Especies de dinoflagelados atecados (Dinophyta) de la costa de Chiapas, sur del Pacífico Mexicano

Abstract

Athecate dinoflagellates have been poorly studied in the plankton of Mexican marine waters, mainly because of their fragility, as they may become deformed using nets and strong fixatives. However, their biodiversity and ecological role might be important in the planktonic realm. As part of routine phytoplankton monitoring in the Chiapas coasts, Mexico, in the southern Mexican Pacific, samples were obtained during 2009 by net (20 μm mesh) in vertical hauls (up to 15 m), fixed with Lugol's solution and studied by light microscope (bright field and phase contrast). Athecate dinoflagellates species were identified using morphological characters such as shape and size, nucleus position, chloroplasts number and position, and particular characters ('arms', 'carina', etc.). Twenty-seven species were documented to be present in the study area, with 3 species considered to be new records for the Mexican Pacific Ocean: Cochlodinium pulchellum, Karenia bicuneiformis (= K. bidigitata) and K. papilionacea. Few species studied here have historically been reported as 'bloomforming' species in other parts of the Mexican Pacific. It is clear that more studies should be systematically done to assess the present biodiversity of these dinoflagellates groups in Mexican waters.