Didimospyrgos inciae Varol, 2025b
Derived from the Greek “didimos pyrgos”, meaning twin tower, referring to its twin distal process.
Didimospyrgos is a small, elliptical to hexagonal holococcolith with a ring-shaped wall that is two crystalline units high (double-storey) and one crystalline unit wide, with each storey consisting of about twelve crystalline units. The central area is filled with multiple single-layer crystalline units that support a two-part distal process.
In plan view, the wall of Didimospyrgos displays first-order greyish-white interference colours. Inclined extinction lines of the wall on the distal side form an angle of approximately 63 °, indicating a rhombohedral crystal structure, and exhibit length-fast (–) elongation. The central structure remains in constant extinction in the plan view and shows first-order white interference colours with length-slow (+) elongation in the side view.
Didimospyrgos can be distinguished from Aplofoteino by its two crystalline high walls and a central structure with a distal process, whereas Aplofoteino has a single crystalline high wall and a vacant central area. Didimospyrgos is also differentiated from Munarinus and Varolia by its two crystalline high walls and inclined extinction lines, indicative of a rhombohedral crystal structure. In contrast, Munarinus and Varolia exhibit a single-crystalline-high wall with parallel extinction lines, characteristic of a hexagonal prism structure. Additionally, Munarinus features a disjunct block exhibiting interference colours in the central area in the plan view. In contrast, the central structure of Didimospyrgos remains in constant extinction under the same orientation. Didimospyrgos, Diorofostoichos, and Perideraiolithos all possess two crystalline high ring-shaped walls. Didimospyrgos is set apart by its multi-crystalline central structure, which is in constant extinction in the plan view, supporting a two-part distal process. In contrast, Diorofostoichos and Perideraiolithos have central structures that exhibit interference colours under the same orientation. Furthermore, Didimospyrgos is distinguished by its inclined extinction lines, whereas Diorofostoichos displays symmetrical extinction lines
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