Monotypic prehistoric Bilateria genera

Pikaia gracilens is an extinct, primitive chordate marine animal known from the Middle Cambrian Burgess Shale of British Columbia. Described in 1911 by Charles Doolittle Walcott as an annelid, and in 1979 by Harry B. Whittington and Simon Conway Morris as a chordate, it became "the most famous early chordate fossil", or "famously known as the earliest described Cambrian chordate". It is estimated to have lived during the latter period of the Cambrian explosion. Since its initial discovery, more than a hundred specimens have been recovered.

Tullimonstrum, colloquially known as the Tully monster or sometimes '''Tully's monster, is an extinct genus of soft-bodied bilaterian marine animal that lived in shallow tropical coastal waters of muddy estuaries during the Pennsylvanian, about 310 million years ago. A single species, T. gregarium', is known. Examples of Tullimonstrum'' have been found only in sediments deposited far from the palaeocoast (formally termed the Essex biota), in the Mazon Creek fossil beds of Illinois, United States. Its classification has been the subject of controversy, and interpretations of the fossil have lik

Yunnanozoon lividum (from Yunnan, and Ancient Greek ζῷον (zôion), meaning "animal", with specific name coming from Latin lividum; (lead-coloured), referring to preserved colour of specimens) is an extinct species of bilaterian animal from the Lower Cambrian Chengjiang biota of Yunnan province, China. Its affinities have long been the subject of controversy.

Yuyuanozoon magnificissimi, from the Cambrian Stage 3 Chengjiang lagerstatte, is the largest known vetulicolian, an extinct species of marine animal, with specimens up to 20 cm in length compared to 5–14 cm for other vetulicolian species.

Burykhia hunti is an Ediacaran fossil from the White Sea region of Russia dating to . It is considered of possibly ascidian affinity, due to the sac-like morphology and a series of distinctly perforated bands reminiscent of a tunicate pharynx. If B. hunti is a tunicate, it could be the oldest ascidian fossil known as of its publication in 2012. It is also possibly related to the slightly younger Ausia, another putative ascidian from the Vendian biota in Namibia.

Skeemella is a genus of elongate animal from the Middle Cambrian Wheeler Shale and Marjum lagerstätte of Utah. It has been classified with the banffozoan vetulicolians.

extinct genus of animals