(Keller, 1879)
Species Overview
Acervochalina fertilis (Keller, 1879) is a light pinkish-or purple-brown, massively encrusting, lobate, soft sponge, which has been recorded several times in the Mediterranean-Atlantic area. It differs from other species of Acervochalina in having a thick basis and in the possession of robust oxeas (microscopic examination).
Taxonomic Description
Colour: Light purple brown in life, purplish grey-brown in alcohol.
Shape, size, surface and consistency: Massively encrusting, with irregular lobes; size up to 10 x 2.5 x 1.5 cm; oscules flush, 2-3 mm in diameter; surface hispid; consistency, soft, limp, highly compressible.
Spicules: Short, robust, gradually but sharply pointed oxeas: 75-120 x 3-10 µm.
Skeleton: (Acervochalina fertilis skel) Ectosomal : spicules and fibre terminations pierce the organic dermis, no special ectosomal skeleton. Choanosomal : the skeleton is a loosely arranged open reticulation of paucispicular primary lines (2-6 spicules in cross section) and interconnecting uni-paucispicular lines (1-4 spicules in cross section), normally of more than one spicule in length. All skeletal lines are enveloped in moderate quantities of spongin.
Reproduction: Embryos (and thus presumably larvae) are orange and bear juvenile spicules (Griessinger, 1971:# Acervochalina fertilis skel2).
Ecology: On rocks in the littoral and shallow sublittoral; in estuarine areas.
Distribution: Mediterranean, Azores, Canary Islands.
Etymology: Fertilis (Latin) = fertile, referring to the copious production of larvae.
Type specimen information: Not so far identified. Keller's material supposedly is in the Berlin Museum.
Remarks
Topsent (1938) synonymized this species with Chalinula renieroides Schmidt (1868), the type species of the genus Chalinula Schmidt (1868), but we agree with Griessinger (1971), that this is incorrect. Schmidt's description and also Topsent's redescription make it clear that this species very probably does not have the characteristic interconnecting lines of more than one spicule in length. The species remains ill-known but probably conforms to Haliclona . Griessinger (1971) and Boury-Esnault and Lopez (1985) continue to use the genus name Chalinula for fertilis and limbata , but this is incorrect in view of the characters described in C . renieroides . Acervochalina Ridley (1884) was erected for Spongia limbata Montagu (1818) and thus constitutes the earliest available replacement name. Van Soest's (1980) synonymization of Acervochalina and Haliclona is refuted.
The present species was recently collected on Tenerife (Playa de las Teresitas, 2m, specimen in the collections of the Zoologisch Museum Amsterdam, reg. no. POR. 5191); its life colour was purple-brown.
Lévi (1959), described from West Africa "Chalinula " parasimulans , recently also found on Tenerife (Cruz, pers. comm.), and Boury-Esnault and Lopes (1985) described "Chalinula " nigra from the Azores. Both are related but different species with much darker live colour.
A twin species of A . fertilis seems to be Acervochalina molitba (De Laubenfels, 1950), from the West Indian region (cf. Van Soest, 1980); differences are the considerably thinner spicules in the latter.
Source: De Weerdt and Van Soest, 1986.