Forehead weapon carrier
Forehead weapon carrier | ||||||||||||
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Gauntlet ( oryx gazella ) |
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Scientific name | ||||||||||||
Pecora | ||||||||||||
Flower , 1883 | ||||||||||||
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The forehead weapon bearers (Pecora) are a taxon (a systematic group of creatures) within the artifacts .
features
The forehead armament
The eponymous feature are the forehead weapons. These are mostly outgrowths of the frontal bone , which are built differently depending on the family. However , they are absent in two genera, the musk deer and the water twist .
- The giraffe-like (Giraffidae) - giraffe and okapi - have bone cones that are covered with hairy skin.
- The deer (Cervidae) are characterized by antlers that grow from cone-shaped bones ("rose bushes"). It consists of bone substance and is shed and newly formed every year after the mating season.
- The hornbeams (Bovidae), on the other hand, have horns made of horny substance , which are usually retained for a lifetime. The skin that covers the bone cone sheds horny cells, which eventually thicken into a hard horny sheath. The oldest horn layers move further and further towards the horn tip and at least the outer part of the horn is hollow. With the exception of the four-horned antelope , all horn carriers have two horns.
- In the case of the fork-horned bearers (Antilocapridae), the horns are formed similarly to those of the horned bearers, but in contrast, the horn sheaths are shed annually.
The forehead weapons can be used for showing off, fighting for mating privilege and also for defense. In almost all cases they are sexually dimorphic , that is, larger in males than in females. In some species, such as almost all deer, some forest goats and the okapi , the females lack forehead armament.
Other specifications
The height of the forehead weapon carriers varies considerably. Some representatives such as the bucks or pudus are very small, in contrast to cattle or giraffes can weigh more than a ton. As artifacts , the forehead weapon bearers share the characteristics of this group, the relatively immobile feet with two or four toes, which are used for rapid locomotion. They are ruminants , so they have a four-chambered stomach, which is used to better utilize the plant food.
Distribution and way of life
Forehead weapon carriers are widespread almost worldwide, they occur in America , Eurasia and Africa . They are pure herbivores and often live in hierarchically structured groups. Some representatives (such as domestic cattle , domestic sheep and domestic goats ) have achieved worldwide importance as domestic animals, others have been distributed worldwide as park and hunting animals, but still others have been pushed to the brink of extinction by hunting and habitat destruction .
Systematics
The forehead weapon bearers are the sister group of the deer piglets , which differ from them by a three-chambered stomach and the lack of forehead weapons. Together they form the subordination of the ruminants (Ruminantia) in the order of the ungulate or the Cetartiodactyla .
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The following five recent families are included:
- The giraffe-like (Giraffidae) are composed of two externally different genera, the giraffes and the okapi .
- The musk deer or musk deer (Moschidae) are a group of deer-like, but forehead-free animals living in East Asia.
- The Gabelhorn carrier (Antilocapridae) comprise only one way out in North America living pronghorn .
- The deer (Cervidae) are made up of around 45 species, which are characterized by antlers that usually only the males wear. The species that are also widespread in Europe include the red deer , the roe deer , the elk and the reindeer .
- The horned bearers (Bovidae) are the most species-rich and diverse group. These include the cattle , goat-like , gazelle-like and several groups known as antelopes .
The internal system of the forehead weapon carriers is confusing and controversial. Although deer, musk deer and fork-horned bearers have traditionally been grouped together as deer-like (Cervoidea), different molecular studies provide different - and inconsistent - results, so that the question of a phylogenetic system of forehead weapon bearers cannot yet be clearly answered.
literature
- Wilfried Westheide , Reinhard Rieger (Hrsg.): Special zoology. Part 2: vertebrates or skulls. Spectrum Akademischer Verlag, Heidelberg - Berlin 2004, 712 pages, ISBN 3-8274-0307-3 .