Hallopora andrewsi

Phylum: Bryozoa
Class: Stenolaemata
Order: Trepostomatida
Family: Halloporidae
Genus: Hallopora
Species: Hallopora andrewsi (Nicholson, 1874)

[accordions title=”” disabled=”false” active=”1″ autoheight=”false” collapsible=”true”] [accordion title=”Taxonomic Details”]
Taxonomic History (Nickles & Bassler, 1900; Under Callopora andrewsi)

  • 1874 Chaetetes pulchellus (not of Milne-Edwards & Haime) Nicholson, Quar. Jour. Geol. Soc. London, XXX, p. 503, pl. xxix, 5-5b.
  • 1875 Chaetetes pulchellus (not of Milne-Edwards & Haime) Nicholson, Pal. Ohio, II, p. 195, pl. xxi, 5, 5a.
  • 1881 Monticulipora (Heterotrypa) andrewsi Nicholson, Genus Monticulipora, p. 128, fig. 21, pl. v, 1, 1a.
  • 1882 Callopora andrewsi Ulrich, Jour. Cincinnati Soc. Nat. Hist., V, p. 252.
  • 1883 Monticulipora andrewsii (Van Cleve) Hall, Twelfth Ann. Rep. Indiana Geo. Nat. Hist., p. 249, pl. xi, 9.
  • 1888 Monticulipora andrewsii James and James, Jour. Cincinnati Soc. Nat., Hist., X, p. 178.
  • 1894 Monticulipora andrewsii J.F. James, Jour. Cincinnati Soc. Nat. Hist., XVI, p. 200.

Note: Probably all species referred to as Hallopora from the type Cincinnatian are actually Parvohallopora. (Steven Holland, UGA Strat Lab 2013)
[/accordion] [/accordions]

Stratigraphic Occurrences


Geographic Occurrences

Map point data provided by iDigBio.
[accordions title=”” disabled=”false” active=”1″ autoheight=”false” collapsible=”true”] [accordion title=”Stratigraphic Description”]
Sequences (Formations)

  • C3 Sequence (Corryville)
  • C2 Sequence (Bellevue)

[/accordion] [/accordions]

Identification in Hand Sample

  • Zoarium Morphology: Ramose; 6-12 mm
  • Zoecia: 7 in 2mm; surrounded by variable number of mesopores
  • Mesozooids: Numerous
  • Monticules: Low and rounded
  • Maculae: Composed of larger apertures, with more numerous mesopores

Hallopora andrewsi from the McMillan Formation of Georgetown, Ohio (OUIP 876)

[accordions title=”” disabled=”false” active=”1″ autoheight=”false” collapsible=”true”] [accordion title=”Published Description”]
McFarlan (1931)

  • Zooarium ramose, 6-12 mm in diameter. Surface typically with low, rounded monticules composed of larger apertures and more numerous mesopores. Zooecia 7 in 2 mm, surrounded by a variable number of angular or subcircular mesopores. Tabulations of zooecia variable.

Cumings (1907):

  • “Corallum variable in form, usually of subcylindrical branches, which have a diameter of from 2 to 6 lines, sometimes forming flattened and expanded subpalmate fronds, sometimes inosculating. Corallites thin-walled, polygonal, unequal in size, about eight of the average ones occupying the space of 1 line. Surface exhibiting rounded or somewhat stellate groups of larger corallites, of which two or three occupy the space half a line, and which sometimes have very minute intermediate tubuli between them. These groups of larger corallites generally comprise from five to seven individuals, and they are placed about 1 line apart; they are very slightly or not at all elevated above the general surface so that there are no conspicuous tubercles.
  • “The characters of this species are so well marked as to render its recognition very easy, even in small fragments.” – Nicholson, loc. cit.
  • Internally this species exhibits very beautifully the peculiar structure of the genus Callopora. Toward the surface, the walls are much thickened and ring-like and are separated from each other by a set of small rounded mesopores. In longitudinal sections, the zooecia and mesopores are seen to be crossed by a well-developed series of straight diaphragms, which are very close together in the mesopores.

[/accordion] [/accordions]