Corollithion exiguum Stradner, 1961
A loxolith with regular to elongated hexagonal walls encloses a central area that contains a structure with four to six arms, each commonly supporting a distal process.
The protolith outer wall remains in constant extinction, while the protolith inner wall often exhibits weak interference colours in the plan view under XPL. The inner wall and the distal process display length-slow (+) elongation in the side view.
The extinction angles of the inner wall are approximately 55° in Corollithion kennedyi and Corollithion karegae. The apparent angle between the extinction on the tube cycle is 73°, corresponding to an obliquity angle of 17° in Corollithion completum, Corollithion exiguum, Corollithion signum, and Corollithion msakyae.
Corollithion and Stoverius share a similar construction characterised by a double protolith wall, but differ in overall morphology: hexagonal in Corollithion and circular to elliptical in Stoverius.
Stradner, H. 1961. Vorkommen von Nannofossilien im Mesozoikum und Alttertiär. Erdoel-Zeitschrift 77(3): 77-88.