Zygolithus bijugatus Deflandre in Deflandre & Fert, 1954 validated by Deflandre, 1959; permissible in ICZN, code use by Deflandre.
Sujkowskiella Hay et al., 1966
Pseudozygrhablithus Haq, 1971
In the plan view, Zygrhablithus exhibits symmetrical extinction lines at an angle of 45 °, characteristic of a rhombohedral crystal structure. In species with symmetrical extinction, the elongation direction cannot be determined.
Elliptical holococcoliths with a distal process exhibit significant variation in the shape and size of the distal process. The base consists of approximately 15–20 crystal layers, composed of minute crystals often smaller than 0.2 μm. The coccolith precisely constructs Zygrhablithus using four crystalline blocks, similar to those shown in Fig. 16.1 by Varol 2025b, of the distal process. The base consists of approximately 15–20 crystal layers, composed of minute crystals often smaller than 0.2 μm. The coccolith precisely constructs Zygrhablithus using four crystalline blocks, similar to those shown in Fig. 16.1 by Varol 2025b, shaping their bases into a predefined elliptical structure
Deflandre, G. & Fert, C. 1954. Observations on current and fossil coccolithophorids in ordinary and electron microscopy. Annales de Paléontologie 40: 115-176.
Deflandre, G. 1959. Sur les nannofossiles calcaires et leur systématique. Revue de Micropaléontologie 2: 127-152.
Haq, B. U. 1971. Paleogene calcareous nannoflora. Parts I-IV. Stockholm Contributions in Geology 25: 1-158.
Hay, W. W., Mohler, H. P. & Wade, M. E. 1966. Calcareous nannofossils from Nal'chik (northwest Caucasus). Eclogae Geologicae Helvetiae 59: 379-399.
Varol, O. 2025b. New observation on Paleocene holococcoliths. Neues Jahrbuch für Geologie und Paläontologie,