THE MAGELONIDAE FROM THE MEXICAN PACIFIC WITH THE DESCRIPTION OF THREE NEW SPECIES OF MAGELONA
González-Ortiz, L.; Hernández-Alcántara, P. & Solís-Weiss, V.
Laboratorio de Ecología Costera, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México. Apdo. Postal 70-305. México D.F., 04510, Mexico
In this study we analize 604 specimens from the family Magelonidae collected during extensive surveys made along the continental shelf of the Pacific coasts of Mexico (Gulf of California, Gulf of Tehuantepec, and shores of the state of Guerrero). The study area covers latitudes 15° 35´N to 31° 20´N and longitudes 94° 00´W to 114° 23´W. Previous records of magelonids in the Mexican Pacific include Magelona californica, M. pitelkai, M. pacifica and M. sacculata, basically distributed in the continental shelf, although M. californica has been recorded down to 1458 m. In this study, all those species were found, except M. sacculata and their distribution are discussed examining mainly the influence of latitude, type of sediment and depth. In addition, three new species are herein described and illustrated and their affinities to related species in the genus Magelona discussed. The first is characterized by the presence of thick, unidentate noto- and neuropodial hooks in some abdominal anterior setigers. In the second, frontal horns and well developed crenulations, middorsal lobes and tridentate abdominal hooks are present. The third is the only species in the genus with distally crenulated lateral lamellae. A taxonomic reversible key is provided for species found in the Mexican Pacific.