sigma-derived (meniscoid) microsclere with a curved shaft and recurved alas at each end.
The following types exist (numbers refer to picture "isochelae SEM" :
-acanthancora (1)
-anchorate chela (2)
-anisochela (3, 4)
-arcuate chela (5,6)
-biplacochela (7)
-bipocilla (8)
-birotula (14)
-canonochela (17)
-cleistochela (18, 19)
-coelodischela (9)
-croca (12)
-isochela (1,2,5,6,10,11,19,21)
-palmate chela (3,4,10,11,19)
-placochela (15)
-spatuliferous chela (2)
-sphaerancora (13)
-spurred chela (4)
-tetrapocillon (16)
-thaumatochela (no picture)
-unguiferate chela (21)

Alternative forms for chela : chelae, chelas.