Figure 1. Weapon polymorphism in Pantopsalis cheliferoides.

Males were assigned to three weapon morphs: (a) long-slender, (b) short-broad, or (c) a short-slender. (d) Chelicera length showed dimorphism. (e) The scaling relationship between chelicera length and body size revealed two morphs (open circles <95% confidence of morph assignment): a long-slender morph (alpha, green dots, black line) and a short-broad morph (beta, purple dots, dashed line). However, when these data are plotted against chelicera width (f), the beta (purple) morph is split into two groups, suggesting that one measurement of chelicera size does not adequately capture the variation in this trait. (g) Chelicera width showed trimorphism with three skew-normal distributions, revealing a third, short-slender morph (gamma, blue dots, dotted line) that previously was grouped with the short-broad morph (h). (i) These three morphs plotted on to a scaling relationship of chelicera length demonstrates a split between long-slender (alpha, green dots), short-broad (beta, purple dots) and short-slender (gamma, blue dots) males.