Demospongiae of ANT XXIV / 2 (SYSTCO I) Expedition — Antarctic Eastern Weddell Sea Author Göcke, Christian Author Janussen, Dorte text Zootaxa 2013 3692 1 28 101 journal article 10.11646/zootaxa.3692.1.5 ddffc7b3-2654-49ec-b046-f32bc78af2d6 1175-5326 249019 136660B8-7DCC-490E-AB79-46546CC18E40 Haliclona (Gellius) tylotoxa (Hentschel, 1914) ( Fig. 22 , Tab. 18 ) Haliclona tylotoxus (Hentschel, 1914) : Koltun 1964: 102, 1976: 195. Synonymy: Gellius tylotoxus Hentschel, 1914: 131 , pl. 4, fig. 14, pl. 8, fig. 13. Material. 1 specimen from station 048-1 (SMF 11778), 602.1 m , 70° 23.94' S , 8° 19.14' W , 12.01.2008 . Description. Specimen ( Fig. 22 A) massive, rounded, about 4 cm in diameter, probably growing on bryozoans, some of these incorporated into tissue. One osculum at the top, opening into a deep inner cavity, penetrating the sponge almost to its base, with a more or less constant width. Surface porous with regularly arranged pores, covered by an epidermis spiked by long diactins, giving it a hexactinellid-like appearance. These diactins of hexactinellid origin and foreign to the sponge. Sponge quite firm, slightly compressible. Color in ethanol lightly beige. Skeleton: Skeleton irregular, poorly organized ( Fig. 22 B–C). Only in parts, oxeas form rudimentary anisodictyal or anisotropic reticulations. Spicule density high. Microscleres usually occuring independently of megascleres in tissue-rich regions. Around pores, skeleton might become somewhat alveolate. Detachable epidermis irregular, containing oxeas and microscleres. Spiculation ( Tab. 18 ): Main spicules very slightly bent oxeas ( Fig. 22 D), 610–770 x 12.5–25 µm. Characteristic microscleres tylotoxas ( Fig. 22 G–H), 175–258 µm in length and 6.25–10 µm in maximal width (tyle diameter). Tyle centrally arranged, toxas usually angularly bent in the middle. Tylotoxas not very abundant, but occuring regularly and most characteristic for the species. Most abundant microscleres sigmas ( Fig. 22 E–F). These with wide size range, 50–290 µm by 25–120 µm. At first glance two different size classes of sigmas present, spicule measurements show occurrence of all intermediate sizes. Remarks. The holotype described by Hentschel (1914) was cylindrical, upright tube-shaped and therefore somewhat different from our new, more compactly rounded specimen. The new specimen might therefore be a juvenile one, which just started by growing sidewards and would eventually have been growing vertically. Differences in growth forms may also be induced by other parameters, such as current or different types of substrates available. The holotype as well as the new specimen show no attachment structure, but have incorporated several bryozoans; both sponges probably grew on bryozoans. Spicule sizes presented by Hentschel (1914) and Koltun (1964) are similar to those of our new specimen; the great variability in size of sigmas is present in earlier records as well. Still, our new specimen shows larger maximum values than sponges reported before. This is in accordance with our observation of the occurrence of unusually large spicules in some other species from station 048-1, e. g. H. (G.) flagellifera . FIGURE 22. Haliclona (Gellius) tylotoxa (Hentschel, 1914) , SMF 11778. A, habit in ethanol. B–C, skeletal sections. D, oxea, E–F, sigmas, G–H, tylotoxas (LM). Scale bars: A: 20 mm, B: 1 mm, C: 2 mm, D: 100 µm, E–H: 30 µm. TABLE 18. Spicule sizes of Haliclona (Gellius) tylotoxa (Hentschel, 1914) . Values in µm are given as follows: minimum–mean–maximum (number of spicules measured). For comparison, values from Hentschel (1914) and Koltun (1964) are given. parameter SMF 11778 Hentschel (1914) Koltun (1964) Oxea length 610–703.9–770 (33) 632–732 632–760 diameter 12.5–22–25 (33) 20–25 Sigma length 50–146–290 (35) 16–200 16–200 max. width 25–61.9–120 (35) Tylotoxa length 175–220.9–257.5 (30) 136–224 136–224 diameter/ tyle 6.25–7.5–10 (30)