Referred to as: Cyclonema (Holopea), Macrocheilus (Holopea)
- 1847 Holopea Hall, Pal. N.Y., vol. i, p. 169.
Middle Ordovician – Devonian
Holopea is an extinct genus of stationary epifaunal suspension feeders
Identification in Hand Sample:
- Whorls expand slowly
- Deep sutures
- Moderate spire, open umbilicus
- No ornamentation, but final whorl may have coarse rounded ribs
- Growth lines straight and orthocone
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Fossils of Ohio (1996):
- Whorls slowly expanding
Boucot & Yochelson (1966):
- This identification of Holopea sp. is based on a single broken external mold. The shell is globose and low-spired. This form may have had a narrowly phaneromphalous umbilicus. Growth lines are straight and nearly orthocline. Though the specimen is well preserved, its species cannot be identified because it is incomplete.
Treatise on Invertebrate Paleontology, Part I, Mollusca 1 (1960):
- Whorls rounded, in some species disjunct; sutures deep; final whorl may bear coarse rounded ribs.
- Holopea furnished some of the species which may be included in this group, but before these are discussed the genus itself may be considered. Holopea was briefly discussed by McCoy as follows: “Shell spiral, elongate, slender, of numerous gradually increasing whorls, generally crossed by slightly arched striae; mouth circular, with the peristome entire; base rounded, with or without a minute umbilicus.”
- Rounded whorls, slightly impressed, forming a moderate spire with open umbilicus. No ornamentation.
Ulrich & Scofield (1897):
- Though we have given considerable study to the matter, we prefer not to commit ourselves at present to a description of the generic characters. We may say, however, that Holopea, as now used, embraces much that does not belong here. Indeed, some of the following species doubtless will be removed when the contents of the genus are finally revised. Most diverse affinities are indicated by different sets of species, some evidently being true Littorinidae, others are related to Cyclonema and Strophostylus, another set to Platystoma, while a few are difficult to place.
- Shells conical, ventricose, more or less oblique or nearly direct; aperture round ovate; margin entire; surface marked by simple fine curved striae, or cancellated. The shells constituting this genus have the general form of Turbo or Paludina, differing somewhat in the form of the aperture. They are distinguished from the Pleurotomaria by the absence of a slit in the margin of the aperture, or of angular bending in the striae upon the surface, as well as being generally more ventricose, and the volutions more regularly rounded. There are also some other reasons for separating these shells from the genus Turbo, which probably had not come into existence at so early a period; since most of those heretofore referred to it, and other allied genera, have been subsequently discovered to belong to distinct genera, and to posses reliable characters for their separation. As examples of these, may be instanced Murchisonia and Loxonema, which have become well known within a short time, and generally distinguishable from other genera by obvious characters. The two forms in the Calciferous sandstone, referred to the genus Turbo, probably belong to the genus here proposed.