Middle Ordovician – Middle Devonian, ?Mississippian
Cornulites is an extinct genus of stationary epifaunal suspension feeders.
Identification in Hand Sample:
- Solitary animal inhabiting one long tube.
- Promint external rings in adult stages and longitudinal striae in gerontic forms.
- Thick cellular walls.
- Tubes up to 80mm in length and 20 mm at aperture.
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- Cornulites has traditionally been considered a polychaete tubeworm, but its internal structure suggests that it is allied with the tentaculitids, which may both belong within the phoronid worms (Vinn and Motus, 2008)
Herringshaw et al.(2006):
- The genus Cornulites, with the type species C. serpularius Schlotheim, 1820, from the Silurian of Gotland, comprises annulated, conical or tubular calcite shells, often found attached to the hard parts of other organisms. No consensus has ever been reached over the zoological afﬁnities of the taxon, and no examples of soft-part preservation are known: detailed examination of shell structures and growth patterns provide the only means of assessing its systematic position. Using transverse and longitudinal thin sections of C. serpularius Vine, 1882, and C. cellulosus sp. nov., from the Much Wenlock Limestone Formation of England, the shell structure of Cornulites is shown to be lamellar, but with conspicuous internal chambers (camerae) at the apical end of the shell and, particularly in C. cellulosus, numerous smaller vacuities (cellulae) between the lamellae in the apertural shell region. Growth of the shell was by the secretion of low-magnesian calcite increments within one another, giving a cone-in-cone structure, with the prominent development of cellulae in C. cellulosus probably a constructional feature relating to an uprightlife position.
Treatise on Invertebrate Paleontology, Part W, Vol. 1 (1962):
- Animal solitary, inhabiting a relatively long tube. Prominent external rings in adult stages and prominent longitudinal striae in gerontic forms. Cellular walls very thick. Tubes reach a length of 80mm, and a diameter of 20mm at aperture.