The Collaborative International Dictionary
Pedipalp \Ped"i*palp\, n. [Cf. F. p['e]dipalpe.] (Zo["o]l.) One of the Pedipalpi.
n. Either of a second pair of appendages, near the mouth of a spider, homologous to the mandibles in crustaceans.
Pedipalps (commonly shortened to palps or palpi) are the second pair of appendages of chelicerates– a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to the chelicerae ("jaws") and anterior to the first pair of walking legs.
Pedipalps are composed of six segments or articles: the coxae, a single trochanter, the femur, a short patella, the tibia, and the tarsus. In spiders the coxae frequently have extensions called maxillae or gnathobases, which function as mouth parts with or without some contribution from the coxae of the anterior legs. The limbs themselves may be simple tactile organs outwardly resembling the legs, as in spiders, or chelate weapons of great size, as in the scorpions. Comparative studies of pedipalpal morphology may suggest that leg-like pedipalps are primitive in arachnids. At present, the only reasonable alternative to this view is to assume that Xiphosurans reflect the morphology of the primitive arachnid pedipalp and to conclude that this appendage is primitively chelate. Chelate or sub chelate pedipalps are found in several arachnid groups, i.e. Ricinulei, Thelyphonida, Scorpions and pseudoscorpions, but the chelae in most of these groups may not be homologous with those found in Xiphosura. The pedipalps are distinctly raptorial (modified for seizing prey) in the Amblypygi, Thelyphonida, Schizomida and some Opiliones belonging to the laniatorid group.
Pedipalps are traditionally thought to be homologous with mandibles in crustaceans and insects, although more recent studies (e.g. using Hox genes) suggest they are probably homologous with the crustacean second antennae.
Usage examples of "pedipalp".
His distress was obvious and it was mirrored by the postures and pedipalp positions of the soldiers around him.
She paused, her head slightly bowed, and with a delicate swipe of her pedipalp she wiped away a crumb of fat from her chelicerae.
Its movement started at its pedipalps and rolled back over its body, flipping through the fine black hairs that covered its back.
One of his long, sinewy pedipalps shot down from his cephalothorax and silenced the shrilling alert signal on his wraparound helm console.
The alien said something, waving its pedipalps and clicking its mandibles as its chelicerae subtly changed positions.
She scraped the fat from her tongue with her chelicerae and pulled it off with her pedipalps, patting it back onto her lump.
She put her pedipalps up to hold them still and her tailwhip began to vibrate.
The spider saw Betsy, too, for it reared up, twiddled its pedipalps with conspicuous insolence, and emitted a crackling purr.