Micropholcommatidae
| Micropholcommatidae | ||||||||||||
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Parapua punctata , male |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Micropholcommatidae | ||||||||||||
| Hickman , 1943 |
The Micropholcommatidae are a family of real spiders (Araneomorphae) and belong to the superfamily of orb web spiders (Araneoidea). The 33 very small species are native to Tasmania , Queensland , New Zealand as well as New Guinea , Chile and Brazil . Little research has been done into their way of life. According to some observations, their webs resemble those of the crested web spiders (Theridiidae).
features
Representatives of the Micropholcommatidae are very small, dark spiders with a body length of one to two millimeters. They have six or eight eyes, with the two front middle eyes in the case of eight eyes being very small and absent in the six-eyed species. The eyes of the side pairs of eyes are each very close together. However, these pairs of eyes are clearly separated from the middle pairs of eyes.
The edges of the chelicerae are toothed on both sides. The males also have hook teeth on the dorsal edge of the chelicerene notch, in some species the females also have this. The cheliceric gland, which consists of a few pores , is located on a small hill . The rectangular labium is at least as wide as it is long. The basal segments of the pedipalps , called the maxillae , lie close together and have a series of smaller teeth called serrula . The pedipalps of the females are smaller and have no claw, while the males have three claws. The kneecap (patella) and the lower leg ( tibia ) of the pedipalps are severely deformed. The lower leg forms a plate that is pressed against the dorsal part of the tarsus .
The genitals of the males are particularly variable in the shape of the embolus and come in two forms. In some species the embolus is short and tubular, in others it is long and curled. In both cases there is an appendage to the tegulum , the part of the globe that houses the vas deferens . Micropholcommatidae are entelegyne spiders. This means that the external female sex organ is the epigyne , so there are two separate vas deferens; one to the two spermathecae and one to the uterus .
The front body is only vaguely separated from the highly elevated cephalothorax . The fovea is either completely absent or very weak. The sternum is about as long as it is wide and rounded at the back. The metatarsi are shorter than the tarsi, which have three toothed claws. On the metatarsi as well as the tibiae there are also small, flexible hair-like structures, which are known as trichobothria .
The abdomen ( opisthosoma ) is egg-shaped and provided with a sclerotized plate (scutum) or a leathery skin. The fold of the epigastrium is also often covered with sclerotized plates. The six spinnerets are close together. The piriform spinnerets are shortened at the base. The flagelliform spinnerets are smaller than the neighboring aggregate spinnerets. Micropholcommatidae produce sticky filaments and thus count among the ecribellate spiders . The colullus, on the other hand, is very pronounced.
For breathing, the representatives of the Micropholcommatidae have a system of poorly developed tracheas instead of the book lungs . In the subfamily Textricellinae this is only in the front area. In the subfamily Micropholcommatinae there is a posterior opening in the area of the spinning glands and an anterior opening that connects to a larger chamber.
Systematics and phylogeny
Currently the family of the superfamily orb web spiders (Araneoidea) is assigned. A study by Karin Schütt in 2003 showed that the Micropholcommatidae should be synonymous with the family of dwarf ball spiders (Anapidae), as this would otherwise be paraphyletic . This has already been adopted by the World Spider Catalog . The family is divided into two subfamilies, comprising eight genera with 33 species.
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Micropholcommatinae
- Eterosonycha Butler , 1932
- Micropholcomma Crosby & Bishop , 1927
- Olgania Hickman , 1979
- Parapua Forster , 1959
- Pua Forster , 1959
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Textricellinae
- Teutoniella Brignoli , 1981
- Textricella Hickman , 1945
- Tricellina Forster & Platnick , 1989
literature
- Rudy Jocqué, Ansie Dippenaar-Schoeman: Spider Families of the World . Royal Museum for Central Africa, Tervuren 2007, ISBN 90-75894-85-6 , p. 336.
Individual evidence
- ↑ Schütt, K. (2000): The limits of the Araneoidea (Arachnida: Araneae). Australian Journal of Zoology 48, pp. 135-153.
- ↑ a b Schütt, K. (2003): Phylogeny of Symphytognathidae sl (Araneae, Araneoidea). Zoologica Scripta 32, pp. 129-151, doi : 10.1046 / j.1463-6409.2003.00103.x .
- ↑ Natural History Museum of the Burgergemeinde Bern: World Spider Catalog Version 17.5 - Anapidae . Retrieved December 23, 2016.
