Middle Ordovician – Silurian
Salpingostoma is an extinct genus of epifaunal detrivores
Identification in Hand Sample:
- Aperture expanded widely
- Shell symmetrically coiled in one plane
- Large, open umbilicus
- Surface marked with simple or sublamellose growth lines
- Adult shell having expanded, trumpet-like aperture and long, open slit extending from dorsum to slightly inside outer lip, where it is closed off. Shell generally large, involute, with wide, open umbilici revealing numerous earlier volutions; submature whorls in many cases vertically depressed, subreniform, and submature aperture at plane level with ventral umbilical shoulder; at maturity, aperture expanding abruptly to trumpetlike form, becoming tangentially oriented toward coil; submature whorls with selenizone; mature expanded whorl with long, open slit extending from dorsum to near outer sinuate apertural margin, where it is closed off; shell surface in many cases marked by transverse and radial ornament.
Treatise on Invertebrate Paleontology, Part I, Mollusca 1 (1960):
- Aperture expanded widely; slit a trema confined to whorl side, not extending onto lip, generating a selenizone; ornament growth lines.
Ulrich & Scofield (1897)
- Shell symmetrically coiled in one plane; volutions numerous, enlarging gradually, scarcely embracing, the consequence being a large, open umbilicus. Aperture abruptly expanded at maturity, trumpet-like; peristome thin, the outer portion slightly sinuate. Inner volutions with a slit band as in Bucania. This is replaced in the outer half of the last whorl by a long narrow opening or slit which, however, does not extend to the apertural expansion, but is closed some distance behind it. Surface marked with simple or sublamellose lines of growth and more or less oblique, irregular and sometimes interrupted or wavy revolving lines.