Megapogon villosus

• Main Authors: Alvizu, Adriana, Xavier, Joana R., Rapp, Hans Tore
• Format: Other/Unknown Material
• Language: unknown
• Published: 2019
• Subjects: Biodiversity; Taxonomy; Animalia; Porifera; Calcarea; Leucosolenida; Achramorphidae; Megapogon; Megapogon villosus; Antarctic; Burton; Winter Quarters Bay; Antarc*
• Online Access: https://zenodo.org/record/5584074; https://doi.org/10.5281/zenodo.5584074

Megapogon villosus (Jenkin, 1908) (Figs 14 A–F, 15A–D; Table 11) Original description. Jenkin 1908, p. 37, pl. XXXVI, figs 115–119. Type locality. Winter Quarters Bay, Antarctic. Synonym and citations. Megapogon villosus, Burton 1929, p. 403; M. villosus, Burton 1963, p. 93, 527 (figs 333–334). Material examined. Lectotype: BMNH-1907.8.6.146 (fragments of one specimen and four slides), National Antarctic Expedition (HMS Discovery). Paralectotype: BMNH-1907.8.6.151 (one fragmented specimen and one slide), National Antarctic Expedition (HMS Discovery). Paralectotype: BMNH-1907.8.6.153 (one fragmented specimen and one slide), Winter Quarters Bay, National Antarctic Expedition (HMS Discovery). Paralectotype: BMNH-1907.8.6.152: one slide, National Antarctic Expedition (HMS Discovery). Morphology. Vase-shaped sponge, without a well-developed oscular fringe. Surface strongly hispid due to a dense mat of very long diactines, which point down towards the base of the sponge (Fig 14A). The lectotype is 14.6 mm long, 3.6–7.8 mm wide, and 0.8–1.1 mm thick. Colour beige in ethanol. Aquiferous system seems to be leuconoid with rounded choanocyte chambers scattered in the mesohyl (Figs 14 B–C). Skeleton. Cortical skeleton composed of tangentially arranged triactines, and a dense mat of long diactines that cross the surface (Fig 14D). Smaller and spiny microdiactines are placed around the inhalant pores (Fig 14E). In the choanoskeleton there are chiactines and triactines with their unpaired actines that can project through the surface (Figs 14 C–F). The atrial skeleton comprises chiactines with their long unpaired actines pointing towards, and often projecting through the cortex (Figs 14 C–F). The atrial wall is supported by the paired actines of the chiactines, and among them some triactines and microdiactines can be found (Fig 15A). Spicules. Diactines: very long and straight with sharp points. Most of them were broken (Fig 15B, Table 11). Microdiactines: small and slightly bent diactines. Some smooth, and some with spines. ...