Original description of Drepanocheilus (Tulochilus) erebus by Stilwell, 2000:
- "Shell quite small for family (height about 15-20 mm), thin, delicate, alate; spire angle approximately 15º; growth lines weak, opisthocline; spire high with more than 6 angulate, subquadrate whorls; protoconch incomplete, but apparently polygyrate with small nuclear whorls; last whorl biangulate, with moderately strong subcentral, tubercle-bearing keel and poorly developed peribasal keel just adaperturally; spire whorls with axially elongated, opisthocline, moderately blunt tubercles and about 10-15 weak, mostly equally-spaced, straight to slightly wavy, spiral riblets; whorl inflation slow and constant; last whorl slightly to moderately inflated, ornamented with more than 15 strong tubercles at periphery and approximately 30 spirals (some incised) that diverge on wing and become deflected adapically; tubercles end on wing; wing well-developed with adapically projecting, slightly concave spike; wing with weak, orthocline growth lines; inner surface of wing with deep primary groove adjacent to spiral ridge in line with tubercles; neck apparently reduced to small spike; aperture elongated, sublenticular with narrow notch; inner lip with moderately narrow callus."
Locus typicus: McMurdo Sound, Ross sea, Southern Ocean, Antarctica
Stratum typicum: Eocene
Geographic distribution: McMurdo Sound, Ross sea, Southern Ocean, Antarctica
Etymology: Species named after the active, majestic volcano Mount Erebus on Ross Island, which can be seen from virtually all Mount Discovery fossil sites.