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Dendrospyris (?) sakaii Sugiyama and Furutani, 1992

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Cephalis clearly two-lobate externally, without an apical spine; bars thinner than those of the preceding species, forming small, circular to oval cephalic pores and relatively large sagittal-lattice pores (Goll, 1958), bearing many, simple nodes on themselves. Secondary meshes are often present, but they are independent of the nodes and developed between pores. Two I are completely fused with the basal ring when one views from the base. Ax moderately developed. Thorax roughly latticed; the proximal part generally consisting of six or more longitudinal bars, one of which is a prolongation of D, and pierced by subcircular pores of large size, and the middle to distal part formed of thinner bars, terminated in needle-like or distally forked teeth. Thoracic pores change into angular shape of smaller size. Secondary meshes possibly developed on the proximal part of thorax.
This species resembles D. (?) suganoi from which it is distinguished externally by the feature of cephalic secondary meshes and lacking an apical spine and internally by the amalgamation of two I and the basal ring and the development of Ax. It is also provisionally assigned to Dendrospyris in this study as well as the preceding species, but they should be separated at generic level in future judging from their skeletal differences. D. (?) sakaii also represents one of characteristic acanthodesmiids from the Oidawara Formation.
Height of- test 115-185 µm; maximum width of test 95-143 µm; based on 22 specimens.
This species is named after Prof. Toyosaburo Sakai of Utsunomiya University in honor of his contribution on Cenozoic radiolarian study.
Sugiyama and Furutani 1992











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