Stylodictya validispina


Classification: rads_cenozoic -> Spongodiscidae -> Stylodictyidae -> Stylodictya -> Stylodictya validispina
Sister taxa: S. aculeata, S. gracilis, S. hastata, S. inaequalispina, S. multispina, S. ocellata, S. orbiculata, S. rosella, S. stellata, S. tainemplekta, S. targaeformis, S. tenuispina, S. validispina, S. sp.

Taxonomy

Citation: Stylodictya validispina Jørgensen 1905
Rank: species

Catalog entries: Stylodictya validispina

Original description: The structure is, on the whole, the same as in the foregoing species [Stylosphaera tenuispina]. The strange, peculiar, strongly convex central part is, however, wanting (the disc is homogeneous) and the margin is furnished with numerous strong spines which are almost regularly distributed.
Shape of the shell in side view: Broadly linear (the disc is of almost even thickness) but little narrower at the margin than in the middle, with sharp or obtuse corners, not clearly rounded off at the ends, but almost square. There are short spines scattered on the central part.
The system of rings: From the innermost little shell 4 radial rods extend in the shape of a cross to the first ring, as in the preceding species. The ring itself is also here an irregular quadrangle with rounded corners. Outside this ring, there are three others, connected to each other by radial rods whose number increases outwards. In the prolongation of the 4 primary radial rods (from the inmost shell) may be seen, more or less clearly, some similar ones which are rather crookedly placed, and these conjoin to form 4, more or less definite, zigzag rods, which go through the whole system of rings. On the outside ring there are numerous (21) equatorial, narrowly conical, marginal spines.
Pores: The pores in the centre are very small, punctiform, very scattered with wide intermediate spaces, gradually larger outwards, on the two outer rings about 2 on the space between the rings, uneven in size up to 4µm or a little larger. Between the pores on the central part very small, punctiform byspines are scattered which may easily be overlooked.
Radial spines: Numerous, narrowly conical (subulate), strong radial spines of different lengths, the longest being little more than 1/2 of the radius of the disc. Some project out from the ring next to the outside one, several too from the one next to the inmost one, and yet a few from the innermost one.
Byspines: A few scattered ones, very short and very small, needle shaped, extend from the central part of the disc.

Dimensions: The diameter of the inner shell 14µm, of the first ring:34µm, of the second 60µm, of the third 84µm, of the fourth 102µm. In thickness 24µm.
The specimen illustrated appears to be almost fully developed. Probably only the small portion of the outer ring which is not seen in the illustration, is all that is wanting. Distinguishing characters (rw): This species exhibits a certain amount of agreement with S. stellata Bailey (1856, pl.11, fig.20), which has, however, fewer and broader spines, and also differs in other respects.
Remarks on original description: [Synonymized with Stylodictya stellata Bailey by Petrushevskaya, 1975c, p.576]

Description

Biogeography and Palaeobiology

Biostratigraphic distribution

Geological Range:
Last occurrence (top): within (-Ma, top in "Holocene" stage). Data source:
First occurrence (base): within (-Ma, base in stage). Data source:

Plot of occurrence data:

References:


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Stylodictya validispina compiled by the radiolaria@mikrotax project team viewed: 25-10-2020

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