The Burlingiidae constitute a family of trilobites of uncertain affinity, that lived during the Middle to lowest Upper Cambrian (Acadoparadoxides pinus- to Agnostus pisiformis-zone). Burlingiids have a cosmopolitan distribution, can be found in deposits that originate from outside the continental shelfs, and may have been planktonic. They are characterized by their oval shape, small size (less than 1 centimetre or 0.39 inches), proparian sutures, and non-functional articulations of the thorax. Uniquely the anterior borders of the pleura are raised, and there are between 8 and 15 thorax segments. Burlingiid trilobites have been found in Norway, Sweden, Northern Siberia, Eastern and South-eastern China, Australia (Tasmania), India (Himalayas) and the United Kingdom.