Parvohallopora dalei

Phylum: Bryozoa
Class: Stenolaemata
Order: Trepostomatida
Family: Halloporidae
Genus: Parvohallopora
Species: Parvohallopora dalei (Milne Edwards & Haime, 1851)

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

  • 1851 Chaetetes dalii Milne-Edwards & Haime, Pol. Foss. Terr. Pal., p. 266, pl. xix, 6, 6a.
  • 1854 Monticulipora dalii Milne-Edwards & Haime, British Foss. Corals, p. 265.
  • 1860 Monticulipora dalii Milne-Edwards & Haime, Hist. Nat. des Corall., III, p. 277.
  • 1881 Monticulipora (Heterotrypa) ramosa var. dalei Nicholson, Genus Monticulipora, p. 115, fig. 19, C, D, pl. ii, 4.
  • 1882 Callopora dalei Ulrich, Jour. Cincinnati Soc. Nat. Hist., V, p. 252. .
  • 1888 Monticulipora ramosa var. dalei James and James, Jour. Cincinnati Soc. Nat. Hist., XVI, p. 205.
  • 1894 Monticulipora ramosa var. dalei J.F. James, Jour. Cincinnati Soc. Nat. Hist., XVI, p. 205.
  • 1874 Chaetetes approximatus Nicholson, Quar. Jour. Geol. Soc. London, XXX, p. 502, pl. xxix, 3, 3a.
  • 1875 Chaetetes approximatus Nicholson, Pal. Ohio, II, p. 193, pl. xxi, 3.
  • 1883 Monticulipora approximatus (Van Cleve) Hall, Twelfth Ann. Rep. Indiana Geol. Hat. Hist., p. 250, pl. xi, 6.

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Stratigraphic Occurrences


Geographic Occurrences

Map point data provided by iDigBio.
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Sequences (Formations)

  • C2 Sequence (Fairview: Fairmount)

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Identification in Hand Sample
E. falciformis

  • Zoarium Morphology: Ramose (branching); 3-8 mm in diameter
  • Zoecia: Smoothly oval; may be lined; uniform in shape and well separated
  • Mesozooids: Numerous, small, angular; in some cases, completely isolating zooecia
  • Monticules: Prominent & regularly spaced, sharp & conical to continues sharp ridges; several mm apart; characterized by more numerous mesopores

Parvohallopora dalei from the Fairview Formation of East Fork Lake, Ohio (CMC 69949)

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MacFarlan (1931)

  • Distinguished from H. ramosa by more slender zoarium and smaller monticules

Parks & Dyer (1921):

  • The description given by Nicholson for Chaetetes approximatus which is regarded as identical with Hallopora dalei, is as follows:
    Corallum composed of cylindrical stems, from one and a half to nearly three lines in diameter, dividing dichotomously at short intervals. Corallites tolerably thick-walled, oval, sub-circular, or polygonal in shape, some eight to ten in the space of one line, often with excessively minute corallites interspersed amongst them, though these are rarely as abundant as in the preceding forms (Chaetetes dalei and Chaetetes rugosus), and may be nearly absent. Surface exhibiting a number of small conical or somewhat transversely elongated eminences, which are very slightly elevated above the general surface. These eminences are placed in irregular diagonal rows, separate about half a line transversely and two-thirds of a line measured vertically, and they are either solid at their summits, or carry a few excessively small cylindrical tublii, with or without one or more of the ordinary corallites.

Nicholson (1881):

  • Obs. Not having had the opportunity of examining the original specimens upon which Milne-Edwards and Haime founded their Chaetetes Dalii (Pol. Foss., p. 266, Pl. XIX. figs. 6, 6a, 1851), I cannot be absolutely certain that I have correctly identified it. Judging, however, from their figures and descriptions, I have little doubt that the form which I described as Chaetetes approximatus (Quart. Jour. Geol. Soc., vol. xxx. p. 502, Pl. XXIX. figs. 3, 3a, 1874) is really the same. Accepting this conclusion, the differences and resemblances between M. ramosa, D’Orb., and M. Dalii, E. and H., may be briefly stated as follows: As regards external characters, M. Dalii precisely agrees with the type-form of M. ramosa, D’Orb., except that the monticules are much reduced in size, and that the interstitial tubuli are sometimes not quite so conspicuous or numerous. The monticules (Pl. II, fig. 4) are no longer boldly prominent or conical, but are much smaller, and in general either gently rounded or somewhat elongated transversely. With the above slight external difference, there is associated a complete agreement in internal structure, both tangential and longitudinal sections (fig. 19, C and D) showing features precisely similar to those exhibited by corresponding sections of typical examples of M. ramosa, D’Orb. U cannot doubt, therefore, that as in the case of the co-called M. rugosa, E. and H., we have to deal in M. Dalii, E. and H., with nothing more than well-marked variety of M. ramosa, D’Orb.

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