Clathrina brandtae, Rapp, Hans Tore, Göcke, Christian, Tendal, Ole Secher & Janussen, Dorte, 2013

Rapp, Hans Tore, Göcke, Christian, Tendal, Ole Secher & Janussen, Dorte, 2013, Two new species of calcareous sponges (Porifera: Calcarea) from the deep Antarctic Eckström Shelf and a revised list of species found in Antarctic waters, Zootaxa 3692 (1), pp. 149-159 : 152-154

Clathrina brandtae sp. nov.

( Figure 2 , Table 2)

Synonyms and citations: Clathrina primordialis (Jenkin 1908 pars: 6; Brøndsted 1931 pars: 4-9; Koltun 1976: 163; Barthel et al. 1997: 46–47); Clathrina sp. nov. 14 (Klautau et al. 2013).

Type locality: Eckström Shelf, Eastern Weddell Sea, Antarctica . SYSTCO station 71/48-1 at 70° 23.94' S, 8° 19.14' W, 602.1 m depth to 70° 23.89' S, 8° 18.67' W, 595.2 m depth.

Type material: Holotype SMF 11867, paratype SMF 11866 (fragmented specimen), both from the type locality.

Additional material examined: EASIZ Expedition. Weddell Sea (1 incomplete specimen), st ps 39/24, 21.02.1996, 71°S8.15’W, 118–123 m depth (Barthel et al. 1997).

Etymology: Named after Professor Angelika Brandt for her great efforts organizing the ANDEEP and SYSTCO expeditions.

Description: Clathrinidae composed of a clathroid body of very irregularly and loosely anastomosing tubes. The cormus is narrower at the base than in the oscular region. The holotype is 1.5 cm high and 1 cm wide. There is one apical osculum. The paratype and additional material examined are fragmentary and the true shape of the cormus is not clear. Colour in life is yellowish beige and almost white in alcohol. No granular cells could be observed. Consistency is soft.

The skeleton is composed of regular triactines and regular to subregular tetractines. Tetractines is the most abundant spicule type ( Figure 2 B). Spicules are intermingled without any organization ( Figure 2 C). However, the spicules of the single tubes are overlapping and therefore form a thicker layer than is found in the most simply built species of Clathrina . The apical actines of the tetractines are pointing into the interior of the asconoid tubes. Triactines are most common in the outermost layer of the tube wall. Otherwise there is no special orientation of the spicules.

Spicules: Triactines: They are regular with slender and sharply pointed and conical actines (102-153-200 µm x 7 µm) ( Table 2, Figure 2 ).

Spicule Length (Μ m) Width (Μ m)

min max mean mean s n

Holotype, SMF 11867

Triactines 102 200 153 ±25.8 7.7 ±0.5 30

Tetractines 100 235 153 ±23.9 6.5 ±1.0 30

Apical actine 50 138 82 ±21.5 5.0 ±0.7 30

Paratype, SMF 11866

Triactines 123 200 159 ±21.6 8.3 ±1.7 30

Tetractines 135 225 164 ±20.2 7.3 ±0.7 30

Apical actine 50 113 87 ±5.1 5.1 ±0.9 30 Tetractines: The tetractines are similar to triactines. Some are slightly subregular. Apical actine is long, smooth, slightly curved and sharp (100-153-235 µm x 6.5 µm, apical actine 50-87-113 µm x 5.1 µm) ( Table 2, Figure 2 ).

Molecular identification: ITS1-5.8S-ITS2 sequences of the paratype has been deposited in GenBank under the accession number KC874655 .

BLAST search confirmed the poriferan origin of the sequence, with Clathrina contorta (Minchin, 1905) as the closest match.

Distribution: Antarctic. Weddell Sea (this article and Barthel et al. 1997), Kemp Land (Koltun 1976), Kaiser Wilhelm II-Land (Brøndsted 1931) and the Winter Quarters (Jenkin 1908).

Remarks: The name Clathrina primordialis (Haeckel, 1872) has erroneously been used for different species of Clathrina from most oceans, representing the majority of Clathrina species with a skeleton consisting of spicules with sharply pointed actines (e.g. Arnesen 1900; Brøndsted 1931; Burton 1963). However, it is now well established that C. primordialis is a Mediterranean species with a skeleton solely composed of triactines (Klautau & Valentine 2003), and recent examination of material from a wide geographical range, previously identified as C. primordialis , have resulted in description of a number of new species of Clathrina (e.g. Klautau & Borojevic 2001; Rapp et al. 2001; Rapp 2006).

So far only one additional species of Clathrina is known from the Antarctic, namely Clathrina broendstedi Rapp et al., 2011 ( Table 1). C. brandtae sp. nov. and C. broendstedi are very different as tetractines is the dominant spicule type in the former and the latter has only triactines. The loose and irregular anastomosis of tubes, large size of spicules, in combination with tetractines being the most abundant spicule type is rare within the genus. Based on organization of the cormus, organization of spicules as well as spicule size, C. biscayae Borojevic & Boury- Esnault, 1987 appears to be the closest. However, in C. biscayae the spicules are mainly parasagittal while in C. brandtae sp. nov. they are regular. Recently it has been shown that the genus Clathrina is not monophyletic (Rossi et al. 2011; Voigt et al. 2012). Based on molecular and morphological evidence Rossi et al. (2011) suggested that the genus should comprise only species with a skeleton composed of triactines, and species with additional di- and tetractines should be transferred to other genera and/or new genera should be erected. However, as none of the new clades were defined and given names, we choose to place C. brandtae sp. nov. provisionally in the genus Clathrina , awaiting formal description of the different groups within the old “ Clathrina ”. In a molecular phylogeny based on the D2 region of 28S as well as the entire region comprising the two spacers (ITS1 and ITS2) and the 5.8S ribosomal DNA, C. brandtae clusters within a well-defined group also containing C. biscayae and with Clathrina contorta as the most closely related species (Klautau et al. 2013).

Figures

FIGURE 2. Clathrina brandtae sp. nov. A. Preserved Holotype from the Weddell Sea (SMF 11866) (os = osculum). B. Spicules of C. brandtae sp. nov. From left: ste = subregular tetractine, rte = regular tetractine, rtri = regular triactine and aa = apical actine of a tetractine. C. Wall of asconoid tube seen from the interior.