Paradoxides minor

Paradoxides is a genus of large to very large trilobites found throughout the world during the Mid Cambrian period. One record-breaking specimen of Paradoxides davidis is 37 cm. It has a semicircular head, free cheeks each ending with a long, narrow, recurved spine, and sickle-shaped eyes, providing almost 360° view, but only in the horizontal plane. Its elongated trunk was composed of 19-21 segments and was adorned with longish, recurved lateral spines. Its pygidium was comparatively small. Paradoxides is a characteristic Middle Cambrian trilobite of the 'Atlantic' fauna. Avalonian rocks were deposited near a small continent called Avalonia in the Paleozoic Iapetus Ocean. Avalonian beds are now in a narrow strip along the East Coast of North America, and in Europe.

The exoskeleton of Paradoxides is large to very large, relatively flat, oval to inverted egg-shaped, and about one and a half times longer than wide, with the greatest width across the genal spines. The headshield is close to semicircular with long spines developing from the corners of the cephalon. As usual in trilobites, the dorsal suture runs along the top of the eye. As in all Redlichiina, this suture runs from the back of the eye slightly outward to the rear margin of the cephalon opposite

The larval development of Paradoxides was already described by Barrande. The earliest stage is a disc with three pairs of spines on the margin. Genal spines are placed at halflength directed at about 45° outward and backward, curving slightly further backwards and almost a third of the diameter of the protaspis long. Sharply pointed intergenal spines, about 50% of the disc diameter long, are positioned at the back of the future cephalon, are straight and pointing backwards and 15° outward ...

Like in many early trilobites, the thorax of Paradoxides consists of so-called nonfulcrate segments, that allow the animal to roll, providing protection from front, rear, top, and bottom, while leaving access to the soft ventral side of the animal from each of the sides. Complete specimens of Paradoxides have been found with the free cheeks and the fused palate and lip upside down and front to back beneath the remainder of the exoskeleton. This suggests that in moulting, the body was arched above.

A number of species previously assigned to the genus Paradoxides have since been transferred to other genera.

Fossils of Paradoxides have been found in Canada, Colombia, the Czech Republic, Denmark, France, Italy, Morocco, Norway, Poland, the Russian Federation, Spain, Sweden, Turkey, the United Kingdom, and the United States.