Clathrina coriacea, (MONTAGU, 1818)

Klautau, Michelle & Valentine, Clare, 2003, Revision of the genus Clathrina (Porifera, Calcarea), Zoological Journal of the Linnean Society 139 (1), pp. 1-62 : 22-23

CLATHRINA CORIACEA ( MONTAGU, 1818)

Original name: Spongia coriacea Montagu, 1818

Type locality: Budleigh Salterton, S. Devon, England .

Type: BMNH 1882.3 .6.7 (suggested neotype /dry). Budleigh Salterton, S. Devon, England. H.J. Carter Collection .

Citations: Gray (1821, 1867); Fleming (1828); Johnston (1842); Bowerbank (1866, 1874, 1882); Haeckel (1872); Carter (1877); Vosmaer (1881); Ridley (1881); Fristedt (1885, 1887); Vosmaer (1887); Hanitsch (1890, 1895); Topsent (1891, 1892, 1894, 1936); Grentzenberg (1891); Knipowitsch (1893); Minchin (1896); Breitfuss (1898, 1927, 1932, 1935, 1936); Arnesen (1901); Jenkin (1908); Lundbeck (1909); Row (1909); Dendy & Row (1913); Ferrer-Hernandez (1918); Prenant (1925); Burton (1926, 1929, 1933, 1963); Arndt (1928, 1935, 1941); Row & Hôzawa (1931); Burton & Srinivasa Rao (1932); Renouf (1936,1937); Tanita (1942, 1943); Borojevic & Grua (1964); Borojevic (1967); Johnson (1978).

The type locality of C. coriacea is Budleigh Salterton, S. Devon, England. However, Montagu elected no holotype. The lack of a holotype and the poor original description caused C. coriacea to be considered morphologically variable and widespread. We are electing a dried specimen collected by Carter in Budleigh Salterton ( BMNH 1882.3.6.7), as the neotype of C. coriacea .

Colour: Dried specimen is light brown.

Description: Cormus formed of thin, irregular and loosely anastomosed tubes. Water-collecting tubes are present ( Fig. 15A ). The skeleton has no special organization, comprising equiangular and equiradiate triactines ( Fig. 15B ). Actines are conical or slightly conical, undulated at the distal part and with a constriction near the tip, which is rounded or blunt. The spicules resemble those of C. clathrus and C. aurea . However, in these species, actines are cylindrical.

Remarks: Montagu first described C. coriacea in 1818 under the name Spongia coriacea . This description, however, is very incomplete, as it only discusses the external form of this sponge. Johnston (1842) gave a better description and provided an illustration of the spicules. The specimens he studied, however, were from Scarborough (Berwick Bay) and Dublin Bay, and not from the type locality. In his Monograph of the British Spongiadae, Bowerbank (1866) again described C. coriacea . In this work, he widened the distribution to other places in Britain, although, curiously, he did not mention the type locality. Interestingly, although Bowerbank uses the name coriacea , he commented that ‘Montagu’s description of his Spongia coriacea applies very much more correctly to a small specimen of Raphyrus griffithsii (a siliceous sponge) of this work than to the calcareous species described above’.

In his monograph, Haeckel (1872) distinguished C. coriacea , C. clathrus and C. primordialis on the basis of differences in the shape of the actines of the triactines and geographical distribution. According to Haeckel, C. clathrus could be distinguished from the others by the characteristic shape of its spicules (triactines with undulated actines and a rounded tip) and its restricted distribution in the Adriatic Sea. C. coriacea , on the other hand, he considered to be more widespread, found ‘on the Atlantic coasts and islands of Europe ( Norway, Britain, Ireland, France) and appear[ing] to take the place of A. primordialis ’. He used the actines to distinguish the species: cylindrical in C. primordialis and conical in C. coriacea . He also studied specimens from the type locality (Lesina, Adriatic Sea) and then described a species with undulated actines and rounded tips as Ascetta clathrus .

Carter (1884) studied specimens from Budleigh Salterton, South Devon, to try to clarify the problem. He either overlooked or ignored the morphological differences pointed out by Haeckel. He considered C. clathrus to be a synonym of C. coriacea , and concluded that the confusion surrounding the latter ‘has arisen from Haeckel having made a separate species of Schmidt’s Grantia clathrus under the name of Ascetta clathrus , with a different form of spicule from that which Schmidt has given as characteristic of it.’ The problem is that Schmidt (1864) did not made a good drawing of C. clathrus and did not describe the shape of the actines of his G. clathrus . As already mentioned, we have had the opportunity to examine Schmidt’s specimen and the description made by Haeckel matches it perfectly. Consequently, Carter seems to have created the confusion, by considering C. coriacea and C. clathrus synonymous.

Minchin (1900) described what he considered to be morphotypes of C. coriacea , and stated that this species was very plastic, although characteristic of the North Atlantic. Despite this, C. coriacea continued being described as being found from localities worldwide.

Topsent (1936) analysed several specimens from the Mediterranean Sea (identifying them as C. coriacea ), and said that he had found great morphological variability in this species. He placed several species in synonymy with C. coriacea , including C. primordialis , and concluded that C. coriacea was a cosmopolitan species. After that time, several authors began to identify as C. coriacea clathrinas whose skeletons only comprised triactines.

As initially proposed by Haeckel (1872), Borojevic & Peixinho (1976) and Borojevic & Boury-Esnault (1987) distinguished C. coriacea (English Channel) and C. primordialis (tropical Atlantic, although probably erroneously) on the basis of actine shape.

We therefore conclude that C. coriacea is a distinct species with characteristic morphological features that can be easily used to recognize it. Furthermore, it does not seem to be cosmopolitan, but a geographically well-defined species from the North Atlantic.

Figures

Figure 15. Clathrina coriacea. A, photograph of the neotype (¥ 10). B, triactines. Scale bar = 100 Mm.