Phorticium multispinum Popofsky, 1912

Zhang, Lanlan & Suzuki, Noritoshi, 2017, Taxonomy and species diversity of Holocene pylonioid radiolarians from surface sediments of the northeastern Indian Ocean, Palaeontologia Electronica (Cambridge, England: 2003) 7 (8), pp. 1-68 : 42-43

Phorticium multispinum Popofsky, 1912 sensu emend.

Figure 24.1-3

1912 Phorticium multispinum Popofsky , p. 153- 154, text-fig. 76.

1980 Octopyle octopyle Haeckel ; Boltovskoy and Riedel, pl. 4, fig. 9.

Description. Test is elliptical to rounded-rectangular in shape (length ratio of the longest axis to the middle axis: ca. 1.3) and consists of a central combination, a rounded rectangular 1st pseudo-concentric shell, a 2nd pseudo-concentric shell with two gates, four long spines that are orthogonally arranged relative to each other on the Sq-plane, three to six pillar beams visible from the aperture of the 2nd pseudo-concentric shell, and numerous radial spines distributed throughout the 2nd pseudo-concentric shell. The 1st and 2nd pseudo-concentric shells are arranged in the same orientation. The 1st pseudo-concentric shell appears to be completely latticed. The 2nd pseudo-concentric shell consists of a subrounded twin girdle along the Lt-axis, and is directly connected with the 1st pseudo-concentric shell on both sagittal sides of the center. Pillar beams are present between the 1st and 2nd pseudo-concentric shells. Less than eight pillar beams are present between the 1st and 2nd pseudo-concentric shells in the direction of the Lt-axis. Most of these pillar beams pierce through the 2nd pseudo-concentric shell to form fine cylindrical radial spines. Two lateral spines, one apical spine and one basal spine, extend from the central combination fully mature. Pores of the 2nd pseudo-concentric shell are subcircular to elliptical in shape. Four or five pores are aligned along the Lt-axis on the joint between the 1st and 2nd pseudo-concentric shells. Eight to 10 pores are aligned along the Pl-axis on the 2nd pseudo-concentric shell. The size ratio of the 2nd pseudo-concentric shell to the 1st pseudo-concentric shell is 2.2 along the Lt-axis and 2.3 along the Pl-axis.

Remarks. Phorticium multispinum Popofsky, 1912 , is similar to Phorticium rotundospinosum ( Tan, 1993) , but the former differs from the latter in the former’s absence of many pillar beams between the 1st and 2nd pseudo-concentric shells and of radially distributed radial spines around the 2nd pseudo-concentric shell. The juvenile form of Phorticium multispinum without longer lateral spines is similar to Phorticium scitulum n. sp., but the former is distinguishable from the latter based on the former’s greater numbers of pillar beams between the 1st and 2nd pseudo-concentric shells and former’s larger size.

Figures

FIGURE 24. Photographs of the encountered morphotypes of Phorticium multispinum Popofsky, 1912 sensu emend. (1-3) and Phorticium itakii n. sp. (4-6). All are Pl-view at Type 1, Fr-view at Type 2. Scale bar equala 0.1 mm. All specimens are from YDY05-01.