Numerous Early Cambrian corals or “coralomorphs,” as they are often classified, are recorded from North America, Australia, and Siberia. A new Early Cambrian coral, Harklessia yuenglingensis n. gen. and sp., is found in conjunction with archaeocyathan-microbial reefs in Esmeralda County, southwestern Nevada. The coral-bearing reefs are within quartzic, trilobite-rich packstone beds in the upper portion of the Harkless Formation (Bonnia–Olenellus Zone). Coralla are constructed by subpolygonal to polygonal, cerioid, close-packed corallite tubes. Coralla average 12 cm in height by 18 cm in diameter with individual corallite tubes ranging from 1.2 to 3.2 mm in diameter. Corallites are greater than 25 mm in length. Septa and tabulae are not present.
Many of the Early Cambrian corals previously described have attributes of the class Anthozoa and subclass Zoantharia, with some specific similarities to tabulate corals. Harklessia yuenglingensis is placed confidently within the class Anthozoa, subclass Zoantharia because its morphological characteristics indicate an affinity to true corals, but whether H. yuenglingensis is a tabulate coral remains uncertain.