Parvohallopora onealli

Phylum: Bryozoa
Class: Stenolaemata
Order: Trepostomatida
Family: Halloporidae
Genus: Parvohallopora
Species: Parvohallopora onealli (James, 1875)

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Variations: Parvohallopora onealli var. communis and Parvohallopora onneali var. sigillaroides.UGA Strat Lab:Originally named Chaetetes? O’Nealli. Also called Monticulipora? onealli, Callopora onealli, Calopora onealli, and Hallopora onealli. P. onealli was regarded as a junior subjective synonym of P. nodulosa by Anstey and Perry (1973), but Brown and Daly (1985) regarded P. nodulosa as a synonym of P. ramosa. Karklins (1984) regarded P. onealli as a valid species.

Taxonomic History (Nickles & Bassler, 1900; Under Callopora onealli)

  • 1875 Chaetetes ? o’nealli James, Introd. Catal. Low. Sil. Foss., p. 2.
  • 1888 Monticulipora o’nealli James and James, Jour. Cincinnati Soc. Nat. Hist., X, p. 174.
  • 1889 Callopora onealli Miller, North American Geol. Pal., p. 296.
  • 1894 Monticulipora o’nealli J.F. James, Jour. Cincinnati Soc. Nat. Hist., XVI, p. 194.
  • Not Monticulipora (Heterotrypa) o’nealli Nicholson, Genus Monticulipora, p. 118 = Callopora onealli-sigillarioides (Nicholson).

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Stratigraphic Occurrences


Geographic Occurrences

Map point data provided by iDigBio.
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Sequences (Formations)

  • C1 Sequence (Clays Ferry/Kope: McMicken, Southgate, Economy/Fulton; Lexington/Pt. Pleasant)

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Identification in Hand Sample
E. falciformis

  • Zoarium Morphology: Ramose (branching)
  • Zoecia: Smoothly oval; may be lined; uniform in shape and well separated
  • Mesozooids: Numerous, small, angular
  • Monticules: Prominent & regularly spaced, low & rounded to sharp & conical to continues sharp ridges

Parvohallopora oneali from the Kope Formation of Cincinnati, Ohio (CMC 70518)

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Davis (1998)

  • Characteristic of P. onealli: Relatively large apertures

Karklins, 1984

  • Zoaria dendroid, having cylindrical, slender, occasionally anastomosing branches, generally without conspecific overgrowth. Endozones relatively wide. In endozones autozooecia approximately parallel to branch axis, intercalated regularly at relatively long intervals, curving gradually outward, polygonal, generally three- to six-sided in cross section. Autozooecial walls straight to slightly sinuous locally. Basal diaphragms generally absent in endozones of many zoaria, locally sparse in some autozooecia. approximately at right angles to zoarial surface, subelliptical to elliptical in cross section, aligned longitudinally. Autozooecia partly contiguous, separated by mesozooecia. Autozooecial walls relatively thin, straight, generally of uniform thickness throughout exozones. Autozooecial boundaries broadly serrated, distinct in profile, locally having indistinct pustules. Basal diaphragms common to sparse, planar to slightly curved, commonly slightly oblique to chamber axis, evenly spaced in early exozones of some autozooecia, scattered or locally absent in other autozooecia. Cystoidal diaphragms common, scattered throughout exozones; compound diaphragms sparse. Autozooecial linings sparse to absent; indistinct where present, extending for short distances distal to diaphragms, merging with laminae of cortex. Autozooecial chambers subelliptical, occasionally subcircular in cross section. Mesozooecia common, subelliptical to subcircular in cross section, partly separating autozooecia, commonly terminating in late exozones. Mesozooecial diaphragms irregular in thickness, relatively thick locally, closely and evenly spaced, commonly coalescing, and filling mesozooecia in late exozones. Maculae common to sparse, scattered, flat or slightly raised above zoarial surface, generally indistinct in cross section, consisting of clusters of mesozooecia and of one or two polymorphs larger than autozooecia.

McFarlan (1931)

  • Parvohallopora onnealli var. sigillaroides: Branches 4-5 mm in diameter, do not anastomose, bifurcate infrequently.
  • Parvohallopora onealli var. communis: “Zooarium dendroid, branches 1.5-2mm in diameter. Frequently anastomosing. Surface smooth or with inconspicuous monticules. Zooecia thin-walled, apertures oval, 5-6 in 2mm. Mesopores small, angular, and abundant. Several varieties of mesopores.

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