Peronopora decipiens

Phylum: Bryozoa
Class: Stenolaemata
Order: Trepostomatida
Family: Mesotrypidae
Genus: Peronopora
Species: Peronopora decipiens (Rominger, 1866)

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Originally: Chaetetes decipiens
Type species: Chaetetes decipiens Nicholson, 1874 (= Chaetetes decipiens Rominger, 1866 History (Nickles & Bassler, 1900)

  • 1866 Chaetetes decipiens Rominger, Proc. Acad. Nat. Sci. Philadelphia, p. 116.
  • 1882 Peronopora decipiens Ulrich, Jour. Cincinnati Soc. Nat. Hist., V, p. 244.
  • 1874 Chaetetes frondosus (not of D’Orbigny) Nicholson, Quar. Jour. Geol. Soc. London, XXX, p. 508, pl. xxx, 2-2b.
  • 1875 Chaetetes frondosus (not of D’Orbigny) Nicholson, Pal. Ohio, II, p. 208, pl. xxii, 1-1b.
  • 1876 Chaetetes frondosus (not of D’Orbigny) Nicholson, Ann. Mag. Nat. Hist., ser. 4, XVIII, p. 91, pl. v, 11, 11a.
  • 1881 Chaetetes frondosus Quenstedt, Roehren- und Sternkorallen, p. 73, pl. cxlvi, 3-5 (not 8).
  • 1881 Monticulipora (Peronopora) frondosa (not of D’Orbigny) Nicholson, Genus Monticulipora, p. 216, figs. 46, 47, pl. v, 4, 4a, 5, 5a.
  • 1888 Monticulipora frondosa (not of D’Orbigny) James and James, Jour. Cincinnati Soc. Nat. Hist., XI, p. 17.
  • 1895 Monticulipora frondosa (not of D’Orbigny) J.F. James, Jour. Cincinnati Soc. Nat. Hist., XVIII, p. 72.

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Stratigraphic Occurrences


Geographic Occurrences

Map point data provided by iDigBio.
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Sequences (Formations)

  • C6 Sequence (Elkhorn)
  • C5 Sequence (Liberty)
  • C4 Sequence (Arnheim)
  • C3 Sequence (Mount Auburn, Corryville)
  • C2 Sequence (Bellevue)

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Identification in Hand Sample
p. decipiens

  • Zoarium Morphology: Bifoliate (usually) to more massive in shape; often fan-shaped
  • Zoecia: Circular to subpolygonal, smaller apertures than P. vera; often thick-walled (ring-like in cross-section)
  • Mesozooids: Variable to numerous, fewer than P. vera (corresponding to narrower interspaces)
  • Monticules: Low, inconspicuous (surface smooth)
  • Maculae: Central cluster of mesozooids and/or larger zooecia

Peronopora decipiens from the McMillan Formation of West Chester, Ohio (OUIP 931)

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Pachut and Anstey (2002):

  • A species with large, closely spaced, subpolygonal zooecia, high zooecial density, and a very high proportion of the zoarial surface accounted for by zooecial space. Zooecia having a large proportion of void space partitioned off by or constricted by cystiphragms. Low density of mesozooecia, a correspondingly low proportion of zoaria occupied by mesozooecial space, and simple mesozooecial shapes. Low ratio of mesozooecial to zooecial void space, with most of the space between zooecia
    occupied by single mesozooecia. Walls uniformly thin, low proportion of wall material in the zoarium, with a thin median lamina and thin walls in monticules.

McFarlan (1931)

  • P. decipiens: “Distinguished from P. vera by: fewer mesopores, correspondingly narrower interspaces. Smaller apertures. Zooarium in some specimens is almost massive.

Cumings (1907):

  • Under the description of Escharopora pavonia (E. and H.) the fact that the type of Ptilodictya pavonia d’Orb is the same species as our Peronopora decipiens (Rominger) is pointed out. This is made certain by the recently published figures of d’Orbigny’s type. These figures, which are very excellent photographic reproductions, show the type natural size, a portion of the surface also enlarged ten diameters and a section perpendicular to the surface also enlarged ten diameters. The form and surface characters of the specimen would convince any one that it is a peronopora; and no possible doubt remains after a glance at the section, which shows very clearly the median lamina and closely tabulated tubes with the series of cystiphragms, characteristic of the latter genus. It is a typical Peronopora decipiens. If one compares these figures of d’Orbigny’s type with the figures of Chaetetes pavonia on pl. 19 of the Monographie des Polypiers Fossiles, of Milne-Edwards and Haime, it is at once evident that they do not represent the same species or even the same genus. Edwards and Haime’s form is quite certainly our Escharapora pavonia, as I have pointed out under that species. Since the two are generically distinct we are at liberty to retain the name pavonia for both species, and this I have thought best to do. Rominger’s name, decipiens, must, however, now be dropped, and this species of Peronopora be known from now on as P. pavonia.
  • Peronopora pavonia d’Orb has as synonyms, besides Chaetetes decipiens Rom., C. frondosus of Nicholson, Quenstedt, and James. The latter was due to the mistake of Nicholson in wrongly interpreting the figure of C. frondosus given by Edwards and Haime.
  • The characteristics of Peronopora pavonia are briefly as follows:
    Zoarium laminar to submassive, in large examples usually more or less convolutes. One specimen in the collection has overspread the shell of Rafinesquina alternate as a large, expansion from which the laminar portion of the frond arises. The frond consists of two laminae, each with a well-defined epitheca, grown together back to back, so that the result is a frond celluliferous on both faces, and with a median, double, thin, wavy plate. Superficially, the zooecia are for the most part rounded, and more or less surrounded by mesopores. The latter are less abundant than in the species P. vera, and sometimes are comparatively few. Acanthopores are fairly abundant and of medium size, and in well-preserved specimens give a distinctly spinose appearance to the surface. In tangential sections, the zooecia are seen to have walls of medium thickness, without granules or tubules as in Monticulipora and Homotrypa. The mesopores are angular and sometimes completely isolate the zooecia. The latter are round, and only occasionally indented by the acanthopores. In longitudinal sections, the median double lamina is clearly shown, and arising from it with a very short immature region the zooecia proceed directly to the surface. The zooecia are crossed by a number of diaphragms, which are more numerous near their inner ends. Lining one (the posterior) wall of the zooecia is a series of overlapping cystiphragms. The mesopores are crossed by closely set, straight diaphragms.

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