Leiobunum Temporal range: | |
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female L. rotundum | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Subphylum: | Chelicerata |
Class: | Arachnida |
Order: | Opiliones |
Family: | Sclerosomatidae |
Genus: | Leiobunum C. L. Koch, 1839 |
Type species | |
Phalangium rotundum Latreille, 1798 | |
Species | |
See text | |
Diversity | |
c. 120 species |
Leiobunum is a genus of the harvestman family Sclerosomatidae with more than 100 described species. Contrary to popular belief, they are not spiders, although they share a resemblance. They are arachnids, in the order Opiliones, harvestmen. Species in Leiobunum tend to have relatively long legs compared with other harvestmen, and some species are gregarious.
The teguments are soft or subcoriaceous. The striae of the cephalothorax and of the three last abdominal segments are very distinct; those of the anterior segments are scarcely or not at all distinct. The anterior and lateral borders of the cephalothorax are smooth. The eye eminence is relatively small; smooth or, rarely, provided with small, slightly distinct, tubercles; widely separated from the cephalic border. Lateral pores small, oval, and marginal. Anal piece large, transverse-oval or semicircular, much wider than long, and much wider than the reflected borders of the eighth segment. Mandibles short, similar in the two sexes ; first joint furnished at the base below with an acute tooth. Palpi simple ; femur, patella, and tibia without any process and without projecting angles ; maxillary lobe provided at the base with two strong, conical teeth. Maxillary lobe of the second pair of feet very long, nearly straight from the base, not attenuated, directed mesad nearly horizontally, and united on the ventro-meson to the lobe from the opposite side without forming a sensible angle; the two together lightly arched on the cephalic border, and forming an even curve. Sternal piece large, slightly contracted between the fourth pair of coxae, gradually enlarging and obtusely truncate cephalad. The feet are very long and slender; tibia of the second pair with a few false articulations. Palpal claw denticulate. [1] Many Leiobunum species tend to form clusters of several, but some up to 1,000 and more individuals.
An as yet undescribed species of Leiobunum was first found in the Netherlands in October 2004, although reports date back to at least 2002. Since then, it has been identified from Germany, Switzerland, and Austria. It is distinct from all known Central European species and was probably introduced. This species has a strong tendency to group together, most of the time protected from wind and direct sunlight, and stay in one place for weeks. They swarm out at night to hunt on their own. When disturbed, they move their bodies up and down in a fast, rhythmic motion, with individuals moving away from the disturbance. The first juvenile stages seem to live on the ground below rocks and debris. The largest observed aggregation counted 770 individuals. [2]
[see also Leiobunum albigenium Sorensen, 1911 (Syria)]
The Opiliones are an order of arachnids, colloquially known as harvestmen, harvesters, harvest spiders, or daddy longlegs. As of July 2024, over 6,650 species of harvestmen have been discovered worldwide, although the total number of extant species may exceed 10,000. The order Opiliones includes five suborders: Cyphophthalmi, Eupnoi, Dyspnoi, Laniatores, and Tetrophthalmi, which were named in 2014.
Theridion is a genus of tangle-web spiders with a worldwide distribution. Notable species are the Hawaiian happy face spider (T. grallator), named for the iconic symbol on its abdomen, and T. nigroannulatum, one of few spider species that lives in social groups, attacking prey en masse to overwhelm them as a team.
Pardosa is a large genus of wolf spiders, commonly known as the thin-legged wolf spiders. It was first described by C. L. Koch, in 1847, with more than 500 described species that are found in all regions of the world.
The Phalangodidae are a family of harvestmen with about 30 genera and more than 100 described species, distributed in the Holarctic region.
The Sclerosomatidae are a family of harvestmen with about 1,300 known species. One former subfamily has been recently removed to form a new family, Globipedidae.
The Triaenonychidae are a family of harvestmen with about 120 genera and more than 440 described species.
The Nemastomatidae are a family of harvestmen with about 170 described species in 16 recent genera. Several fossil species and genera are known.
The Stygnopsidae are a small family of harvestmen, with almost all species found in Mexico.
Samoidae is a family of the harvestman infraorder Grassatores with about fifty described species.
Prionostemma is a large genus of harvestmen in the family Sclerosomatidae from Mexico, Central America, and South America.
Metopilio is a genus of harvestmen in the family Globipedidae from Mexico and Central America.
Nelima is a genus of harvestmen in the family Sclerosomatidae.
Taracus is a genus of harvestman, or Opiliones, typically found living in limestone and lava caves in the United States. They grow to a size of 2.0–5.5 mm (0.08–0.22 in).