From Fensome et al., 2019:
Hystrichosphaeridium senii Srivastava and Banerjee, 1969, p.104, pl.1, fig.12. Holotype: Srivastava and Banerjee, 1969, pl.1, fig.12. Questionable assignment: Stover and Evitt (1978, p.56) as a problematic species. Age: Eocene.

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Original description: [Srivastava and Banerjee, 1969]:

Hystrichosphaeridium senii sp. nov.
Plate 1, Fig. 12

Diagnosis : Body spindle shaped, light brown. Body wall distinct, 1 thick, finely granulate. Processes simple, stif, solid and uniformly thickened. Tips closed, slightly curved to one side.

Measuremenis : Body size 58.3 x 30.6 μ. Processes: 8-13.3 μ long.

Comparison: No species known to the authors is directly comparable to the Indian specimens. The character of the processes justifies a distinction at specific level, hence new species namnely H. senii has been proposed.

Remarks: Two specimens were found. An interesting feature observed in the specimens is the presence of a(?) furrow, represented by a thin area extending from one to another end along the long axis. Its exact nature - whether morphological or due to any physical deformity - is difficult to ascertain with the data at hand. However, it does not appear to have been caused due to physical deformity. The species has been named after Dr. J. Sen.
Holotype: Sl.no. C4/19-25 cms (ii); 34-7: 92-3
Type locality Assam, N. E. India; TDW5, 3800 - 3803 m.