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Setae on the foreleg of a mayfly. Annelid setae are stiff bristles present on the body. They help, for example, earthworms to attach to the surface and prevent backsliding during peristaltic motion. These hairs make it difficult to pull a worm straight from the ground. Setae in oligochaetes (a group including earthworms) are largely composed of ...
The Burgess shale animals like Sidneyia from about have been classified as chelicerates, the latter because its appendages resemble those of the Xiphosura (horseshoe crabs). However, cladistic analyses that consider wider ranges of characteristics place neither as chelicerates.
Trichobothria (singular trichobothrium) are elongate setae ("hairs") present in arachnids, various orders of insects, and myriapods that function in the detection of airborne vibrations and currents, and electrical charge. [1] In 1883, Friedrich Dahl observed that they were deflected by the sound waves from a violin and labelled them 'hearing ...
They may be irregular or align in two or more rows. The number of rows, the number of setae in each row, the size and the thickness are significant. In many groups, the acrostical setae are replaced by setulae or hairs. prescutellar (psc) two acrostical bristles, more developed than the other acrosticals, inserted in front of the scutoscutellar ...
Polychaete annelids (polychaeta literally meaning "many bristles") are named for their chaetae. In Polychaeta, chaetae are found as bundles on the parapodia , paired appendages on the side of the body. [ 1 ]
Drawing of the statocyst system Statocysts (ss) and statolith (sl) inside the head of sea snail Gigantopelta chessoia. The statocyst is a balance sensory receptor present in some aquatic invertebrates, including bivalves, [1] cnidarians, [2] ctenophorans, [3] echinoderms, [4] cephalopods, [5] [6] crustaceans, [7] and gastropods, [8] A similar structure is also found in Xenoturbella. [9]
Abdomen or opisthosoma: One of the two main body parts , located towards the posterior end; see also Abdomen § Other animals; Accessory claw: Modified setae at the tip of the tarsus in web-building spiders; used with tarsal claws to grip strands of the web [1]
The Mygalomorphae, which first appeared in the Triassic period, [96] are generally heavily built and ″hairy″, with large, robust chelicerae and fangs (technically, spiders do not have true hairs, but rather setae). [114] [105] Well-known examples include tarantulas, ctenizid trapdoor spiders and the Australasian funnel-web spiders. [13]