It is monotypic, being represented by the single species Sphenostethus taslei.

[2] Craighead noted that its larvae are unusual in their habit of boring into dry dead treetop limbs, rather than damp wood near the ground[2] This point was contested by Vlasak & Vlasakova, who recorded that S. taslei larvae were more frequently found in fallen limbs, not necessarily preferring treetop branches.

They also argued against the association with dry branches, finding instead a larval preference for limbs of smaller diameter compared to other prionids.

[3] Various hardwoods are used as larval hosts, including oak, chestnut, and redbud.

[4] Craighead remarked that the adults of this species are rarely seen, but the larvae are quite common.