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| Format: | Recurso digital |
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Zenodo
2025
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| Online adgang: | https://doi.org/10.5281/zenodo.20317366 |
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Indholdsfortegnelse:
- <p><b>HIPPASTERINAE Verrill 1899</b></p><p>Verrill, 1899: 174; Fisher, 1906: 1165; 1910: 223; Spencer & Wright, 1966: U58; Mah <i>et al</i>., 2010: 270; Mah <i>et al</i>. 2014: 425.</p><p><b>Diagnosis</b></p><p>Based on Mah (2024). Pulpy tissue present, covering plates. Abactinal plates with spiny-granular or angular accessory fringe. Abactinal plates tightly abutted. Superomarginal and inferomarginal plates, variably round to quadrate with large, prominent spines or tubercles in most taxa. Pedicellariae enlarged, abundant, and on raised base. Disk thick and strongly arched in most.</p><p><b>Comments</b></p><p>Although only 4 genera are included within the Hippasterinae, there appears to be a rich species diversity within <i>Evoplosoma</i> and <i>Hippasteria</i> as further species have been described as deep-sea settings have been further explored. <i>Hippasteria</i> is known from 12 species distributed throughout the Pacific, Atlantic, and Indian oceans from wide-ranging depths. <i>Evoplosoma</i> is known 14 species, primarily collected from deep-sea settings (1000–4000 m). Revisions to <i>Hippasteria</i> in conjunction with further specimens have resulted in the discovery of the wide-ranging <i>Hippasteria phrygiana</i> as well as several previously undescribed species (Foltz <i>et al</i>. 2013; Mah <i>et al</i>. 2014; Mah, 2020). <i>Evoplosoma</i>, a deep-sea octocoral predator has similarly been found to include numerous species, including some with wide distributions, such as <i>Evoplosoma voratus</i> (Mah, 2020; 2024).</p><p>Hippasterines are known primarily as predators on cnidarians,especially colonial octocorals but also including sea anemones and antipatharians (Mah <i>et al</i>., 2010, Mah 2020, 2024)). The morphology in hippasterines has been argued as associated with this predatory behavior (Mah 2024) but how spines and pedicellariae function in this regard is poorly understood. Pedicellariae various types are present in all 4 genera, with <i>Gilbertaster, Sthenaster</i> and <i>Hippasteria,</i> with all having prominent and numerous bivalve pedicellariae on abactinal, marginal and actinal surfaces versus <i>Evoplosoma</i> with tong-like or paddle-shaped pedicellariae.</p><p>Pedicellariae large, bivalve similar to those on abactinal surface on marginal plate surface, many bisecting the width of the plate. Spines absent from superomarginal and inferomarginal plate series. Granules, densely arranged, covering superomarginal and inferomarginal plate series. Superomarginal and inferomarginal plates quadrate at interradius. Fasciolar grooves on marginal and actinal surfaces absent. Fringe of accessories on marginal plates poorly differentiated. Superomarginal plates forming prominent dorsolateral fringe. Actinal plates covered by 1–15 flattened, polygonal, angular granules. Large bivalve pedicellariae similar to those on abactinal and marginal plate surfaces, abundant on actinal plates. Actinal plates with granules but lacking large spines or spinelets. Pedicellariae, bivalved, present on plate series at perpendicular angle, adjacent to ambulacral furrow. Pedicellariae, flat-tong shaped, with serrated blades present on actinal plates. Pedicellariae on raised bases, abundant. Furrow spines two to four (usually three) blunt, thickened spines, horizontally flattened (<i>G. anacanthus</i>) to triangular/quadrate in cross-section (<i>G. caribaea</i>). Subambulacral spines, 1–4, blunt, flattened. Round to quadrate (<i>G. anacanthus</i>) to triangular in cross-section (<i>G. caribaea</i>). Pedicellariae, bivalved, enlarged on first adambulacral (similar to others) replacing subambulacral spination and sometimes replacing furrow spination. Subambulacral spines smaller in size, more abundant. Furrow spines round in cross-section.</p><p><b>Comments</b></p><p><i>Gilbertaster</i> includestwospecies, <i>Gilbertasteranacanthus</i> Fisher 1906 and <i>Gilbertaster caribaea</i> (Verrill, 1899), in the tropical Pacific and tropical Atlantic respectively. <i>Gilbertaster</i> is unusual for the sheer abundance of large, bivalve pedicellariae present on the abactinal, marginal, and actinal surfaces (Figs 20A–D), perhaps more so than any other valvatacean asteroid.</p>