Rotasphaera Noble, 1994

Noble, Paula, Aitchison, Jonathan C., Danelian, Taniel, Dumitrica, Paulian, Maletz, Jörg, Suzuki, Noritoshi, Cuvelier, Jessie, Caridroit, Martial & O’Dogherty, Luis, 2017, Taxonomy of Paleozoic radiolarian genera, Geodiversitas 39 (3), pp. 419-502 : 437

Rotasphaera Noble, 1994

Rotasphaera Noble, 1994: 19 .

TYPE SPECIES. — Rotasphaera marathonensis Noble, 1994 ( Noble 1994: 21, pl. 2, fig. 1-4, pl. 8, fig. 1-2).

AGE AND LOCATION OF TYPE MATERIAL. — Silurian, Caballos Novaculite, Texas, USA.

TAXON CODE. — 074.

STATUS. — Junior synonym of Secuicollacta Nazarov & Ormiston, 1984 (by Dumitrica et al. 2000).

DIAGNOSIS. — “Shell may be round to polygonal in outline with six to nine primary spines which are morphologically distinct from the secondary spines. Primary spines are commonly blunt-ended or tapered, may exhibit blades or grooves at the proximal end, and are circular in cross section at the distal end. Secondary spines are commonly thin non-tapered rods or nodes which range from 5 to 50% of the primary spine length.” ( Noble 1994: 19).

REMARKS

Noble (1994) distinguished Rotasphaera from Secuicollacta Nazarov & Ormiston 1984 by the fewer number of primary spine units and greater differentiation between primary and secondary spines. There has been some discussion in the literature as to whether Rotasphaera should be considered a junior synonym to Secuicollacta ( Jones & Noble, 2006) . MacDonald (1998; 2003) maintained that the two genera should be separate, and that Rotasphaera lacked an ectopic spicule. Herein, we include Rotasphaera in Secuicollacta despite differences between primary and secondary spine morphology. The absence of an ectopic spicule in the secuicollactines recovered from Caballos material ( Noble 1994) is likely a function of preservation.