Avalonian rocks were deposited near a small continent called Avalonia in the Paleozoic Iapetus Ocean.

The preocular sections of the facial suture follows a slight S-curve and intersect the anterior cephalic margin in front of the eye.

Hypostoma in some species is fused with the rostral plate, e.g. in Paradoxides davidis,[2] a character that distinguishes the genus from all other trilobites, except in some Cambrian Corynexochida such as Oryctocephalus and Fieldaspis.

Thorax consists of 19–21 segments; axis about as wide as each of the pleurae, excluding pleural spines which curve backwards and slightly increase in length towards posterior.

In moulting, the body was arched above the substrate, with the anterior border at the front and posterior pleural spines dug into sediment.

Stretching the body would then result in rupturing the sutures in the cephalon and flipping off the librigenae including the rostral-hypostomal plate.

[4] A number of species previously assigned to the genus Paradoxides have since been transferred to other genera:[5] Fossils of Paradoxides have been found in Canada (New Brunswick, Newfoundland and Labrador), Colombia (Duda Formation, El Dorado, Meta),[8] the Czech Republic, Denmark, France, Italy, Morocco, Norway, Poland, the Russian Federation, Spain, Sweden, Turkey, the United Kingdom, and the United States (Alaska, Massachusetts, South Carolina).