Chelicera


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chelicera

[kə′lis·ə·rə]
(invertebrate zoology)
Either appendage of the first pair in arachnids, usually modified for seizing, crushing, or piercing.

Chelicera

 

one of the first two extremities on the head of arthropods of the subphylum Chelicerata. Chelicerae, which serve to grind and crush food, are located in front of the mouth. In most animals they consist of three segments and are equipped with chelae. In spiders the chelicerae have a clawlike terminal segment, onto which the duct of the poison gland opens. In parasitic ticks and mites the chelicerae often resemble spiny piercing stylets; they frequently bear cutting lobes and hooks, with which the parasite attaches itself to the body of the host. The homologues of chelicerae in Crustacea, Myriapoda, and Insecta are the upper jaws, or mandibles.

References in periodicals archive ?
A) NBMG 10237, a single chelicera of the eurypterid Pterygotus anglicus from delta-front sediments (Kennedy et al.
Setae z4 short, not reaching to the base of setae s4; setae J2 greater than j6 in length; setae s4 greater than 3x length of setae Z1; setae Z4 greater than S2 and S5; peritreme tip pointed; membranous infold absent between genital and ventrianal shield; ventrianal shield ovoid, anterior margin straight, setae JV1 anterior to ZV2; chelicera fixed digit with 2 small teeth .
Setae z2, z4 long reaching the base of next setae in line; setae J2 = j6 in length; setae s4 less than 3x length of setae Z1; setae Z4 = S2 = S5; peritreme tip slightly rounded; membranous infold present between genital and ventrianal shield; ventrianal shield anterior margin convex, setae JV1 posterior to ZV2; chelicera fixed digit with 5 small teeth .
Dorsum wider anteriorly, rounded posteriorly; setae j3 and z4 long, reaching beyond the base of next setae in line; setae Z4 long, reaching base of setae S5; distance between S2-S4 = distance between S4-S5; chelicera fixed digit with 3 small teeth .
Dorsum paddle shaped; all dorsal setae short, not reaching to base of next setae in line; distance between S2-S4 greater than distance between S4-S5; chelicera fixed digit with 5 small teeth .
Dorsum pointed anteriorly; chelicera fixed digit with 3 small teeth; all dorsal setae short, not reaching to base of next setae in line, calyx elongate .
Chelicera fixed digit 25 (25-38) long, with 5 small teeth, movable digit without teeth.
Female holotype: Color: Overall color as described by Chamberlin (1920): chelicera mottled violetbrown; propeltidium violet-brown with a pale creamy light ovate area highlighted by a lighter median band extending from eye tubercle to posterior end of propeltidium; eye tubercle dark (Fig.
6); chelicera mottled dorsally and ectally coalescing anteriorly (Fig.