Spongia (Spongia) zimocca Schmidt, 1862

Castritsi-Catharios, Jeanne, Van, Rob W. M., Kefalas, Efthimios & Vacelet, Jean, 2011, Revised description of a poorly known Mediterranean Dictyoceratid bath sponge, Spongia (Spongia) zimocca (Schmidt, 1862) (Porifera: Demospongiae: Dictyoceratida), Zootaxa 2812, pp. 41-62 : 45-50

Species Spongia (Spongia) zimocca Schmidt, 1862

LECTOTYPE: Schmidt’s specimen coded LMJG 15470 Cyprus, in the Graz Museum ( Austria).

Material examined. Representative individuals of the material studied are deposited in the Amsterdam museum ( ZMA) except one specimen, which is kept in the Athens University, and the lectotype ..

Spongia (Spongia) zimocca (between Cape Sounion and Aegina Island) ZMA POR 21430

Spongia (Spongia) zimocca ( Dodekanisos) ZMA POR 21429

Spongia (Spongia) zimocca ( Egypt) ZMA POR 21431

Spongia (Spongia) zimocca ( Libya) ZMA POR 21428

Spongia (Spongia) zimocca ( Tunisia) ZMA POR 21717

Diagnosis. Massive commercial sponge of medium size, up to 25–30 cm in width. Shape highly variable depending on depth and fishing ground, generally irregularly lobate, with more or less developed lobes. Surface non armored, finely conulose, with conules usually 200–300 µm high. Oscules simple and irregularly dispersed. Color in life black to dark gray on surface, gray inside. Texture of the skeleton fibrous, rougher than in the other Mediterranean commercial sponges. Choanosome dense, devoid of large cavities. Skeleton made of three types of spongin fibers. Primary fibers 40–50 µm in diameter, formed by the anastomoses of secondary fibers mostly near the surface conules, without pith, uncored or with a very few amount of foreign spicules. Secondary fibers in two sizes, the larger 23–40 µm in diameter forming a dense reticulation, the smaller (“pseudo-tertiary fibers”) 4.7–18.4 µm in diameter forming a more or less developed reticulation.

Geographical distribution. Eastern Mediterranean Sea, possibly also in the south-west basin.

Depth. 25 to 85 m

Substratum.: Mostly on hard substrata in the coralligenous biocoenosis. The sponge occurs also on Posidonia beds and on sandy soft bottoms.

Description of Schmidt’s lectotype. Schmidt’s sample deposited in the Graz Museum and coded LMJG 15470 Cypern has been examined. It is a massive, irregularly lobate sponge ( Fig. 6 see also Pronzato & Manconi, 2008). According to our observation, the primary fibers are devoid of inclusions. They are usually difficult to follow in the inner part of the skeleton. Near the conules, they are 40–50 µm in diameter. Their diameter is more irregular than that of the secondary fibers. They do not have a pith, but they appear less homogeneous than the secondary. The secondary fibers are 28–30 µm in maximum diameter. There are a few well-characterised thinner secondary fibers (“pseudo-tertiary fibers”), 10–15 µm in diameter, possibly with intermediaries with the secondary.

Description of our specimens.

External morphology. S. zimocca or Leather sponge or Tsimoucha is present in two forms, A from Egypt, Libya and Tunisia mainly, B1 and B2 from Greek seas mainly.

A ( Figs. 2–6 ). Compact sponge, with flat to slightly lobose upper surface (directly opposite to the base), where large oscula are observed (size range 4.2–5.4 mm). These oscula appear on the top of lobes, the latter located closely together without any empty spaces in between. Conversely on all other surfaces, and more specifically at the circumference of the base and up to the upper surface, filamentous projections ( Fig.28 ) are observed. These protrusions connect to the main body and each has a large osculum at their upper surface. This particular form is found in Tunisia, Libya, and Egypt.

B This form includes two sub-forms. The first one B1, ( Figs.7–8 ), which can be found in shallow depths, exhibits a compact form with numerous protrusions connected at their base while the upper extremities are free. In comparison to form A, form B has smaller lobes and oscula. In this form we can easily observe two categories of oscula, i.e. small (size range 1.7–2.5 mm) and large (size range 3.5–4.5 mm). This form, especially that of ZMA POR 21430 ( Fig.7 ), is morphologically identical to Schmidt’s lectotype from Cyprus ( Fig. 8 ).

The second sub-form B2 ( Fig.9–10 ) can be found in deeper waters and is usually fished by dredge-trawlers. The lobed formations are well developed with 1/4 or 1/5 of their length remaining attached to the sponge body ( Fig. 11 ). This form is in good accordance with the description of Euspongia zimocca var. adjimensis Topsent (1924) , who mentions that according to Duboscq “this sponge is often loboid with lobes ending to one or different levels, with big gaps between them in a part or along all their length”. Their free surface is bilateral, symmetrical or not. Oscula are not necessarily found on the summits of the lobes but more or less on the side, a little underneath the round apex. From the osculum starts a linear channel visible through naked eye in the dry samples, as described by Schmidt 1862 ( Fig. 12 ).

In Table 1 all forms of S. zimocca are shown (A, Β1 & Β2) collected by the divers during the sampling trips as well as the corresponding geographical distribution. Of 3,783 sponges harvested from Libya, 302 were S. zimocca in depths between 20–45 m, and of these, 241 individuals were of form A and 61 of form B1.

AREA FORM A FORM B 1 FORM B 2 The external color of S. zimocca in life depends on its habitat. Like many sponges, it is lighter coloured in shaded habitats, and called “drossitis” by divers. In Posidonia beds, it is black, like the other commercial sponge species ( Fig.13–14 ). As soon as the sponge is transferred to the boat and prior to any kind of treatment, a cut of the sponge appears light gray or light brown (rusty brown), while the channels leading to the oscula are dark gray (pers. comm., Manolis Saroukos).

The conules are thin, dense, arranged irregularly and their surface carries deep corrugations, parallel from the base to the top of the conule ( Fig 15 ). In samples taken from Greek waters the conules have the following mean values (preliminary results): height = 200–300 μm, diameter of the base = 150–250 μm, diameter of the top = 50– 100 μm. ( Table 2 ).

Several extraneous structures are attached to the pinacodermal membrane. Primary fibers form conules on the surface, which they frequently pierce ( Fig. 28 ), surrounded by a dense mesh of secondary fibers ( Figs. 16 , 17 ).

Internal structure. Primary fibers ( Figs 18, 19 ) are abundant near the surface, with very rare foreign inclusions, with a diameter of about 40–50 μm. The secondary fibers ( Figs 20–23 ) are smooth and uncored. Two size classes were found (values of their diameter are shown in Table 3). The secondary fibers with a significantly smaller diameter, that we call here “pseudo-tertiary fibers” ( Figs 24–27 ) exist in abundance in all our samples. According to our knowledge this taxonomic character has not been recorded for this Mediterranean species of Spongia .

T ABLE 3. Spongia zimocca . Diameter of the secondary and pseudo-tertiary fibers on different positions. (samples from the

market and the specimen deposited in Graz Museum).

The choanocyte chambers are spherical with a diameter of 18–22 μm ( Fig 29 ). The choanocytes are pear shaped with a diameter of 5.6 μm. The cells carry on their upper outer side a collar formed by microvilli and a welldeveloped flagellum (approximate length 3 μm).

Distribution and biogeography. Data gathered from sampling trips: 1223 individual sponges were collected by the hookah method and 114 by the gagava method, 1337 individual sponges were collected in total, S. zimocca representing 0.8% of this total and was found in all fishing grounds except Evia Island and Ionian Sea, at depths varying between 25 and 87.5 m,. The records of abiotic parameters, the depth and the type of substratum are given in Table 4. In Table 5 we provide a summary of the results obtained from the measurements of our samples (biometrical data correlated to the sampling stations and the depth of collection).

SN AREA TESU TEBO SASU SABO PHSU PHBO DOSU DOBO TURB DEPTH SUB

o C o C 0/0 0 0/0 0 m m

1 A 22.5 22.0 40 40 8.0 7.9 7.2 6.0 30 70 a

2 B 23.5 22.0 41 39 7.9 7.9 6.2 6.6 55 b 3 C 22.0 21.3 40 39 8.0 8.1 6.8 6.3 40 80 c 4 C 21.0 21.5 40 39 8.1 8.0 7.0 6.5 39 55 d 5 C 23.5 23.0 42 41 8.1 8.1 7.2 6.9 27 25 e 6 D 22.0 22.0 40 40 7.9 7.9 6.8 6.6 27 87 f

SN: serial number, AREA: geographical area, TESU: temperature of surface, TEBO: temperature of bottom, SASU: salinity of surface, SABO: salinity of bottom, PHSU: Ph of surface. PHBO: Ph of bottom, DOSU: dissolved oxygen of surface, DOBO: dissolved oxygen of bottom, TURB: turbidity, DEPTH: depth at which the samples were collected, SUB: type of substratum (see below). A: Creta island, B: Cyclades complex of islands, C: Dodekanissos complex of islands, D: Samos island, I: Gaidouronissi island, II: Naxos – Ios islands, III: Kalymnos island (Emporio), IV: Kalymnos island (Vathi), V: Tilos – Antitilos islands, VI: Vathi (Aghia Paraskevi). a: littoral zone: hard substratum / infralittoral and circalittoral: among calcareous algae, coralligenous biocoenosis and thin grain sand. b: infralittoral and circalittoral zone: calcareous algae, thick grain sand and coralligenous biocoenosis. c: infralittoral zone: biocoenosis of fine, well sorted, sand – anthropogenous interference / circalittoral zone: hard substratum, coralligenous biocoenosis. d: infralittoral and circalittoral zone among calcareous algae and coralligenous biocoenosis. e: infralittoral zone: Posidonia beds and sandy soft bottoms, precoralligenous biocoenosis / circalittoral zone: coralligenous biocoenosis. f: infralittoral and circalittoral zone: hard bottom, calcareous algae and coralligenous biocoenosis 70 17 10 10 50 NAXOS-IOS 55 15 11 13 37

55 16 10 8 42 Data obtained through the fleet (diver-key forms): The divers collected 21570 individual bath sponges during the period mid-July to mid-October of 1993 and 1994 (15 boats and 45 divers). The distribution of S. zimocca (5% of the total catch) is given in Table 6. The distribution by shape and size of S. zimocca per area and depth is included in Table 7 .

LIBYA CRETE DODEKANISSA CYCLADES LAKONIA IONIAN SEA REST AEGIAN 302 267 345 127 0 0 37 8.0% 2.4% 12.7% 7.1% 0% 0% 6.3%

Total catch = 1078 individuals, i.e. S. zimocca represents 5% of the total catch CRETE DODEKANISSOS

CYCLADES

Depth 1–20 m 21–40 m 41–60 m 61–80 m 81–100 m 101–140 m AS: shape A, size small / AM: shape A, size medium / AL: shape A, size large / TA: total A. BS: shape B, size small / BM: shape B, size medium / BL: shape B, size large / TB: total B. GT: grand total.

The sponge fishing fleet did not find any S. zimocca in the Ionian Sea and in the Lakonia prefecture, at depths 1– 40 m. In 2008, the Kalymnian divers harvested the following quantities of sponges in the areas previously mentioned:

- H. communis : 2,000 kg, sizes 12.5–51 cm

- S. o. officinalis : 1,700 kg, sizes 12.5–30.5 cm - S. o. mollissima : 300 kg, sizes 12.5–38 cm

- S. zimocca and S. lamella were not harvested

Organic content of the fiber mass and skeletal density. Our results for organic content on samples from typical specimens of S. zimocca are given in Table 8. Comparative results for skeletal density of four other Mediterranean commercial sponges are presented in Table 9.

S. zimocca S. o. mollissima S.o. officinalis S. lamella H. communis

Dry Weight/Wet Weight Average 93.32 92.18 92.27 94.06 93.34 0/0 SD 1.21 1.23 1.00 0.45 0.83 Inorganic Material/Dry Average 9.17 14.23 11.38 30.10 16.15 Weight 0/0 SD 2.28 5.22 4.36 10.04 5.60 Organic Material/Dry Average 90.83 85.77 88.62 69.90 83.85 Weight 0/0 SD 2.28 5.22 4.36 10.04 5.60 Inorganic Material/ Average 10.15 16.98 13.07 44.55 19.72 Organic Material 0/0 SD 2.79 7.54 5.85 20.77 8.11 Nr Of Samples 6 7 5 2 7 TABLE 9. Skeletal Density (gr cm -3), statistical data.

Species N Mean Value Mean Deviation Typical Deviation S. zimocca 7 0.053707 0.006273 0.007902 S. o. offcinalis 4 0.055743 0.003183 0.004354 S. o. mollissima 9 0.049945 0.009146 0.011433 S . lamella 7 0.066438 0.015211 0.022291 H. communis 7 0.044999 0.022848 0.034300 Tensile strength. Castritsi-Catharios et al. (2007) suggest that both the tensile strength and the elasticity can be used as two objective criteria for the evaluation of the quality and commercial value of commercial sponges. These criteria could also provide additional taxonomic characters for the distinction of ill-defined species. Preliminary results for the tensile strength and elongation of all five Mediterranean commercial species of sponges are presented in Table 10.

TABLE 10. Preliminary results for the tensile strength (in Kg cm -2) of commercial sponges.

Species Nr. of specimens Mean Value Mean Deviation

Maximum Value Elongation (%) Maximum Value Elongation (%)

Hippospongia communis 7 1.3129 27.1000 0.3869 6.0286 Spongia lamella 6 4.0079 21.0167 2.0248 1.9889 Spongia . zimocca 6 1.8476 17.3000 0.2879 3.3333 Spongia o. officinalis 9 2.6802 20.7667 0.9609 3.6815 Spongia o. mollissima 5 2.2360 24.9400 0.5021 4.2080

Figures

FIGURE 29. Spongia zimocca (collected from Naxos Island at 60 m depth). Spherical choanocyte chamber 20 μm in diameter, choanocyte cells with characteristic shape and the collar of microvilli surrounding the flagellum.

FIGURES 4 – 6. Spongia zimocca. 4, Form A sponges harvested from Libya. 5, Characteristic specimen from Tunisia (upper surface). 6, Characteristic specimen from Tunisia (surface of attachment).

FIGURES 1 – 3. Spongia zimocca. 1, Map showing in red the species’ distribution in the Mediterranean Sea (Greece: Aegean Sea, Dodekanissos, Cyclades, Crete, Ionian Sea, Laconia / Egypt / Libya / Tunisia). 2, Compact sponge from Libya, with flat to slightly lobose upper surface. 3, Specimen harvested from Tunisia.

FIGURES 27 – 28. Spongia zimocca. 27, Secondary and pseudo-tertiary fibers of a specimen from Aegean Sea deep waters (60 – 70 m). 28, Primary fiber protruding from the conule of a sponge harvested at Anafi Island in 2009.

FIGURES 7 – 9. Spongia zimocca. 7, Compact form found between Cape Sounion and Aegina Island. 8, Specimen LMJG 15470 from the Graz Museum collection. 9, Sponges harvested by gagava trawler from Posidonia beds.

FIGURES 10 – 13. Spongia zimocca. 10, Sponge from deep waters of Dodekanissos. 11, Well developed lobes, ¾ of their length being free. 12, Linear channel starting from osculum, as described by Schmidt (1862). 13, Sponge just harvested from Agathonissi Island (ca. 60 m depth.).

FIGURES 14 – 16. Spongia zimocca. 14, Sponge just harvested from Astipalea Island (ca. 18 m depth.). 15, SEM of conules with pinacodermal membrane carrying many foreign structures. 16, Primary fiber surrounded by a dense network of secondary fibers in a specimen from Libya.

FIGURES 17 – 20. Spongia zimocca. 17, End of primary fibers in a Tunisian specimen. 18, Primary and secondary fibers from a Libyan sponge. 19, Primary and secondary fibers from a Tunisian specimen. 20, Secondary fiber from a sponge collected near Agathonissi, at 60 m depth.

FIGURES 21 – 26. Spongia zimocca. 21, Secondary fibers of a sample collected from Egypt. 22, Secondary fibers from a specimen obtained from shallow depths between Cape Sounion and Aegina Island. 23, Secondary fibers of a sample collected at great depth from the Aegean Sea. 24, Pseudo-tertiary fibers of a specimen collected from Libya. 25, Pseudo-tertiary fibers from a North African specimen. 26, Pseudo-tertiary fibers of a sample collected at great depth from the Aegean Sea.

Tables

TABLE 2. Characteristics of the conules of the commercial species of sponges (preliminary results).

Species Height in μm Nr. of specimens / nr. of replicates	Diameter of the base in μm	Diameter of the top Surface of the conule in μm (External morphology)
S. zimocca 5/3 200–300	150–250	50–100 Deep corrugations, parallel, from the base to the top of the conule
S. o. mollissima 4/3 150–200	200–250	50–100 Leaf like structure
S. o. officinalis 3/3 300–600	400–600	100–200 Thin grained structure or smooth
S. lamella 3/3 200–250	200–2500	120 Pinacoderm-like with many surfaces.
H. communis 4/3 800–1200	700–800	200–300 Pinacoderm-like, which is not differentiated up to the top. Thin, irregular corrugations

TABLE 5. S. zimocca. Sampling stations, collection depths and dimensions of specimens. SAMPLING DEPTH LENGTH WIDTH HEIGHT CIRCUMFERENCE AREA m cm cm cm cm CRETE 70 60 60 25 160 Gaidouronissi 70 28 19 10 78

KALYMNOS 80 Emporios-Telendos 80	5 13	10 10	7 10	24 31
KALYMNOS 80 Vathis	5	10	7	24
TILOS-ANTITILOS 25	14	11	10	40
25	14	11	9	34
SAMOS 82 Vathis-Agia Paraskevi	20	16	11	47
MIN 25	5	10	7	24
MAX 82	60	60	25	160
AVERAGE 62.9	18.8	16.2	10.9	51.5
STDEV 20.9	15.1	14.8	5	38.9

TABLE 7. Frequency of appearance and depths at which S. zimocca was collected by the fishing fleet.

Depth	1–20 m	21–40 m	41–60 m	1–20 m	21–40 m	41–60 m	61–80 m	81–100 m
Shape BS And BM Size BL TB AS	8 86 26 120 10	30 0 0 30 0	0 0 0 0 0	5 26 32 63 0	2 57 43 102 19	2 23 7 32 0	0 13 0 13 0	0 3 5 8 0
AM	76	0	0	0	65	3	2	0
AL TA GT	31 117 237	0 0 30	0 0 0	0 0 63	63 120 222	2 5 37	0 2 15	0 0 8
continued.