Original Description of Semiterebellum elongatum by Newton, 1922:
- "Shell elongate, subulate, depresso-convex; spire narrow, composed of about ten longitudinally deep volutions obliquely sutured, including about 3.5 smooth apical whorls, with an obtuse nucleus; body-whorl cylindrical, considerably taller than the penultimate, nearly parallel-sided; aperture forming a trigono-oval cavity, widely emarginated at the base, narrow posteriorly where it terminates on the suture with a recurved canal; labrum thickly margined, slightly excavated in the centre, but rounded, and enveloping, at the base; columella excavated, covered with a moderately wide callosity; ornamentation consists of spiral striations crossed by numerous oblique, rather obscure costations, the earlier whorls of the spire furnished posteriorly with a minute marginal collar consisting of two or three spiral lines bearing small tubercles, from which descend the more or less feeble longitudinal costae, an obscure carination exists in well preserved specimens a short distance above the suture."
Locus typicus: Ameki, Omobialla district, Nigeria
Stratum typicum: Lutetian, Eocene
Lectotype: R.B. Newton, 1992 pl. 2 fig. 15, designated by F.E. Eames, 1957, no. G.41762 (British Museum of Natural History)
Semiterebellum (Africoterebellum) elongatum in Eames, 1957, pl. 5, fig. 10a,b, Syntype no. G.41761
Semiterebellum (Africoterebellum) elongatum (Newton, 1922); Syntype; Lutetian, Eocene; Ameki, Omobialla district, Nigeria; Col. BM(NH) no. G.41767-74; Copyright BM(NH)