Suberites lutkenii Morozov, Strelkova, Zimina & Sabirov, 2023, s. lat.

Suberites lutkenii s. lat. Schmidt 1870

Suberites lütkenii: Schmidt 1870, p. 47, Pl. V, fig. 7; Marenzeller 1886, pp. 11–12; Topsent 1913, pp. 25–26; Hentschel 1929, p. 872; Burton 1934, p. 14; Alander 1942, p.79; Laubenfels 1953, pp. 12–13, fig.7.

Suberites montalbidus: Carter 1880, p. 256; Carter 1882, p. 353; Fristedt 1885, pp. 19–20, Pl. 2, figs. 4a–e; Fristedt 1887, pp. 428–429; Levinsen 1893, pp. 413–414, fig. 23; Lambe 1894, pp. 127–128, pl. III, fig. 6a–c; Lambe 1900, pp. 24–25; Swartschewsky 1906, p. 318 –319, pl. XIII, fig. 3; Morozov et al. 2019, pp. 2973–2975, fig. 8a–h;

Suberites spec.: Vosmaer 1882, pp. 32–33; pl. I, figs 22–23; pl. IV, figs 140–144.

Suberites domuncula ficus: Koltun 1959, p. 95, figs 66–67; pl. XXXIV, figs 1–3; pl. XXXVI, figs 1–2.

Suberites lutkenii Schmidt 1870 is another example of a taxonomically problematic species. Schmidt described a fig-shaped S. lutkenii from the North Sea and East Greenland. According to Schmidt (1870), the choanosomal skeleton of this sponge consisted of loose spicule tracts and single spicules (styles), running along the main body axis; centrotylote microrhabds (both microstrongyles and microxeas) found in the superficial layer. It’s worth mentioning an unusual variety of microsclere allocated by Schmidt (1870, pl. 5, fig. 7b). Most likely this variety can be attributed to the developmental forms of microscleres.

Subsequently Carter (1880) allocated a new species obtained from the Barents Sea, which he named Suberites montalbidus, providing a few lines about its general appearance. In the following paper Carter (1882, p. 353) asked himself whether his Suberites montalbidus is synonymous to S. lutkenii described earlier by Schmidt (1870).

Later Vosmaer (1882) published a description of sponge dredged in the same area as Carter’s specimens— the Barents Sea. Vosmaer (1882, pp. 32–33) doubted whether to assign his Suberites spec. to S. virgultosus (= Halichondria virgultosa Johnston 1842) or S. montalbidus Carter, 1880. He pointed out at the resemblance between his sponge and S. virgultosus (= Hymeniacidon virgultosa (Bowerbank 1866, 1874)). However, the appearance of little spines on the microscleres of Vosmaer’s sponge brought him to another species, S. montalbidus Carter 1880. As opposed to the previous authors, Vosmaer (1882) was first to thoroughly analyze the spicule complement of his Suberites spec. (1882). He described and illustrated the following kinds of spicules:

1) principal spicules—subtylostyles straight, rather short-pointed, with barely visible basal swelling;

2) the former spicules make a transition to tylostyles and subtylostyles, with a fully pronounced basal swelling;

3) centrotylote microrhabds, both microxea and microstrongyles, which are especially to be found on the surface of the sponge.

Fristedt (1885; 1887), referring to the aforementioned works of Carter (1880) and Vosmaer (1882), reported Suberites montalbidus from almost across the Arctic and adjacent parts of the North Atlantic and Pacific oceans. Fristedt (1885) synonymized S. montalbidus with S. lutkenii Schmidt 1870.

Marenzeller (1886) supposed Suberites montalbidus Carter 1880 to be a junior synonym of S. lütkenii Schmidt, 1870. Many subsequent studies supported this point of view (Topsent 1913; Hentschel 1929; Burton 1934; Alander 1942; de Laubenfels 1953).

In light of more recent work, it is now apparent that in the Arctic/Subarctic Suberites lütkenii s. lat. constitutes a species complex. Two distinct morphotypes were recently differentiated into the two valid arctic species by Morozov et al. (2019): S. montalbidus and S. cebriones. The former should be treated as a junior synonym of S. lutkenii, since these two sponges are indistinguishable, at least as far as spicule complement, skeleton architecture and overall form and habitat are concerned. On the other hand, S. cebriones is a valid eastern-Arctic species (see below).