Published online by Cambridge University Press: 11 February 2011
Assessing and monitoring the environmental impact off Mar del Plata (38°S 57°W) led to the need to identify the cirratulid polychaetes. Cirratulids are indicators of moderately impacted areas or early indicators of organic contamination. Some subtidal sand patches affected by sewage discharge have high abundances of a new, rare and difficult to place species, such as Caulleriella trispina sp. nov. This species is characterized by having characters of three bitentaculate cirratulid genera, including three kinds of spines: unidentate, sub-bidentate and bidentate. The genera and their taxonomic characters are discussed as well as the need for monitoring and environmental assessments for correct identification. A key to the known species from the warm-temperate region of Argentine Cirratulidae is given.