Middle Cambrian – Early Triassic
Conulariida is an extinct order of stationary epifaunal suspension feeders
Characteristics of the Order
- Conical, pyramidal pelagic shells
- May or may not become contracted toward the mouth
- Shells smooth, longitudinally divided and transversely furrowed
Fossils of Ohio (1996):
- Conulariids are extinct marine organisms characterized by an elongate, four-sided, pyramidal exoskeleton of phosphatic composition. Their unique exoskeleton, which is commonly whitish, black, blue, or multicolored because of its phosphatic nature, makes them among the most distinctive and interesting of Ohio’s fossils. The exoskeleton has an aperture (opening) at the widest end, and tapers to a closed, slightly rounded apex. The apex is rarely preserved. As viewed externally, each of the four sides, or faces, is crossed by numerous pairs of transverse, curved, narrow ridges that meet at a distinct longitudinal midline. On the inside of the exoskeleton along the midline of some species, a distinct longitudinal thickening, called a carina, is present. Ridges seemingly are formed by local thickenings in the layers of the exoskeleton. These thickenings, which have been called rods, probably provided some support to an otherwise thin, and rather flexible, exoskeleton or integument. In some species, the rods are ornamented with nodes or spines. If spines are present, small crests between and at right angles to the ridges may be evident externally. Adjacent faces meet at a longitudinal groove called a corner groove.
Miller & Gurley (1896):
- This name is proposed to receive conical and pyramidal, pelagic shells, which may or may not have been contracted toward the mouth, but the texture of which is always horny with lime phosphate. The shells during the lives of the animals were flexible. They are smooth, or longitudinally divided and transversely furrowed. There are no muscular scars on the casts or on the shells. All belong to the palaeozoic rocks.