Harvestman Anatomy - Prosoma

Prosoma

The frontal portion of the body contains the main part of the centralized nervous system, the feeding organs and defensive glands, and the legs. The upper side is covered by a sclerotized carapace, which is formed by the fused tergites of the six appendage-bearing somites. The feeding apparatus is called the stomotheca. It is formed by extensions from the pedipalps and the first leg pair. The ocularium, an elevated mound placed in the middle of the carapace, usually contains two simple eyes, although they are lacking in some species. It can be smooth or armed with small or large spines. In some Dyspnoi the eyes are located on projections that form a hood covering the mouthparts.

On the sides of the prosoma there are defensive glands called ozopores, which in Cyphophthalmi open on the tip of an elevated cone, the ozophore. The prosomal muscles attach to the endosternite, a horizontal sheet of connective tissue similar to cartilage that acts as an internal skeleton. In some harvestmen (Phalangium, Odiellus and Leiobunum) it contains calcium deposits. The endosternite is U-shaped, with the arms facing forward and embracing the ganglion above the esophagus.

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