Brianellium Cheng, 1986

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 : 462

Brianellium Cheng, 1986

Brianellium Cheng, 1986: 180 .

TYPE SPECIES. — Brianellium holdsworthi Cheng, 1986 ( Cheng 1986: 182, pl. 3, fig. 13, 14, 17, 23).

AGE AND LOCATION OF TYPE MATERIAL. — Lower Carboniferous, Oklahoma and Arkansas, USA.

TAXON CODE. — 182.

STATUS. — Valid.

DIAGNOSIS. — “Test composed of four rays extending from a central sphere forming a tetrahedral or pyramid-like structure. Inter-radial angles between any two rays equal to or close to 120°. Central sphere differentiated into a cortical shell and a medullary shell. Wall structure of cortical shell is labyrinthine in pattern consisting of intricately interlacing, relative thin bars, which form an irregular, loose, spongy meshwork. Centrally placed medullary shell, usually relatively small in size, spherical to subspherical in shape, consisting of a latticed wall with polygonal pore frames. Four primary beams connected between medullary shell and cortical shell, originating from the wall surface of the medullary shell, equally positioned and extending through the central sphere, continuous with tip of four rays forming four spines. Rays cylindrical with loosely spongy wall structure, circular in axial section.” ( Cheng 1986: 180).

REMARKS

The gross external structure of this form shows variation from sub pyramidal to quadrilobate, and in some ways is similar to Quadrilobus, and less to Tetratormentum . Based on these observations we do not follow De Wever et al. (2001) in treating this genus as a junior synonym to Tetratormentum , and leave the species as valid until additional analysis can be performed on material of this age. The description of a spherical to subspherical medullary shell and 4 rays fits within the definition of the family Latentifistulidae sensu De Wever et al. (2001) , although placement in the Pseudolithellidae may also be appropriate.