Vol. 43 No. 2, 2004

On the Invalidity of Strilloma Isaac (Copepoda: Monstrilloida): Observations from the Type Species

Eduardo Suárez-Morales* and Rebeca Gasca

El Colegio de la Frontera Sur (ECOSUR), Universidad Chetumal, Km. 2 Carr, Chetumal-Bacalar, A.P. 424. Chetumal 77000, Mexico

Eduardo Suárez-Morales and Rebeca Gasca (2004) The genus Strilloma was erected by M.J. Isaac in 1974 to contain species of Monstrilloida with 4 abdominal somites instead of 3, as in Monstrilla and Monstrillopsis, or with 2, as in Cymbasoma. This genus was described based on a single specimen of its type species, S. longa Isaac, 1974, collected 95 years ago in Florida, USA, and deposited in the Museum für Naturkunde in Berlin. Strilloma has been considered invalid by several authors, but the type species has not been reexamined since its description, and there are no concrete morphological data besides the roughly sketched original illustrations. A close examination of the holotype of S. longa allowed us to confirm that this species clearly belongs to Monstrilla. The partial suture around the genital double somite was misinterpreted as complete segmentation, a character state that is absent in the Monstrilloida; therefore, the 4 species previously assigned to Strilloma should be referred to Monstrilla, including Monstrilla scotti (Isaac, 1975), comb. nov. A complete, upgraded redescription of Monstrilla longa (comb. nov.) is presented along with a comparison to other closely related species possessing a relatively long distal antennular segment.

Key words: Marine zooplankton, Strilloma longa, Synonymization, Taxonomy.

*Correspondence: E-mail: esuarez@ecosur-qroo.mx