Myxophaga
| Myxophaga | ||||||||||||
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| Scientific name | ||||||||||||
| Myxophaga | ||||||||||||
| Crowson , 1955 |
The suborder Myxophaga is the smallest suborder of the beetles (Coleoptera) with only four families . It was described by Roy Crowson in 1955 , making it the youngest suborder of the beetles. The taxonomic position of the group is well established by its monophyly and its sisterhood to Polyphaga . Fossil evidence of subordination is not known.
features
Adults
The beetles are very small and reach a maximum body length of 2.7 millimeters, with most species even being significantly smaller. The autapomorphies of the Myxophaga include the absence of the galea , the presence of a movable tooth on the left mandible , the very broad junction between the ventrites of the meso- and metathorax and the fringed posterior margin of the hind wings. Further features of the subordination are the more or less club-shaped thickened antennae , which as a rule have fewer than nine limbs, the presence of the mola (chewing edge) on the mandibles and the exposed pleura of the prothorax . The notopleural suture of the prothorax is formed, the ventrit is very short, the indentations to accommodate the hips ( coxes ) on the mesothorax are open on the sides and in most species are delimited by the mes epimeron and the met anepisternum and the hind wings are at rest at the tip curled up. The muscles of the thorax are modified compared to the Adephaga and especially the Archostemata . A number of muscles in the three thoracic sections are modified or absent.
Larvae
Only the larvae of the Lepiceridae are still unknown. The larvae are adapted to an aquatic way of life. The claws of the Torridincolidae are strong and very elongated. Most species in this family have long hair on the side of their bodies. Breathing occurs through tracheal gills that are unique within the beetle order. The larvae of the Hydroscaphidae and Torridincolidae have a broad and strongly flattened body. Furthermore, the head of the larvae of all families is widened and the body is provided with scale-like, toothed appendages. The feelers are twofold.
Way of life
Both the adults and the larvae of all species feed exclusively or predominantly on algae and blue-green algae . Most species of the Torridincolidae and Hydroscaphidae live in different aquatic habitats. The other two families, whose way of life has been poorly researched, colonize moist substrates, especially on river banks. Pupation occurs within the exuvia of the last larval stage.
Taxonomy and systematics
The cladistic investigation of adults and larvae revealed a sister group relationship between the Hydroscaphidae and the ball beetles (Sphaeriusidae), which together form the sister taxon of the Torridincolidae. The Lepiceridae are in a sister group relationship with the other three families. The following relationships result:
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supporting documents
Individual evidence
- ↑ a b c d Rolf G. Beutel, Richard AB Leschen: Handbuch der Zoologie - Coleoptera, Beetles, Volume 1: Morphology and Systematics (Archostemata, Adephaga, Myxophaga, Polyphaga partim) . 1st edition. de Gruyter , 2005, ISBN 3-11-017130-9 , p. 43 f . (English).
literature
- Rolf G. Beutel, Richard AB Leschen: Handbuch der Zoologie - Coleoptera, Beetles, Volume 1: Morphology and Systematics (Archostemata, Adephaga, Myxophaga, Polyphaga partim) . 1st edition. de Gruyter , 2005, ISBN 3-11-017130-9 (English).