Early Ordovician – Silurian
Liospira is an extinct genus of extinct facultatively mobile epifaunal suspension feeders
Identification in Hand Sample:
- Sublenticular and subconical shape
- Smooth and rounded edges
- Sutures between whorls are small and very close
- Aperture has a deep notch, but no band
- Convex selenizone
- No surface ornamentation
- Shell small
- Moderately small (up to 18 mm in diameter), lenticular (about two times wider than high), cryptomphalous, sharp angular periphery slightly above mid-whorl apparently
bearing narrow selenizone; upper shell surface broadly convex and slightly gradate, upper surface of whorl edge slightly up- turned; no sutures visible; below angular periphery shell curves
convexly around base to umbilicus; no previous whorls visible; outer aperture not preserved, columellar lip thickened.
Treatise on Invertebrate Paleontology, Part I, Vol. 1 (1960):
- Surface glossy, without ornament; selenizone convex, forming periphery but largely on upper side; cryptomphalous.
- Shell sublenticular, subconical, sharply rounded at the periphery, almost smooth. Suture close, scarcely distinguishable. Umbilicus often filled by reflected inner lip. Aperture deeply notched, band obscure. Surface markings of growth lines and spirals
Ulrich & Scofield (1897):
- Shell sublenticular, the spire low, depressed conical, almost smooth, the sutures very close, scarcely distinguishable; volutions subrhomiboidal in section, flat, gently convex or slightly concave above, sharply rounded at the periphery, convex below, and not infrequently angular at the edge of the umbilicus. The latter is usually present but may be filled entirely by an extension from the inner lip, in other cases it may be open during the younger stages only. Aperture deeply notched; band scarcely distinguishable as such, wide, situated on the narrow outer edge of the whorls though chiefly upon the upper side. Surface markings very delicate, rarely preserved, consisting generally of exceedingly fine transverse lines bending strongly backward on the apical side of the peripheral band over which they continue with little interruption to sweep sharply forward again on the lower side. Faint revolving lines occasionally observed.