Hymedesmia (Hymedesmia) anatoliensis, Gözcelioğlu & Soest & Alvarez & Konuklugil, 2015

Gözcelioğlu, Bülent, Soest, Rob Van, Alvarez, Belinda & Konuklugil, Belma, 2015, New species of sponges (Porifera, Demospongiae) from the Turkish coast, Turkish Journal of Zoology 39 (4), pp. 555-559 : 557-559

Hymedesmia (Hymedesmia) anatoliensis sp. nov. ( Figure 2 )

Material examined:

Holotype RMNH Por. 7465, İbrice Harbor (Edirne), 40°36′8″N, 26°32′33″E, Saros Bay , northern Aegean Sea, Turkey, coll. field number Ibrice 13.

Description. Thin encrustation on a limestone conglomerate consisting of dead oysters, serpulid tubes, and massive bryozoans. The available material consists of a larger limestone fragment, 2 × 2 × 0.5 cm in size, and several smaller pieces. The sponge coating of less than 1 mm in thickness grew on the surface and insinuated into holes and crevices, but is lacking from the upper surface of the limestone fragment. The color is reddish-yellow to brown in dried condition and this persists in alcohol, indicating that the live color may be similar. The sponge surface is microhispidated. Consistency is fragile.

Skeleton. Hymedesmioid, with acanthostyles erect on the substrate with the heads embedded in a basal spongin plate. Tornotes are arranged in thin, lax bundles of 3 or 4 in cross-section, at right angles to the substrate. They fan out at the surface and support the dermal membrane, which is penetrated by the points of the larger acanthostyles. Microscleres, sigmas only, are visible in the dermal membrane, becoming scarce in the interior. Overall spicular density is low.

Spicules. Large acanthostyles, small acanthostyles, tornotes, sigmas; no chelae.

Large acanthostyles, relatively thin, rather sparsely spined, with heads barely developed and irregularly shaped, 155– 193.6 –215 × 3.5– 5.4 –8 µm.

Small acanthostyles, rather similar to the larger ones, not clearly separated morphologically, 85– 93.9 –112 × 3– 3.8 –5 µm.

Tornotes thin, straight, inequiended, one end sharply pointed, the other mucronate or swollen elongately, often irregular, 143– 162.6 –191 × 0.5– 1.05 –1.5 µm.

Sigmas thin, with ends somewhat incurved, with irregular surfaces, in a large size range, possibly in 2 almost overlapping size categories, overall 14– 19.3 –30 µm, larger 22–30 μm, smaller 14–20 µm.

Etymology. The species is named from the word “ Anatolia ”, since the species lives along the western coasts of Anatolia.

Habitat. The sponge is very rare on subhorizontal surfaces of mixed sand and rock, up to 30 m depth.

Geographic distribution. Western coasts of Turkey. Thus far, known only from the type locality, İbrice Harbor (Edirne), Saros Bay, northern Aegean Sea .

Remarks. Hymedesmia spp. possessing sigmas but lacking chelae are quite rare. In the Northeast Atlantic- Mediterranean area, there is only a single species described with this combination of spicules, Hymedesmia (Hymedesmia) tenuisigma Lundbeck, 1910 , from the deepsea habitat in the waters around Iceland. This species clearly differs from our material by having much larger sigmas (84–120 µm) and much longer acanthostyles of the larger category (300–830 µm). There is little similarity between the 2 species other than their possession of sigmas as the only microsclere type. Some superficial similarity is also apparent with Hymesigmia japycina Topsent, 1927 , a deep-water species from the Azores, which combines a hymedesmioid skeleton with the absence of chelae and the presence of sigmas. However, the sigmas of the latter species are quite peculiar, forming almost a closed ring and being polytylote. Van Soest (2000) assigned H. japycina to the genus Hymenancora Lundbeck, 1910 on account of shared sigma morphology with chela-bearing Hymenancora inaequalis ( Topsent, 1927) . The sigmas (70–85 µm) and acanthostyles (660 µm) of H. japycina are clearly larger than those of our species.

Order Halichondrida Gray, 1867

Family Halichondriidae Gray, 1867

Genus Axinyssa Lendenfeld, 1897 ( Figure 3 )

Axinyssa digitata ( Cabioch, 1968)

Syn. Pseudaxinyssa digitata Cabioch, 1968

Material examined. RMNH Por. 7479, Turkey, Bebek 4.

Description

Growth form. Massive, uniformly covered with thin fistulesapproximately 1 cmlongprojectingperpendicularly from base; 2 specimens about 3 × 4.5 × 6 cm and 6 × 7 × 6 cm (in Figure 3 , A 1 , A 2 , C).

Color. Light yellow.

Surface. Hispid.

Ectosome. Not specialized; thin and clear collagen membrane pierced by choanosomal spicules.

Choanosome. Plumose-halichondroid; confused and disorganized at base and becoming plumose near surface; bounded by clear spongin with some areas clear of spicules. Axial skeleton not differentiated. Spongin fibers not developed. Spicule tracts multispicular, plumose, poorly developed at choanosome base; anastomosing and diverging towards surface where they become more defined; projecting slightly through ectosome.

Spicules. Oxeas curved, fusiform or hastate; often with one end bent or bifurcated; thinner forms common. Less common styles in the same size category; axial filament visible; 589.6–976.6 µm (736.8 ± 84.3) × 4.7–17.3 µm (13.8 ± 2.7)

Habitat. The sponges are common on subhorizontal surfaces of mixed sand and rock, up to 40 m depth.

Geographic distribution. This species was originally described by Cabioch (1968) from the Atlantic coast of France (Roscoff), and was subsequently reported to occur in the Gulf of Cadiz near the Straits of Gibraltar by Carballo et al. (1996). Unconfirmed records of the species were provided by Mustapha et al. (2003) from Tunisia and by Voultsiadou (2005a, 2005b) from the Lebanese coasts. This first record from the coast of Turkey and the Aegean Sea confirms its presence in the eastern Mediterranean.

Three further species we recorded are new to the sponge fauna of Turkey.

Axinyssa aurantiaca (Schmidt, 1864) . One specimen from station İbrice (Edirne) at a depth of 36 m on 30.08.2012 .

Figures

Figure 1. Map of Turkish seas and site locations of new species and new records of sponges.

Figure 2. Hymedesmia (Hymedesmia) anatoliensis sp. nov., SEM images of the spicules of the holotype RMNH Por. 7456: A. Large acanthostyle; A1. Detail of head; B. Small acanthostyle; C. Tornote; C1. Details of apices of tornote; D. Large and small sigmas.

Figure 3. Axinyssa digitata (Cabioch, 1968): A1–A2, habit of specimen RMNH Por. 7479; B. Drawing of various oxeote and stylote spicules, scale bar = 100 µm; C. Cross-section of surface projection showing lax arrangement of spicules, scale bar = 500 µm.