Geodia cydonium

Jameson, 1811

Species Overview

Geodia cydonium Jameson, 1811 is a greyish white, somewhat flattened, rounded sponge, with an irregular, largely smooth, but often encrusted surface. Consistency hard.

Taxonomic Description

Colour: White-grey exterior, orange interior.
Shape, size, surface and consistency: Subspherical, somewhat flattened, 8-15 cm in diameter. Surface irregular, generally hispid, but here and there smooth, encrusted by shells and pebbles. Oscules and ostia grouped in cribral areas. Oscules 1.5-2 mm in diameter. Consistency hard but fragile.
Spicules: (Geodia cydonium spics) Megascleres : Huge oxeas, fusiform, occasionally modified to styles and strongyles: 850-4000 x 15-50 µm; cortical oxeas: 250-600 x 7-10 µm; orthotriaenes: rhabd 420-3000 x 6-20 µm, cladi 40-160 x 10-40 µm; protriaenes: 1200-6000 x 60-100 µm; anatriaenes: rhabds 420-6000 x 6-20 µm, cladi 40-160 x 10-40 µm; mesodiaenes and mesotriaenes: 700-4600 x 6-20 µm, cladi 45-160 x 6-20 µm.
Microscleres : Sterrasters, globular: 30-70 µm in diameter; chiasters with few cylindrical rays: 10-20 µm; spherasters: 10-20 µm; oxyasters: 15-40 µm.
Skeleton: Ectosome : a cortex clearly distinct from the choanosome, 2 mm in thickness. Spicules are microscleres and microxeas, and protruding protriaenes causing the hispidation; the cortex is carried by the cladomes of subcortical triaenes. Choanosome : radial arrangement of oxeas and triaenes, with scattered oxyasters.
Ecology: Pebble bottoms at 80-94 m.
Distribution: Roscoff, Norway; Mediterranean.
Etymology: Kydonia (Greek) is a city on ancient Crete.
Type specimen information: No data.

Remarks

Geodia barretti is a similar species, but differs from the present by its possession of dichotriaenes. It occurs predominantly in northern waters and reaches much larger size.
Source: Uriz, 1981.