Glabraster A.H. Clark 1916
Glabraster A.H. Clark 1916 Figure 5 A–F Glabraster A.H. Clark 1916: 122 Type species: Porania magellanica Studer 1876 (a synoym of Porania antarctica Smith 1876) Diagnosis. Body weakly pentagonal to strongly stellate (R/r= 1.51–2.85). Arms, triangular in shape, varying from well-developed and elonga...
| Main Authors: | , |
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| Format: | Other/Unknown Material |
| Language: | unknown |
| Published: |
2014
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| Online Access: | https://zenodo.org/record/6133835 https://doi.org/10.5281/zenodo.6133835 |
| Summary: | Glabraster A.H. Clark 1916 Figure 5 A–F Glabraster A.H. Clark 1916: 122 Type species: Porania magellanica Studer 1876 (a synoym of Porania antarctica Smith 1876) Diagnosis. Body weakly pentagonal to strongly stellate (R/r= 1.51–2.85). Arms, triangular in shape, varying from well-developed and elongate, contiguous with body to short and emerging abruptly from well-developed disk. Body generally tumescent. Prominent skin overlying abactinal, marginal and actinal surfaces. Plate outlines obscured in wet specimens. Abactinal plates forming widely-spaced, reticulate pattern. Skin present between widely reticulate plates bearing small ossicles among many of the open spaces. Spines present or absent on abactinal plates. When present, spines are prominent and present individually on each plate. Spines, short with thorn-like or blunt tips tend to be most prominent on plates where confluences of bands are present but they are also present in several individuals on individual abactinal bands. Marginal plates imbricate, differing in size. Superomarginals 3 x– 4 x larger than inferomarginals. Superomarginal plates, polylobate in shape, plate boundaries obscured by thickened tissue in wet specimens. Superomarginals with no spines, but spinelets variably present. Inferomarginal plates, irregularly polygonal, rounded and pinch out two to four plates before terminus in larger specimens but form nearly complete series in smaller individuals (R> 1.5 cm). Inferomarginals form actinolateral fringe, with one or two flattened spatulate spines present on each plate. Actinal plates, imbricate, forming transverse series between adambulacrals, plates skin covered, otherwise surficial accessories absent in most (i.e., no granules, no spinelets, etc.). Furrow spine (s) pointed, narrow, sheathed in skin, variably one or two, set within the furrow. Subambulacral spines, one or two, paddle shaped, larger than furrow spines (approximately twice as thick) with blunt tips. Subambulacral tips vary from more widely flattened to strongly cuved ... |
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