Sphaerolarnacillium tanzhiyuani, Zhang & Suzuki, 2017

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 : 50-51

Sphaerolarnacillium tanzhiyuani n. sp.

Figure 29

zoobank.org/ 2C1CA41A-F0DD-4133-8401-D00E0BBDC498

1976 Lithelius ? sp. Tan and Tchang, p. 264, text-fig. 35.

1984b Tholospira sp. Nishimura and Yamauchi, pl. 16, fig. 13.

1985 Streblacantha circumtexta JØrgensen? Boltovskoy and Jankilevich, pl. 3, fig. 20.

1992 Phorticium spp. Sugiyama, Nobuhara, and Inoue, pl. 1, figs. 2-3, 5 (only).

cf. 1995 Phorticium octopyle (Haeckel) ; van de Paverd, p. 197-198, pl. 57, figs. 6-8 (only).

1995 Phorticium indet. van de Paverd, pl. 58, fig. 2.

1995 Pylonidae gen. et sp. indet. van de Paverd, pl. 58, figs. 3, 6, 8?, 10.

1995 Pylonids gen. et sp. indet. van de Paverd, pl. 59, figs. 3-5.

cf. 2009 Hexapyle sp. Matsuoka, fig. 3.19.

Etymology. In honor of Prof. Tan Zhiyuan, a Chinese radiolarian specialist.

Holotype. Specimen in Figure 29.4-6 from the sample YDY05-01.

Paratype. Specimen in Figure 29.11-13 from the sample YDY05-01.

Description. Test is spherical to oblong-spherical in shape and consists of a larnacillid central combination, one complete pseudo-concentric shell, and several long, thin radial spines. Well-regulated girdles are coiled along one of the Lt-, Sg-, or Pl-axes. The complete larnacillid central combination appears flattened and quadrangular with rounded corners. The 1st pseudo-concentric shell also appears spherical to oblong-spherical in shape, with a more circular outline than the larnacillid central combination. Gates are present on both Sgsides of the 1st pseudo-concentric shell, and these gates are closed with a normal pore frame in fully mature specimens. The 1st pseudo-concentric shell is connected to the larnacillid central combi-

PALAEO- ELECTRONICA.ORG nation by several pillar beams, and almost all of these pillar beams pierce through the 1st pseudo-concentric shell to become cylindrical radial spines. Radial spines are the same length as half of the diameter of the 1st pseudo-concentric shell.

Remarks. Sphaerolarnacillium tanzhiyuani n. sp. is easily distinguished from all other Sphaerolarnacillium species because of its smaller size and more rounded shape. In contrast to the Sphaerolarnacillium cochleatum , Sphaerolarnacillium tanzhiyuani has more thorns.

Dimensions. Based on the holotype specimen. The length and width of the outer concentric shell: 110.2 μm and 99.0 μm; The ratio of length to width of the outer concentric shell: ca. 1.1. The length of radial spines: ca. 12.5–35.7 μm.

Figures

FIGURE 29. Photographs of the encountered morphotypes of Sphaerolarnacillium tanzhiyuani n. sp. All are Fr-view at Type 2. Scale bar equals 0.1 mm. All specimens are from YDY05-01.