Notioceramus abyssalis Mah 2023, n. sp.
Notioceramus abyssalis n. sp. FIGURE 10A–F Notioceramus anomalus Mah 2011: 32 (part). Etymology The species epithet abyssalis is from the Latin for the abyss alluding to this species occurrence at great depth. Diagnosis Stellate species (R/r=2.0–2.6) interradial arcs weakly curved to straight. Arms...
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| Format: | Other/Unknown Material |
| Language: | unknown |
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Zenodo
2023
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| Online Access: | https://doi.org/10.5281/zenodo.8090158 http://treatment.plazi.org/id/03C387E86610FFC7FF68E19F841BFBC6 |
| Summary: | Notioceramus abyssalis n. sp. FIGURE 10A–F Notioceramus anomalus Mah 2011: 32 (part). Etymology The species epithet abyssalis is from the Latin for the abyss alluding to this species occurrence at great depth. Diagnosis Stellate species (R/r=2.0–2.6) interradial arcs weakly curved to straight. Arms tapering, elongate. Abactinal granules (3 counted along a 1.0 mm line at R=4.0) surface finely spinose (appearing “fuzzy”), forming continuous cover with plate boundaries remaining visible (versus those species with granular cover obscuring plate boundaries) (Fig. 10A, B, C). Marginal plates, 34–44, covered by spinose granules, 10–30, identical to those on abactinal surface. Actinal intermediate surface covered by cylindrical spines with blunt spinose tips. Furrow spines 3, subambulacral spines 2, one short and one large (Fig 10D, F). Comments Notioceramus abyssalis n. sp. is one of two Notioceramus species collected from a substantially deeper depth (2782–3876 m versus 73–1120 m) than Notioceramus anomalus as outlined by Fisher (1940) and A.M. Clark (1962). Depth occurrence is comparable to if not potentially deeper than that of Notioceramus neillae n. sp. As compared with Notioceramus anomalus , granules of Notioceramus abyssalis are much and are much more densely packed (three granules along a 1.0 mm line at R=4.0 cm) compared with the N. anomalus as outlined by Fisher (1940) which shows only a single coarse granule present on a 1.0 mm line (at R=4.0 cm). Furrow spine number in this species is greater (n=3) versus two in N. anomalus . Notioceramus neillae n. sp. also displays pointed spines on its actinal plate surface whereas spines of N. anomalus are thick, blunt granules. Occurrence Off South Georgia Island, South Orkney Islands, Scotia Sea, South of Burdwood Bank, Elephant Island. 2782– 3876 m. Description Body stellate (R/r=2.0–2.63), arms tapering, weakly elongate, termini upturned. Interradial arcs weakly curved to straight. Disk strongly arched (Fig 10A, B, C). Abactinal surface composed of plates, abutted, ... |
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