The cnidae of the acrospheres of the corallimorpharian Corynactis carnea (Studer, 1878) (Cnidaria, Corallimorpharia, Corallimorphidae): composition, abundance and biometry

Corynacus carnea is a common corallimorpharian in the southwestern Atlantic Ocean, particularly in the Argentine Sea, and possesses spherical structures called acrospheres at the tips of its tentacles. characterized by particular cnidae Twelve specimens were collected to identify and measure the types of cnidae present in the acrospheres, to estimate their abundance and to study the biometry of the different types The cnidae of the acrospheres are spirocysts. holotrichs. two types of microbasic b-mastigophores and two types of microbasic p-mastigophores. Spirocysts were the most abundant type, followed by microbasic p-mastigophores and microbasic b-mastigophores: holotrichs were the least abundant The size of only the spirocysts fitted well to a normal distribution: the other types fitted to a gamma distribution. A high variability in length was observed for each type of cnida. R statistical software was employed for statistical treatments. The cnidae of the acrospheres of C carnea are compared with those of other species of the genus.