New coral reef boring sponges (Hadromerida: Clionaidae) from the Mexican Pacific Ocean

Abstract

Two alpha growth form species of boring sponges, Clionapocillopora sp. nov. and Cliona mucronata are described from coral reefs in the Mexican Pacific Ocean. Clionapocillopora sp. nov. is a light brown sponge containing tylostyles that measure 146×5 μm. Tylostyles are generally curved and have a globular or mucronated head, sometimes placed at some distance from the proximal end. In addition, straight, short and thick tylostrongyles and centrotylote oxea occasionally appear. Cliona mucronata is reported for the first time in the eastern Pacific Ocean. It is a red to red-orange sponge with two types of tylostyles, long and slender tylostyles, and short ensiform tylostyles. Both species have been found exclusively excavating corals of the genus Pocillopora. The boring activity of Clionapocillopora sp. nov. produces a network of galleries with mainly rectangular or polygonal chambers measuring from 0.7 to 2.4 mm in diameter, and C. mucronata produces a network of reticulate galleries with irregularly spherical or ovoid chambers 1.14×0.67 mm in diameter.