Presence of the Indo–Pacific genus Petrosaspongia Bergquist, 1995 (Porifera: Demospongiae) in the Atlantic with description of a new species (P. pharmamari n. sp.)

Abstract

One specimen of a keratose sponge not ascribable to any known Atlantic genus was collected by scuba diving from the shallow rocky sublittoral of El Hierro (Canary Islands). The sponge is irregularly massive and very hard in consistency, with a microconulose and unarmoured surface. The skeleton is formed by primary fibres cored with abundant foreign debris and a densely reticulate network of secondary fibres, which are strongly laminated and free of foreign debris. An irregular tertiary network formed by very thin fibres is also visible in some places. The features of the skeleton differ from those of any genus known from the Atlantic Ocean but match those of the genus Petrosaspongia Bergquist described from the Indo-Pacific and represented up to now by the species P. nigra. The Atlantic species, here described as Petrosaspongia pharmamari n. sp., differs from P. nigra by its external colour (dark brown instead of black), its consistency (a little more compressible), the greater width of the primary and secondary fibres, the higher proportion of primary fibres and the smaller diameter of meshes. The finding of a second species confirms the validity of the genus Petrosaspongia. This is the first confirmed record of the genus outside the type locality.