Catalog entries: Dictyospyris melissium
Original description: Shell discoidal, very variable in size and irregularity of outline, complexly subdivided by internal structures. Externally the shell is formed of a lattice plate with numerous small, circular to subeircular pores. Near the center of one surface of the disc is a larger pore. toward which is directed an internal thorn. Interior of shell traversed by numer-ous, delicate and robust, transverse and oblique (sometimes anastomosing) rods, except for a small central area evident in some specimens as a two or three-lobed cavity. This cavity and the internal thorn directed toward the larger pore indicate that this form is an acanthodesmiid, but the complexity of the internal structures prevents our being able to determine which bars are parts of the sagittal ring or collar structures.
Remarks on original description: Because it has not been possible to determine the nature of the sagittal ring, nor the phylogenetic development of this species, its assignment to Dictyospyris is very tentative. There is some resemblance to Psychospyris, in the honeycomb-like internal structure of the peripheral part of the disc, but D. melissium has a much smaller internal cavity than the members of that genus, and its stratigraphic range is clearly prior to the origin of the Psychospyris lineage.[comment from RadWorld database]
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:
Dictyospyris melissium compiled by the radiolaria@mikrotax project team viewed: 20-4-2021
Short stable page link: https://mikrotax.org/radiolaria/index.php?id=203940 Go to Archive.is to create a permanent copy of this page - citation notes