Trachypachidae
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| CG Thomson , 1857 |
The Trachypachidae are a species-poor family of beetles within the Adephaga . The family includes two genera and six species .
features
Beetle
The beetles are 3.8 to 7 millimeters long, black and have a more or less smooth and shiny body surface. The genus Systolosoma has a shiny metallic surface structure. The beetles look similar to ground beetles and have a clear constriction between the pronotum and the wings . The head has forward-facing mouthparts and is relatively short. The compound eyes are well developed and easily protrude. The antennae are thread-like, the last segment has a faint down. The upper wings of the genus Trachypachus are largely smooth and only have a weak point-like structure. The genus Systolosoma has irregular spots with a metallic sheen on them. The third and fourth sternite are fused on the abdomen , the last, seventh sternite is broadly rounded.
Larvae
The larvae are elongated and slightly flattened. Their margins are almost parallel. The sclerotized parts of the body are brownish. The one facing the head has mouthparts pointing forward and has six point eyes ( ocelli ). The antennae are four-part. The mandibles are relatively short. The stipes are short, the lacinia is absent. The galea is two-part. The pronotum is larger than the following segments. The legs have double claws. The ninth abdominal segment is normally developed, the horn-like urogomphi either connected to it or absent, as in Systolosoma breve .
Way of life
Little is known about the way of life of this family. Roy Crowson described the family as inhabitants of humid habitats, but both the larvae and the adults of all Trachypachus species are xerophilic and this independent of adjacent waters. From Trachypachus gibbsii is known to rivers with sandbanks poplar growth in dry gravel and fine sand, covered with leaves, inhabited. Trachypachus holmbergi lives in open or slightly shaded areas that are covered with leaves or needles. Systolosoma breve inhabits rainforests, Systolosoma lateritium was found in forests with vegetation of Coihue southern beech ( Nothofagus dombeyi ) and Lenga southern beech ( Nothofagus pumilio ).
The beetles and their larvae are predatory and eat their victims by means of extraintestinal digestion . Nothing is known about the prey animals and their hunting behavior. Nothing is known about the number of larval stages either.
Systematics and occurrence
The monophyly of the Trachypachidae is mainly supported by autapomorphies of the larvae. This includes, among other things, the absence of sensory hair on the side of the third antennae, instead there is a sensory field on the ventral side, the tip of the third maxillary probe has additional hairs and the ninth tergite has eight bristles. The adults are differentiated from the other families of beetles by the shape of the parameters .
The genus Trachypachus includes four species. Trachypachus zetterstedtii is palearctic , the other three species occur in western North America. Trachypachus holmbergi is distributed from California to Alberta, Trachypachus gibbsii from the southern Sierra Nevada to the southern tip of British Columbia and Trachypachus slevini in western Oregon and Washington. The genus Systolosoma comprises two species that occur in central and southern Chile: Systolosoma breve and Systolosoma lateritium . The subfamily Eodromeinae with six genera is only known from fossil finds from the Triassic , Jurassic and Early Cretaceous from Asia and probably also from the late Jurassic from Europe.
supporting documents
Individual evidence
- ↑ a b c d e f 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. 116 ff . (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).
