Search results
Results From The WOW.Com Content Network
A spinneret is a silk-spinning organ of a spider or the larva of an insect. Some adult insects also have spinnerets, such as those borne on the forelegs of Embioptera. [1] Spinnerets are usually on the underside of a spider's opisthosoma, and are typically segmented. [2] [3] While most spiders have six spinnerets, some have two, four, or eight. [4]
This hypothesis was based on the supposed presence of unique spider features such as silk-producing spinnerets and the opening of a venom gland on the fang of the chelicera. Further study – based on new fossils from a comparable Devonian locality called South Mountain – and comparison with other material from the Permian of Russia , i.e ...
Most of these early segmented fossil spiders from the Coal Measures of Europe and North America probably belonged to the Mesothelae, or something very similar, a group of spiders with the spinnerets placed underneath the middle of the abdomen, rather than at the end as in modern spiders. They were probably ground-dwelling predators, living in ...
Later, partly on the basis of a supposed spinneret, it was identified as a spider and named Attercopus fimbriunguis. [2] Further specimens of this species were found, and when examined in detail, along with those assigned to the genus Permarachne , features inconsistent with their placement as spiders were revealed.
The cribellate spiders were the first spiders to build specialized prey-catching webs, later evolving into groups that used the spinnerets solely to make webs, instead using silk threads dotted with droplets of a sticky liquid (like pearls on a necklace) to capture small arthropods, and a few large species even small bats and birds.
Attercopus fimbriunguis, from in the Devonian period, bears the earliest known silk-producing spigots, and was therefore hailed as a spider, [56] but it lacked spinnerets and hence was not a true spider. [57] Rather, it was likely sister group to the spiders, a clade which has been named Serikodiastida. [58]
Spiders (order Araneae) are air-breathing arthropods that have eight limbs, chelicerae with fangs generally able to inject venom, [2] and spinnerets that extrude silk. [3] They are the largest order of arachnids and rank seventh in total species diversity among all orders of organisms .
Chimerarachne is not ancestral to spiders, being much younger than the oldest spiders which are known from the Carboniferous, but it appears to be a late survivor of an extinct group which was probably very close to the origins of spiders. It suggests that there used to be spider-like animals with tails which lived alongside true spiders for at ...