Sexual dimorphism in Opiliones is extremely varied and may be apparent in almost all body parts, playing complex and poorly understood roles.
The saddle in Phalangioidea is often much sharper in females, while in males it is more indistinct.
In many Eupnoi and Laniatores, color dimorphism may be so intense that often different sexes ended up described as different species. A striking example is the Brazilian Mitobatinae Metamitobates squalidus (Perty, 1833), in which the female is green with red tints, while the male is mostly yellow.
In some species of Gonyleptoidea the male has greatly developed ocularium, which causes the carapace to grow backwards deforming area I, while in females the ocularium is considerably smaller and the area I is not squeezed.
But there are other kinds of dimorphism in the chelicerae, for example spines and protuberances on bulla or most commonly on the cheliceral hand.
Pedipalps may be much elongate (either subtly or immensely) in males only (Cranaidae), or immensely stout, keeled in males (Cranaidae).
In Podoctidae, while female pedipalps are ordinary cylindrical, those of males may assume bizarre forms, such as a bottle shape.
In some species of Phalangiinae (e.g., in genera Cristina, Phalangium), males may have immensely stout front legs. This is much rarer in Laniatores, where an undescribed Paratricommatus from Brazil shows this feature.
Tarsus of leg IEdit
In most Gonyleptoidea, males have thickened glandular basitarsomeres in leg I. More notably so in the males of Manaosbiidae, in which basitarsomeres are fused into a very large spindle. This also occurs in some species of Cosmetidae.
Coxa of leg IVEdit
A well-developed apophysis is a trademark of the Gonyleptidae males, often forming a pincer with a matching apophysis of trochanter IV.
Trochanter of leg IVEdit
Femur of leg IVEdit
Tibia of leg IVEdit