Crowsoniella relicta
| Crowsoniella relicta | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name of the family | ||||||||||||
| Crowsoniellidae | ||||||||||||
| Iablokoff-Khnzorian , 1983 | ||||||||||||
| Scientific name of the genus | ||||||||||||
| Crowsoniella | ||||||||||||
| Pace , 1976 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Crowsoniella relicta | ||||||||||||
| Pace, 1976 |
Crowsoniella relicta is the only species of the beetle family of the Crowsoniellidaedescribed so far. The family belongs to the archostemata group, which is very original compared to the other suborders of the beetles. So far only three specimens ( holotype and two paratypes) have been discovered in central Italy. The genus is named after the British zoologist Roy Crowson (1914–1999).
features
The beetles are 1.3 to 1.7 millimeters long and have a flattened, reddish yellow to dark brown body. Its surface is smooth and shiny and unscaled. Tubercles or grooves are not formed. The mouthparts are prominent (prognath) and somewhat wider than long. Shortly before its base, the head suddenly tapers into a neck. The compound eyes lying on the side below the antennae deflections consist of only a few ommatidia . The area of the sensor deflections is relatively large and noticeable. The seven-part antennae are about as long as the head and finely haired. Your last segment is thickened. The mouthparts are severely receded. The labrum , the clypeus (forehead plate) and the frons (forehead) are fused together and show no visible seams. The mandibles are stunted, instead of the maxilla and the labium there are two pairs of palps, which consist of a short first and a spherical second segment. The latter segment has four sensory hairs on each tip. With the maxillary palps there are two additional sensory hairs on the side at the tip, with the labial palps there is only one.
The pronotum is about one and a half times wider than the head and slightly narrower than the wing . The prothorax has conspicuous indentations on the upper side at the front corners, to which the feelers can be placed, as well as indentations for the tarsi or tibia of the first pair of legs on the underside on the sides of the prosternum . The notopleural suture is not formed. The indentations for the coxes are open to the rear. The mesothorax , metathorax and the first abdominal segment are fused. The upper wings are shiny, almost smooth and only very flat, poorly recognizable punctiform structured. A short bristle emerges from each of these depressions. The second, membranous pair of wings (alae) is not developed. You can see five contiguous ventrites (visible abdominal sclerites ) on the abdomen, which are located on sternites 2 and 3 and 4 to 7. In the middle of the anterior ventricle there is an extension that extends forward between the coxae of the middle pair of legs. The fourth and fifth sternite have laterally strong, forward-facing processes.
Way of life
Crowsoniella relicta probably lives under chestnuts . Due to the shape of the mouthparts, it is assumed that the adults only feed on liquids. Nothing is known about the development cycle, larvae have not yet been discovered.
Systematics
The species has evolved far away from the rest of the archostemas and has many autapomorphies . Their systematic position is not fully clarified. Roberto Pace put them in their description in 1976, mainly because of the indentations on the pronotum for the antennae, in the family Tetraphaleridae, which are now regarded as a subfamily ( Tetraphalerinae ) of the Ommatidae . The exact position of these indentations, however, is different from that of the Tetraphalerinae, so that synapomorphism can not be assumed. Crowsoniella is thought to be closest related to the Ommatidae family because of the abutting ventrites. This suggestion is also reinforced by the lack of an exposed labrum.
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 (English).
- ↑ Crowsoniella relicta. Fauna Europaea, accessed January 31, 2010 .
- ↑ Quentin Wheeler: Professor Roy Albert Crowson 1914-1999. In: The Coleopterists Bulletin. Vol. 54, No. 1, 2000, pp. 120-121.
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).
- Roberto Pace: Remarkable new beetle from central Italy. In: Nature. Volume 263, September 30, 1976, p. 375 ( online ).