Opiliones
Aka Harvest Men or Daddy Long legs.Daddy-long-legs/Daddy-longlegs/Daddy Long-legs, Granddaddy-long-legs, Harvest Spiders, Shepherd Spiders, Phalangids, Opilionids. The former scientific name for Opiliones was Phalangida and this name still often appears in the literature. The common name "daddy longlegs" also is used for the crane fly (Tipulidae) and the cellar spider (Pholcidae) (Crawford 2005).[encyclopedia]
Description
Opiliones are delicate, shy forms that are among the largest of arachnids in woodlands.[book]
Easily separated from spiders by the broad fusion of the two body segments, so that the body appears to be composed of a singular segment. Harvestmen do not possess silk glands, and can't spin webs. Unlike spiders, harvestmen lack venom glands associated with their chelicerae (mouthparts). Uniquely among the arachnids fertilization is direct: males of most taxa possess a penis (also referred to in the literature as pene, aedagus or intromittent organ).[bug guide] Harvestmen are known for their exceptionally long walking legs, compared to body size, although there are also short-legged species. The difference between harvestmen and spiders is that in harvestmen the two main body sections (the abdomen with ten segments and the cephalothorax—or the prosoma and opisthosoma) are broadly joined, so that they appear to be one oval structure; they also have no venom or silk glands. In more advanced species of harvestment, the first five abdominal segments are often fused into a dorsal shield called the scutum, which is normally fused with the carapace. Sometimes this shield is only present in males. The two most posterior abdominal segments can be reduced or separated in the middle on the surface to form two plates lying next to each other. The second pair of legs are longer than the others and work as antennae. This can be hard to see in short-legged species.
Typical body length does not exceed 7 millimeters (about 5/16 inch), with some species smaller than one millimeter, although the largest species Trogulus torosus (Trogulidae) can reach a length of 22 millimeters (Pinto-da-Rocha et al. 2007). However, leg span is much larger and can exceed 160 millimeters (over 6 inches).[encyclopedia
Location Range and habitat
Global, except Antarctica-range
forests, grasslands, wetlands, mountains, caves, chaparral, and anthropogenic habitats
species
>6600 species worldwide arranged into ~45 families of 4 suborders (of which Laniatores is by far the largest, with >4100 species) [Bug page]
ex.
'Activity'
Most species are nocturnal and colored in hues of brown, although a number of diurnal species are known, some of which have vivid patterns in yellow, green, and black with varied reddish and blackish mottling and reticulation.
Noted
Although harvest men are a fascinating group of arachnids the dramatic increase in environmental disturbance around the world especially in tropical regions may have driven many species to extinction even before there formal description by taxonomists. Human activities including pesticide use forestry operations air and soil pollution fire and even the introduction of domestic animals have a tremendous impact on the habitats they depend on. All formerly considered endangered are most were cave dwellers who are particularly sensitive to disturbances of habitat [Harvard bookHarvestmen: The Biology of Opiliones Ricardo Pinto-Da-Rocha, Glauco Machado, and Gonzalo Giribet (eds.). 2007. Harvard University Press.]