CT scans reveal new muscles in horseshoe crab appendages

Digital dissection shows that two horseshoe crab appendages—the pushing leg and the male pedipalp—each have one more muscle than had been thought, according to a study published February 14, 2018 in the open-access journal ...

A 508-million-year-old sea predator with a 'jackknife' head

Paleontologists at the University of Toronto (U of T) and the Royal Ontario Museum (ROM) in Toronto have entirely revisited a tiny yet exceptionally fierce ancient sea creature called Habelia optata that has confounded scientists ...

Researcher studies the feeding habits of stomatopod crustaceans

Biology Letters talks to Maya deVries, author of a recently published article that describes the feeding habits of stomatopod crustaceans with two kinds of highly specialized feeding appendages; those with elongated spear-like ...

Critical protein discovered for healthy cell growth in mammals

(Phys.org) —A team of researchers from Penn State University and the University of California has discovered a protein that is required for the growth of tiny, but critical, hair-like structures called cilia on cell surfaces. ...

How did we get four limbs? Because we have a belly

All of us backboned animals – at least the ones who also have jaws – have four fins or limbs, one pair in front and one pair behind. These have been modified dramatically in the course of evolution, into a marvelous variety ...

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In invertebrate biology, an appendage is an external body part, or natural prolongation, that protrudes from an organism's body (in verterbrate biology, an example would be a vertebrate's limbs). It is a general term that covers any of the homologous body parts that may extend from a body segment. These include antennae, mouthparts (including mandibles, maxillae and maxillipeds), wings, elytra, gills, walking legs (pereiopods), swimming legs (pleopods), sexual organs (gonopods), and parts of the tail (uropods). Typically, each body segment carries one pair of appendages.

An appendage which is modified to assist in feeding is known as a maxilliped or gnathopod.

Appendages may be uniramous, as in insects and centipedes, where each appendage comprises a single series of segments, or it may be biramous, as in many crustaceans, where each appendage branches into two sections. Triramous (branching into three) appendages are also possible.

All arthropod appendages are variations of the same basic structure (homologous), and which structure is produced is controlled by "homeobox" genes. Changes to these genes have allowed scientists to produce animals (chiefly Drosophila melanogaster) with modified appendages, such as legs instead of antennae.

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