Clathrina sueziana, Klautau & Valentine, 2003

Klautau, Michelle & Valentine, Clare, 2003, Revision of the genus Clathrina (Porifera, Calcarea), Zoological Journal of the Linnean Society 139 (1), pp. 1-62 : 43-45

CLATHRINA SUEZIANA SP. NOV.

Original name: Clathrina canariensis var. compacta Row, 1909

Etymology: From the type locality.

Type locality: Suez, Red Sea .

Type: BMNH 1912.2 .1.3 (holotype /alcohol). Suez, Red Sea. C. Crossland Collection .

Citation: Burton (1963).

BMNH 1912.2 .1.3 is the holotype of C. canariensis var. compacta .

Colour: The cormus of the holotype of C. canariensis var. compacta , now C. sueziana sp. nov., is white when preserved.

Description: Cormus of the holotype formed of thin, irregular and loosely anastomosed tubes. A large tube functioning as an osculum is physically connected to thinner water-connecting tubes, receiving the excurrent water from them.

The skeleton has no special organization, comprising equiangular and equiradiate triactines and tetractines ( Fig. 35A ) in roughly the same proportions. They are similar in size. Their actines are cylindrical or conical, with a blunt tip. Some of them are larger in the middle. The apical actine of the tetractines has almost the same diameter at the base as the facial actines. It is conical, shorter, straight, smooth and sharp. Trichoxeas are also present but there are very few.

Remarks: Row (1909) said that this specimen was identical to C. compacta as described by Schuffner from the Mauritius Islands, and that he could not separate it from C. canariensis ( Miklucho-Maclay, 1868) either. Furthermore, he said that Thacker (1908) had described many intermediate forms of C. canariensis from the Cape Verde Islands. Consequently, if C. canariensis was so plastic morphologically, var. compacta could be one of its forms rather than a distinct biological species.

Row (1909) therefore decided to designate this specimen from the Red Sea as a variety of C. canariensis , because it differed greatly from the C. canariensis described by Haeckel (1872) (Miklucho-Maclay’s description was not complete). However, one important problem is that Row did not describe C. canariensis var. compacta . Fortunately, we were able to analyse the type specimen of this variety and compare it with that of C. canariensis . Although we did not have the holotype of C. compacta , we were able to compare this species with var. compacta through the literature; var. compacta differs from C. canariensis and C. compacta in its spicules and the organization of the cormus.

When we examined Schuffner’s drawing of the cormus of C. compacta , we observed that this species has no water-collecting tubes, while C. canariensis and var. compacta do. The spicules of C. compacta (120/ 12 Mm according to Schuffner) are larger than those of var. compacta . Moreover, Schuffner only described conical actines, while var. compacta also has cylindrical ones. Nor did he mention the presence of spicules with actines wider at the middle, as we found in var. compacta .

In relation to C. canariensis, var. compacta has a similar cormus organization, with water-collecting tubes, but its spicules vary enormously. In C. canariensis , only cylindrical actines are present, all with blunt tips. The size of the spicules only differs slightly, C. canariensis having shorter spicules:

Length (Mm) Width (Mm)

Triactines 67.5 77.8 ± 4.6 87.5 5.0 0 30 Tetractines 62.5 74.3 ± 5.8 87.5 5.0 0 30 Apical actine 35.0 43.8 ± 5.6 55.0 5.0 0 15

Length (Mm) Width (Mm)

Triactines 72.0 81.6 ± 6.2 96.0 5.5 ± 0.7 20 Remarks: C. hispanica sp. nov. is a common species in the Mediterranean Sea. At first sight its spicules can be mistaken for those of C. clathrus . However, C. clathrus has actines which are slightly thicker and their tips are strongly rounded, and not blunt as in C. hispanica . Moreover, the colour of the cormus of C. hispanica is white and not the characteristic yellow of C. clathrus .

We did not include C. rubra Sarà, 1953 in our list of species, as we had only received a slide of spicules that were not well preserved. We took some measurements of these spicules so that we could compare them with those from C. hispanica . Despite some similarity in relation to the cylindrical shape of the actines, their thickness is different, being thinner in C. hispanica ( C. rubra triactines: 71 Mm (±9)/9 Mm (±1)). C. hispanica could also be considered similar to C. canariensis , although the latter differs in having tetractines.

Figures

Figure 35. Clathrina sueziana sp. nov. Triactine and tetractine. Scale bar = 100 Mm.