Ceratocanthidae
| Ceratocanthidae | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Ceratocanthidae | ||||||||||||
| Cartwright & Gordon , 1971 |
Ceratocanthidae is a family of beetles from the superfamily Scarabaeoidea . The family is probably the least studied group of the superfamily.
features
Beetle
The beetles are 2.0 to 9.0 millimeters long. You can usually curl your body so that all extremities are protected within a compact ball. Their bodies are brown, black, greenish, or tinged with purple and often have a metallic sheen. The head is angled sharply downwards. The eight to ten- segment antennae have a three-segment lobe at the end. The triangular scapus is enlarged. The compound eyes are at least partially divided. Their ommatidia are of the euconic type. The frontal plate ( clypeus ) has no tubercles or horns. The labrum is shortened and partially covered below the edge of the front plate. The tip of the epipharynx is sclerotized ; towards the body ( proximal ) it is membranous. In its sclerotized areas ( tormae ) the median normal process is formed, the lateral ones are formed individually or twice. The mandibles have a sclerotized base and a sharp point, as well as a well-developed mesial brush. In the genus Pterorthochaetes, this is divided into a distal and a mesial crest. The galea is usually large and, in some species, has a dorsal and ventral joint scleritis , or is sclerotized proximally. The Palpi are four-membered, with the exception of Pterorthochaetes , where they are three-membered.
The broad pronotum is extended to the side. On the legs, the hips ( coxes ) of the front legs are conical and clearly protruding. The hips of the middle legs are sloping. The rails ( tibia ) of the middle and rear legs are horizontally flattened and broadened. An empodium is missing. The upper wings (elytres) are convex and have a very differently structured or very smooth surface. In some species they are hairy. The tracheal openings on the mesothorax are of the general type, but the intersegmentals are specially modified. The extremely long and narrow wire 1Ax-FSc2 on the wings is strongly directed forward. The tracheal openings on the abdomen are all functional. The last pair is on the tergite of the corresponding segment. The male genitals are structured differently. Their basal part is usually asymmetrical and unevenly sclerotized. In some species a ventral or lateral apophysis is formed. The parameters are usually small in relation to this basal part and also mostly asymmetrical. With the exception of the genera Pseudopterorthochaetes and Pterorthochaetes, the median lobe is greatly reduced. The saccus is large and equipped with several fittings, but the fittings can also be receded or missing. The genital capsule is well developed or even regressed, depending on the species. It is symmetrical or asymmetrical. The female genitals consist of a ninth tergite, membranous on the midline, and have no styli. In some species sclerites are formed on the copulatrix bursa .
Larvae
The body of the larvae is shaped in a broad C. The segments of the thorax and the first six abdominal segments are divided into three folds on the back. Ocelli are not trained. The frontoclypeal suture can be formed or absent. The antennae are four-part. They have a large sensory mark on the last link that is roughly half the surface area. The mandibles have a dorsally angled keel. The Galea and Lacinia are clearly separated from each other. The hind legs are not shortened in length. The larvae lack the closing mechanism at the tracheal openings.
distribution
The Ceratocanthidae are pantropically distributed. Only a few species occur in the temperate regions of the two Americas, South Africa and the southeastern Palearctic . The family is not represented in Europe, only three species occur in North America north of Mexico. The majority of the species inhabit tropical rainforests, a few also live in temperate or tropical seasonal forests, or in habitats with parts of savannah and forest.
Way of life
The adults were usually found in dead plant material, such as soil litter, but are also attracted by artificial light sources at night. However, they can also be found together with the larvae in dead wood and under bark. Some species are associated with ants and termites and are apparently specially adapted for this. So you can bend your head and pronotum sharply and put your legs on to protect your stomach. The species of the genus Ivieolus could only be collected in large numbers in traps for flying animals. They are strongly adapted in their body shape. Their mouthparts suggest that they eat mushrooms, but some authors even suspect that these animals live in the air at all.
Taxonomy and systematics
The family is currently divided into three subfamilies, comprising about 40 genera and 320 species, although about as many species that have already been discovered and that are assigned to the family are still undescribed. About 180 species in 16 genera are known from the New World so far. The relationships between the three subfamilies are unknown.
The monophyly of the family is justified by the following two autapomorphies of the adults: The tracheal openings on the mesothorax are of the general type and the wing vein 1Ax-FSc2 is strongly directed forward and extremely long and narrow. It is very likely that the family is one of the more developed groups within the group of close relatives of the sugar beetles (Passalidae). The characteristics of the larvae suggest a close relationship with the Hybosoridae and it cannot be ruled out that the family actually represents a more developed group within the Hybosoridae.
supporting documents
Individual evidence
- ↑ a b c d e f g 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. 381 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).