Archostemata
| Archostemata | ||||||||||||
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Tenomerga mucida, from the Cupedidae family |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Archostemata | ||||||||||||
| Kolbe , 1908 |
The suborder of the Archostemata is a very small suborder of the beetles (Coleoptera) with only five families and currently 40 known species .
features
The medium-sized beetles reach a body length of 5 to 26 millimeters and a width of two to nine millimeters. Exceptions to this are Micromalthus debilis and Crowsoniella relicta , which are significantly smaller and only about 1.5 millimeters wide. The color of the body goes from light gray to brown to black. The notopleural suture on the prothorax is visible, the cervical sclerite between the head and prothorax is missing. All species with the exception of the two above have only partially sclerotized winglets . They are only fully sclerotized on the nine longitudinal arteries and on the anterior and posterior ends. The longitudinal arteries are connected by numerous transverse arteries. The space within these veins is thin and transparent. The body of the beetle is again covered with scales in all species with the exception of the two species mentioned above, which in some species form colored patterns. The eleven-part antennae are thread-shaped (filiform) or pearl-like (moniliform). In some species they are only as long as the head, in others they are approximately the length of the body. With the exception of the two types mentioned above, the prementum , a sclerite on the labium , is enlarged and has an apodeme and specialized muscles in the center. In these species, the prementum works like a flap that closes the mouth opening and covers the maxillary and labial lobes. The shape of the latter suggests that the beetles feed on pollen and plant sap. The mandibles are usually very strong and have sharp, vertically or horizontally aligned cutting surfaces.
The following autapomorphies occur in the larvae of the Archostemata : The head capsule of the larvae has posteromedian indentations on the back and abdomen, their mandibles have three apical teeth, the cardo of the maxilla has an additional lateral part, the wedge-shaped ligula on the labium is enlarged, starting with the second In the larval stage, ampullae are formed at the end of the abdomen, and the tenth segment of the abdomen is severely reduced. The adults differ from the other groups of beetles by the shape of the prementum and a large, rounded dorso-lateral bump on the basalar , a sclerite on the episternum .
Occurrence
Representatives of this suborder are found in South America (Cupedidae, Ommatidae), North America (Cupedidae, Miromalthidae), Europe (Crowsoniellidae), Asia (Cupedidae, Jurodidae), Africa (e.g. Tenomerga leucophaea of the Cupedidae) and Australia (Cupedidae, Ommatidae) .
Fossil evidence
Fossil representatives of this group have been identified from the Lopingian (Upper Permian). But they are not closely related to the genera known from the Cisuralium (Lower Permian), such as Tshekardocoleus . Groups such as Protocoleoptera, Permocupedidae, Rhombocoleidae and Triadocupedidae belong to the most primitive representatives of the order of the beetles, but all but the latter became extinct at the beginning of the Triassic ; the Triadocupedidae survived until the beginning of the Jurassic . According to the latest findings, the Archostemata are not related to the oldest beetles, since they belong to the stem line of the entire beetle. However, all recent species of the archostemata represent a monophyletic group with many primeval features.
The Archostemata showed the greatest biodiversity in the Mesozoic , where the Ommatidae were very common in the Palearctic and representatives of the Cupedidae also lived in Europe. Several species of Cupedidae have been found in Baltic amber and from fossil deposits between 49 million and two million years old. During the Ice Ages, the Cupedidae disappeared from Europe and were no longer able to establish themselves afterwards.
Way of life
The way of life of most of the species of Archostemata is still unknown. All known species live on fungal dead wood. For them, the type of wood seems to be less important than the degree of rotting. At least Micromalthus debilis and Tenomerga cinerea are known to develop on both hardwood and softwood. The larvae usually have an elongated, parallel-sided body and short, six-limbed legs. The mouthparts and the digestive tract are typical of wood-boring beetle larvae. Micromalthus debilis has a very unusual way of life for beetles. The species develops with four completely different larval types, which also includes unisex reproduction through pedogenesis .
Taxonomy and systematics
When Hermann Julius Kolbe described it in 1908, the subordination originally only included the Cupedidae family, but four more families have now been added to it, although the position of the Jurodidae is currently still uncertain. The monophyly of the archostemata is well founded on the basis of the autapomorphies. The Cupedidae and Micromalthidae as well as the Crowsoniellidae and the Ommatidae are sister taxons . The Jurodidae are added to the group because they have similar structures on the thorax . However, the veining and folding of the wings speaks against the classification, which speaks in favor of classification under the Polyphaga . However, since no synapomorphism has yet been found in the Jurodidae and a subgroup of the Polyphaga, the family is provisionally assigned to the Archostemata. The following families are included in the Archostemata:
- Ommatidae Sharp & Muir, 1912 (6 species)
- Crowsoniellidae Iablokoff-Khnzorian, 1983 (1 species)
- Micromalthidae Barber, 1913 (1 species)
- Cupedidae Laporte, 1836 (31 species)
- Jurodidae Ponomarenko, 1985 (1 species)
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 (English).
- ↑ Riddle about the original beetle solved. Springer Verlag, accessed April 6, 2008 .
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).