The genus Phragmatopoma included, until now, only four valid species with distributions in Eastern Pacific and Western Atlantic. Since most taxonomic studies of Phragmatopoma include poor and uninformative descriptions, the aim of this work was to expand previous descriptions of the sabellariids of Phragmatopoma genus from Tropical America. Sabellariids from two Mexican collections, the Reference Collection of El Colegio de la Frontera Sur, Chetumal, and Laboratorio de Sistemática de Invertebrados Marinos (LABSIM), Universidad del Mar, Puerto Ángel, were revised. Six hundred sixty-six specimens were revised, and eight species were identified. Three new species are proposed: Phragmatopoma balbinae n. sp., from southern Mexican Pacific, P. carlosi n. sp., from northern Mexican Pacific and P. villalobosi n. sp., from Pacific of Costa Rica. Another morphospecies, Phragmatopoma sp., from Pacific of Costa Rica is characterized; however, it is only one specimen. Two species, Phragmatopoma digitata and P. peruensis, previously buried in the synonyms of P. virgini (type locality: Straits of Magellan, Chile), are considered as valid species. Also, new records of P. californica and P. caudata were made in Baja California and Veracruz, respectively. Additionally, the use of standard terminology for the description of opercular paleae and chaetae is proposed.
New records and combinations of Lyrella (Bacillariophyceae: Lyrellales) from a protected coastal lagoon of the northwestern Mexican Pacific
