A peculiar calyx sponge found in the sea of Porto Cesareo (Apulia - Italy)

by Rossella Baldacconi

Calyx nicaeensis (Risso, 1826)

Phylum: Porifera
Classe: Demospongiae
Ordine: Haplosclerida
Famiglia: Phloeodictydae
Genere: Calyx

The populations of Calyx nicaeensis have suffered a great decrease, drastically reducing in several areas of the Mediterranean Sea. This endangered and rare sponge at the present is still not included in any list of protected animal. 

The populations of Calyx nicaeensis have suffered a great decrease, drastically reducing in several areas of the Mediterranean Sea. This endangered and rare sponge at the present is still not included in any list of protected animal. 
A specimen was observed in the August 2008 in the Protected Marine Area of Porto Cesareo (LE) on a coralligenous substrate at a depth of 30 m. This site is characterized by a very rich sponge assemblage where the branched sponge Axinella cannabina is the dominant species.

 

 

C. nicaensis shows a particular calyx morphology, sometimes it is characterized by an irregular and massive shape with several extensions thick 1-2 cm. The diameter of the calyx can reach 20 cm. The consistency is hard but fibrous. The colour is variable from beige to dark brown. The skeleton is constituted by a network of tiny siliceous needles (spicules) of two different size: great oxeas (100-150 μm) and small oxeas (35-80 μm).
In some site of the Eastern Mediterranean Sea, the sponge is still enough common and the old sponge fishermen use a small piece of the calyx sponge wetted in the sea water like a defogging. It is sufficient scrub the small piece on the glasses of the mask to be sure that during the immersion no fog will form inside it. 

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