- Type images:
type image: S. balbis
type image: S. balbis
Catalog entries: Spongatractus balbis
type image: S. balbis
type image: S. balbisOriginal description: Cortical shell ellipsoidal, thick-walled, with subcircular pores (approximately 8-13 on the half-equator), joined to the double medullary shell by bars lying approximately in the equatorial plane, and usually two bars collinear with the polar spines. On the surface of the cortical shell are one to three layers of meshwork formed by connection of the distal ends of small superficial thorns. Two-bladed polar spines are somewhat variable in form and size, but are commonly robust, about half as long as the cortical shell, with a change in contour from parallel-sided proximally to tapered distally.
Remarks on original description: The thick-walled ellipsoidal cortical shell is covered by one to three layers of spongy meshwork, formed by connection of the distal ends of superficial thorns. The cortical shell has approximately 8-13 subcircular pores on the half-equator. Two bladed polar spines are variable in form and size, commonly robust, about half as long as the cortical shell, with a change in contour from parallel-sided proximally to tapered distally. (Sanfilippo et al., 1985)[comment from RadWorld database]
Geological Range:
Last occurrence (top): within Paleogene Period (23.03-66.04Ma, top in Chattian stage). Data source: Lazarus et al. 2015 - "P age group"
First occurrence (base): within Paleogene Period (23.03-66.04Ma, base in Danian stage). Data source: Lazarus et al. 2015 - "P age group"
Plot of occurrence data:
References:
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Spongatractus balbis compiled by the radiolaria@mikrotax project team viewed: 31-3-2023
Short stables page link: https://mikrotax.org/radiolaria/index.php?id=205465 Go to Archive.is to create a permanent copy of this page - citation notes |