Pione mazatlanensis Hancock, 1867

Material examined. ICMYL.Pma.84.R, ICMYL.Pma87.R: Playa Matapalo, 3 m, 20.XII.2012, coll. and det. Cristian Pacheco Solano.

External morphology. Endolithic sponge in alpha morphology. No data available on papillae. Live color ochre.

Excavation. Not assessed.

Spicules. Megascleres slightly curved tylostyles. Microscleres smooth or microspined, curved oxeas with or without cetrotyle and helical, microspined microrhabds in two shapes: short and straight, and long and helical (Fig.

29). Tylotyle dimensions: 152–215 µm (x̅ =198.9, σ=26.6) x 2.5–5 µm (x̅ =3.3, σ=0.9). Oxea dimensions: 52.5–110 µm (x̅ =81.4, σ=14.5) x 2.5–5 µm (x̅ =3.6, σ=0.8). Microrhabd dimensions: 10–15 µm (x̅ =11.9, σ=1.9) x 1 –2.5 µm (x̅ =1.8, σ=0.4).

Ecology. Found in dead pocilloporid corals at 3 m depth.

Distribution and previous records. The first report was from Mazatlan, Mexico (Hancock 1867). Carballo et al. (2004) found the species in the Mexican Pacific again, ranging from the north (Sonora) to the south (Oaxaca). P. mazatlanensis has not previously been located outside Mexican waters, and this is the first record for Costa Rica and Central America (Fig. 30).

Remarks. The microrhabdes, especially those long and helical microrhabdes are the characteristics that allow identify the species and distinguish from other Pione . The dimensions of the spicules from the specimens we reviewed, are similar to those described from the Mexican Pacific (Carballo et al. 2004).