imagines and larvae of all species feed exclusively or mainly of algae and cyanobacteria. Most types of Torridincolidae and Hydroscaphidae live in different aquatic habitats. The remaining two families whose lifestyle is poorly researched, colonize moist substrates, especially on river banks. Pupation takes place within the exuvia of the last larval stage.

Taxonomy and systematics

The cladistic analysis of imagines and larvae showed a sister group relationship between the Hydroscaphidae and the spider beetles ( Sphaeriusidae ) that form the sister taxon of Torridincolidae together. The Lepiceridae are the other three families in a sister group relationship. Thus, there are the following relationships:

Lepiceridae Hinton, 1936

Torridincolidae Steffan, 1964

Hydroscaphidae Leconte, 1874

Ball beetle ( Sphaeriusidae Erichson, 1845)