Real spiders
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Zebra jumping spider ( Salticus scenicus ) with prey |
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| Araneomorphae | ||||||||||||
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The real spiders (Araneomorphae) are the most species-rich suborder of arachnids from the order of the spiders . Older names for the Araneomorphae, which refer to certain characteristics of the group, are Labidognathae and Cribellatae .
features
The real spiders are small to at most medium-sized spiders. Originally they built nets , but today there are a number of free-hunting families . The front middle pair of the spinning glands was originally transformed into a cribellum , with the help of which a glue-free fishing wool can be produced, but it can also be reduced to a hill-like structure ( colulus ) or completely. The posterior lateral spinnerets are only one or two-part.
The chelicerae of the Araneomorphae are in contrast to the more original forward-facing arrangement in the tarantulas (orthognath) obliquely or vertically downwards (labidognath). This allows the two chelicerae to move against each other, which allows prey to be grasped more effectively. The chelicerae are supplemented as mouth parts by the coxae of the pedipalps . These are transformed into broad oval plates (Gnathocoxae) covered with bristles, which follow the movement of the chelicerae and thus, together with the lower lip, form a delimitation of the oral cavity. In the male animals of the more highly developed forms ( entelegynae ), the tip of the pedipalus is also expanded to a mating organ (embolus), which is a perfect fit with the external female sexual organ ( epigyne ).
In all genera, apart from the original Hypochilus, there is only a single pair of fan-shaped lungs as the respiratory organ , the second being replaced by a pair of tubular trachea. In addition, there is usually only one other pair of endapophyseal trachea . The heart still has four pairs of ostia in Hypochilus , but only three in most Araneomorphae and only two pairs of ostia in the dwarf six-eye spider (Oonopidae) . A single pair of coxal glands is present as an excretory organ .
Systematics of the real spiders
External system
The real spiders are one of three sub-orders of the spiders (Araneae). With around 36,000 species, they make up around 90% of the known species of spider.
| Spiders (Araneae) |
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Internal system
Two groups can be distinguished within the real spiders:
- The Palaeocribellatae are the most primitive group and still have orthognathic chelicerae, but pedipalps with Gnathocoxae, two book lungs and a heart with four ostia. The cribellum is a short, blunt cone. This only includes the Hypochilidae family .
- The Neocribellatae comprise the superfamily Austrochiloidea with the two families Austrochilidae and Gradungulidae and opposite these the Araneoclada , which in turn can be subdivided into the Haplogynae and the Entelegynae characterized by an epigyne .
| Real spiders (Araneomorphae) |
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literature
- Hans-Eckhard Gruner (Ed.): Textbook of Special Zoology, Volume I: Invertebrates, Part 4: Arthropods (without Insecta) . 4th edition. Gustav Fischer, Jena, Stuttgart, New York 1993, ISBN 3-334-60404-7 , pp. 183, 244 .
- Jonathan A. Coddington, Herbert W. Levi: Systematics and Evolution of Spiders (Araneae) . In: Annual Review of Ecology and Systematics . tape 22 , 1991, pp. 565–592 ( full text PDF, English).
