Larcopyle variabile ( Dreyer, 1889 )

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 : 30

Larcopyle variabile ( Dreyer, 1889) sensu emend.

Figure 18.1-6

1889 Ommatodiscus (Ommatodisculus) variabilis Dreyer , p. 109-110, fig. 58.

? 1995 Spongurus ellipticus (Ehreberg) ; van de Paverd, p. 151, pl. 53, fig. 13 (only).

? 1995 Tholospironium cervicorne Haeckel ; van de Paverd, p. 185-186, pl. 54, fig. 12 (only).

Description. Test has a spindle-like to ellipsoid shape without a tube around the bore pylome, and consists of a pylodiscid-type central combination, two spherical pseudo-concentric shells, and an outermost coverage shell. The Lt-axis of the central combination is oblique to the longest axis of the overall test. The 1st pseudo-concentric shell is connected with the 2nd pseudo-concentric shell by numerous straight pillar beams. The 2nd pseudo-concentric shell ranges from spherical to ellipsoid in shape and is connected with the outermost coverage shell by straighter pillar beams. The pillar beams between the 1st and 2nd pseudo-concentric shells are generally disconnected from those between the 2nd pseudo-concentric shell and the outermost coverage shell. The outermost coverage shell has a rough surface with circular to subcircular pores of variable sizes. The wall of the outermost coverage shell tends to be in direct contact with part of the 2nd pseudo-concentric shell at the mid-portion of the test. The ratio of the short and long diameters of the outermost shell is ca. 0.6. Both the apex and pylomate-ends of the test tend to have a space between the 2nd pseudo-concentric shell and the outermost coverage shell.

Remarks. The type illustration shown in figure 58 of Dreyer (1889) does not show the central combination. Our specimen can be classified as this species based on its relatively large, spherical 1st pseudo-concentric shell, spherical 2nd pseudo-concentric shell, and its very little to no space between the 2nd pseudo-concentric shell and the outermost coverage shell at the mid-portion of the test. Larcopyle variabile ( Dreyer, 1889) is distinguishable from Larcopyle nebulum Lazarus, Faust and Popova-Goll, 2005 , based on the former’s rougher surface of the outermost coverage shell, former’s more concentric or spiraled internal structures, and the spongy structure inside the space in the apex and pylomate ends of the test between the outermost coverage shell and the final pseudo-concentric shell of the former.

Figures

FIGURE 18. Photographs of the encountered morphotypes of Larcopyle. 1-6, Larcopyle variabile (Dreyer, 1889) sensu emend.; 7-12, Larcopyle molle n. sp.; 13-18, Larcopyle eccentricanoides n. sp.; 19-22, Larcopyle pulchella n. sp. All are Fr-view at Type 2. Scale bar equals 0.1 mm. All specimens are from YDY05-01.