Madracis auretenra  Madracis auretenra, commonly known as the yellow finger coral or yellow pencil coral, is a colonial species of stony coral in the family Pocilloporidae. It is a fairly common species and is found in the Caribbean Sea and western Atlantic Ocean. At one time this species was not recognised, but it was split from "Madracis mirabilis" on the grounds of morphology and depth range. In 2007, Locke, Weil & Coates erected a new species of "Madracis" coral from the Caribbean Sea and named it "Madracis auretenra". They distinguished between this species and "Madracis mirabilis" (Duchassaing & Michelotti 1860), a deep-water species, on the grounds of the new species' thin-branched, dendritic structure, and its depth range (). Other characteristics that distinguished the new species from others include the presence of base skeletal structures devoid of living tissue, a fairly smooth coenosteum, a distinct line of spines between the corallites, and the absence of secondary septa in the closely spaced corallites. In erecting this species they pointed out that "Authors of many recent studies on "Madracis mirabilis sensu Wells" will need to reconsider and reconfirm the identities of their study organisms". "Madracis auretenra" forms hemispherical clumps that can be a metre or more across. Each colony is formed of densely packed, cylindrical branches with blunt, finger-like tips. In fore-reef habitats the branches are slender but in back-reef and lagoon habitats they are more robust and the clumps are larger. The hard skeletal material of which the colony is built is in most coral species covered by a thin layer of living tissue, the coenosarc. "M. auretenra" is unusual in this respect because, as the coral grows, the coenosarc progressively dies back on the lower parts of the branches leaving the skeleton bare, and only the tips of the branches are covered with living tissue. The corallites are from in diameter and have at least ten septa. This coral is bright yellow. "Madracis auretenra" is a zooxanthellate coral, housing symbiotic single-celled protists within its tissues. These provide the products of photosynthesis to the coral and use some of the coral's waste products.