Achramorpha glacialis Jenkin 1908
Achramorpha glacialis Jenkin, 1908 (Figs 5 A–H; Table 5) Original description. Jenkin 1908, p. 31, pl. XXIV, figs 98–102. Type locality. Winter Quarters Bay, Antarctic. Synonyms and citations. Achramorpha glacialis, Dendy & Row 1913, p. 765; A. glacialis Hôzawa 1918, p. 542; A. glacialis, Brønst...
| Main Authors: | , , |
|---|---|
| Format: | Other/Unknown Material |
| Language: | unknown |
| Published: |
2019
|
| Subjects: | |
| Online Access: | https://zenodo.org/record/5584064 https://doi.org/10.5281/zenodo.5584064 |
| Summary: | Achramorpha glacialis Jenkin, 1908 (Figs 5 A–H; Table 5) Original description. Jenkin 1908, p. 31, pl. XXIV, figs 98–102. Type locality. Winter Quarters Bay, Antarctic. Synonyms and citations. Achramorpha glacialis, Dendy & Row 1913, p. 765; A. glacialis Hôzawa 1918, p. 542; A. glacialis, Brønsted 1931, p. 31; A. glacialis, Burton 1963, p. 93, 524, fig 330. Material examined. Lectotype: BMNH-1907.8.6.101 (one complete specimen and one slide), National Antarctic Expedition (HMS Discovery), collection date 05.09.1902. Paralectotype: BMNH-1907.8.6.103-104 (three fragments of a specimen and three slides), National Antarctic Expedition (HMS Discovery), collection date 23.01.1903. Morphology. Cylindrical sponge, slender at the base and towards the apical osculum. Surface slightly hispid due to cortical diactines that cross the surface. Colour is white-beige in ethanol (Fig 5A). Aquiferous system syconoid with long choanocyte chambers that taper at their distal ends, forming large inhalant cavities (Fig 5B). The lectotype is 5.6 mm long, 0.4–0.7 mm wide and 0.2–0.3 mm thick. Skeleton. Cortical skeleton made up by triactines arranged tangentially, and by protruding diactines and trichoxeas (Figs 5 B–C). Neither the diactines nor trichoxeas are arranged in tufts or bundles, but rather irregularly scattered. Minute and spined microdiactines are found also in the cortical skeleton (Fig 5D). The atrial skeleton is composed of chiactines which are placed radially with the unpaired actine pointed towards the choanosome, the paired actines adjacent to the atrial wall, and the apical actine projected towards the atrial cavity (Fig 5B). Tetractines are found only in the oscular region with the unpaired actines pointing downwards, the paired actines tangentially lined up with the atrial wall, and the apical actines pointing towards the atrium (Fig 5E). The oscular fringe is not well-developed and is composed mainly of short trichoxeas, and some scattered diactines (Fig 5C). Spicules. Cortical diactines: bent, with sharp tip ... |
|---|