The organization of the malleolar sensory system in the solpugid, Chanbria sp.

Abstract

Five malleoli extend ventrally from the proximal segments of each hind leg of mature and immature solpugids. Each malleolus contains the dendrites of 72,000 bipolar sensory neurons with somata in a ganglion in the leg just dorsal to the malleolus. The dendrites terminate in a sensory groove which extends along the ventral edge of the sense organ. The sensory groove has a slit-like opening to the outside, suggesting that these sense organs are chemoreceptors. The malleoli also contain long processes from microvillar cells with somata in the sensory ganglion. The microvillar cell processes extend into the malleolus to the ciliary ending of the dendrites where each process has an enlarged microvillar ending which surrounds the outer segments of 15 to 22 dendrites and releases a sense secretion.