Material and methods
One hundred and sixty specimens of Mycale were collected by scuba diving and snorkeling in sixty-three localities from the Pacific coast of Mexico (Fig. 1).
Fig. 1. Distribution and sample localities of Mycale-species from the Mexican Pacific Coast. Numbers refer to different species as follow: (1) Mycale (Aegogropila) magnitoxa sp. nov., (2) M. (A.) dickinsoni sp. nov., (3) M. (A.) adhaerens (Lambe, 1894), (4) M. (Carmia) contax Dickinson, 1945, (5) M. (C.) aff. magnirhaphidifera Van Soest, 1984, (6) M. (C.) cecilia de Laubenfels, 1936, (7) M. (Paresperella) psila (de Laubenfels, 1930), (8) M. (Zygomycale) ramulosa sp. nov.
Spicule preparation followed the techniques we described in previous work for light and electron microscopy (SEM). The pictures of microscleres were taken by means of a scanning electron microscope for which clean spicules were dried on a cover glass and coated with gold. Twenty five or more spicules chosen at random were measured for each of the specimens studied. The number between brackets in some descriptions is the average.
Frequency distributions of spicule size (histogram) were used to assess whether there was more than one size class. In general, a histogram is said to be multimodal if it has more than one peak.
The material studied came from the Natural History Museum of Los Angeles County (NHMLAC), where it is currently deposited the Allan Hancock Foundation (AHF) collection of sponges; material also came from the Natural History Museum of London (BMNH). The Mexican material has been deposited in the Colección de Esponjas del Pacífico Mexicano (LEB-ICML-UNAM), of the Instituto de Ciencias del Mar y Limnología, UNAM, in Mazatlán (Mexico), in the Museo Nacional de Ciencias Naturales in Madrid (Spain) (MNCN), and in the British Museum of Natural History (BMNH) (London).
Sponge-specific terms are used according to Boury-Esnault and Rützler (1997).