Clathrina canariensis (Miklucho-Maclay, 1868)

Klautau, Michelle & Valentine, Clare, 2003, Revision of the genus Clathrina (Porifera, Calcarea), Zoological Journal of the Linnean Society 139 (1), pp. 1-62 : 12-14

CLATHRINA CANARIENSIS (MIKLUCHO- MACLAY, 1868)

Original name: Nardoa canariensis Miklucho- Maclay, 1868

Type locality: Lanzarote Beach, Canary Islands.

Type: PMJ-Inv. Nr. Porif. 103 (syntype /alcohol). Lanzarote Beach, Canary Islands, Haeckel u. Miklucho- Maclay .

Citations: Haeckel (1872); Lackschewitsch (1886); Thacker (1908); Dendy & Row (1913); Hôzawa (1918, 1933, 1940); Breitfuss (1932); Tanita (1941, 1942, 1943).

A syntype of C. canariensis , which is deposited in PMJ under the registration number Porif.103 Calcarea was examined. Our description for this species is closer to Haeckel’s than Miklucho-Maclay’s. There are three fragments, all well preserved in alcohol, the largest measuring approximately 2.2 ¥ 1.5 ¥ 0.8 cm.

Colour: Varies from white to light yellow.

Description: Cormus formed of thin, irregular and tightly anastomosed tubes, which are variable in diameter. Large water-collecting tubes converge, forming oscula that are projected above the surface.

The skeleton of the tubes is thin (its wall has 4-5 layers of spicules), and it comprises an irregular meshwork containing triactines and tetractines ( Fig. 8A ). The apical actine of the tetractines is always found inside the tubes. The length of the apical actine is never longer than the diameter of the tubes.

Regular triactines are the most abundant spicules. The size of the triactines and tetractines is very uniform. Actines are almost cylindrical and straight, with a blunt tip. The distal part of the actines is frequently slightly undulated. The apical actine of the tetractines ( Fig. 8B ) is straight, smooth and sharp at the tip, and it has the same diameter as the facial actines. Frequently, it is shorter, but its length is variable. The shape of the triactines resembles that of C. clathrus .

Remarks: Clathrina canariensis was described by Miklucho-Maclay (1868) under the name Nardoa canariensis . As in other clathrinas, some confusion is associated with C. canariensis , and several species have been subsumed to become its synonyms. The following species, at some point in time, have been considered synonyms of C. canariensis :

Nardoa rubra Miklucho-Maclay, 1868

Nardoa sulphurea Miklucho-Maclay, 1868

Ascaltis compacta Schuffner, 1877

Leucosolenia nanseni Breitfuss, 1896

Leucosolenia tenuipilosa Dendy, 1905

Clathrina canariensis var. compacta Row, 1909

Nardoa rubra and N. sulphurea were described by Miklucho-Maclay (1868) in the same article in which he described N. canariensis and he gave them the status of distinct species. He said that the distinction between them was based only on their different colours ( N. canariensis was white, N. rubra was red and N. sulphurea , yellow). He gave no further information.

Haeckel (1872) again described C. canariensis as Ascaltis canariensis ; his description, more complete than that of Miklucho-Maclay, became the accepted one. He analysed specimens collected by both of them in the Canary Islands (Lanzarote Beach). He questioned the validity of N. rubra and N. sulphurea as true species, saying that the colour of other ascones was very changeable, and that the three forms did not show any differences in relation to their spicules. He also criticized the description made by Miklucho- Maclay, which had not mentioned the presence of tetractines and papillae in the inner surface of the tubes of C. canariensis . Indeed, Miklucho-Maclay said only that ‘Spicula sind dreistrahlig’ (‘Spicules are triactines’), and he did not mention the tetractines. Therefore, Haeckel described C. canariensis as a species with changeable colours, and equiangular and equiradiate triactines and tetractines with similar dimensions. The apical actine of the tetractines was described as straight, sharp, smooth and as thick as the facial actines. This became the accepted description of C. canariensis .

Thacker (1908) considered A. compacta Schuffner, 1877 , L. nanseni Breitfuss, 1896 and L. tenuipilosa Dendy, 1905 to be synonyms of C. canariensis , as well as agreeing with Haeckel’s opinion on, N. rubra and N. sulphurea . He considered L. nanseni to be a synonym because he did not feel that the size of the spicules, the shape of the apical actine, and the presence of papillae were satisfactory for the purpose of identification, as he had already found intermediary forms of sponges that possessed them. Thacker also commented that he thought L. nanseni resembled A. compacta , which has regular triactines and tetractines and was found off Mauritius. Schuffner, however, had separated A. compacta from C. canariensis ‘because (1) it had no papillae on the inner surfaces of ‘the Ascon-tubes’ and ‘because’ (2) of the different shape of the apical rays of the quadriradiates’. Nonetheless, Thacker said that he had found great variability in the apical actines of his specimens. As he considered the use of papillae a poor character to distinguish species due to its variability, he decided to include A. compacta in C. canariensis , and said that C. canariensis also did not differ from L. nanseni .

Thacker deemed L. tenuipilosa to be only a variety of C. canariensis , with ‘the same relationship to typical specimens of L. canariensis as L. coriacea ceylonensis ’. He said that he had found hair-like oxea (trichoxea) in several of the specimens from the Cape Verde Islands, and that in some specimens, these spicules were numerous, but in others, very scarce, and that the latter specimens ‘form connecting links between the typical form of the species and the variety L. canariensis tenuipilosa .’ However, the subsequent year, Row (1909) rejected the synonym of L. tenuipilosa with C. canariensis , saying that ‘the presence of oxea of such unusual and constant form, being very long and extremely slender, should undoubtedly separate it specifically from forms where oxea are entirely absent, even though the number and frequency of the oxea may show very considerable variation as they do in Thacker’s specimens.’

In this same article, however, Row described a specimen that he said was identical to A. compacta , but that he could not separate from C. canariensis , because ‘all intermediate forms have been described by Thacker from the Cape Verde Islands’. However, as the specimen he was analysing was so different from the typical C. canariensis described by Haeckel (he did not mention Miklucho-Maclay’s description), he decided to consider it as a distinct variety: C. canariensis compacta from the shore at Suez.

With respect to the previously considered synonyms or varieties, there was only the opportunity to analyse the type specimen of C. canariensis var. compacta , but it could be compared with A. compacta and L. nanseni , from the original descriptions in the literature. In relation to N. rubra and N. sulphurea , no comments can be made, as there were no specimens available to analyse, and their description in the literature is very incomplete.

Although from the description the external shape of C. canariensis and C. canariensis var. compacta could seem similar, they are not. As in many other clathrinas, both have an aquiferous system consisting of large water-collecting tubes, which terminate in a larger tube projected above the surface, functioning as an osculum. However, the cormus of C. canariensis is tight, while that of C. canariensis var. compacta is loose, which apparently is not due to the state of its preservation.

Nevertheless, the most important differences between them are in the skeleton: the presence of trichoxeas in C. canariensis var. compacta , the shape and the size of the actines, and the proportion of the triactines and tetractines. The trichoxeas could be enough to separate them as distinct species. However, the differences in the shape, size and proportion of triactines and tetractines seem to be more important. The spicules of C. canariensis are shorter and have cylindrical actines, while those of C. canariensis var. compacta are larger and very conical. Moreover, C. canariensis has almost the same number of triactines and tetractines, while C. canariensis var. compacta has more triactines than tetractines.

The holotype of C. compacta was not found. However, comparing the description given by Schuffner with the holotype of C. canariensis , it is possible to distinguish between these species due to the differences in the size of the actines. The spicules of C. compacta are much longer and thicker than those of C. canariensis (120 Mm/12 Mm).

The syntype of C. canariensis was shown to be very different from other specimens deposited in BMNH under that name. This observation suggests that the distribution of this species is much narrower than previously imagined (Arctic; Atlantic coasts of Europe; Mediterranean; Cape Verde and the Canary Islands; Mexico; Mauritius; Red Sea; NW Pacific (Commandorski Islands); Japan) sensu Burton (1963). Observations during this study suggest that the distribution of C. canariensis is possibly restricted to the Atlantic coasts of Europe and, perhaps, the Mediterranean Sea.

We therefore suggest that the specimen PMJ- Inv.Nr.Porif. 103 be treated as a lectotype of C. canariensis .

Figures

Figure 8. Clathrina canariensis. A, triactines and tetractines. B, apical actines of the tetractines projected into a tube. Scale bar = 100 Mm.