Heterotrypa parvulipora

Classification
Phylum: Bryozoa
Class: Stenolaemata
Order: Trepostomatida
Family: Heterotrypidae
Genus: Heterotrypa
Species: Heterotrypa parvulipora (Ulrich & Bassler, 1904)

Stratigraphic Occurrences

h.parvulipora_strat

Geographic Occurrences

		
Map point data provided by iDigBio.

Stratigraphic Description

Sequences (Formations)

  • C1 Sequence (Cynthiana)

Identification in Hand Sample

  • Zoarium Morphology: Large, frondescent
  • Zoecia: Polygonal to circular, thick walled; smaller than H. frondosa; acanthopores small and few
  • Mesozooids: Variable, less abundant than H. frondosa
  • Monticules: Small, slightly raised monticules, surface smooth

Heterotrypa parvulipora from the McMillan Formation of Crestview Hills, Kentucky (OUIP 590)

Published Description

McFarlan (1931)

  • Large, frondescent species distinguishable from H. frondosa by smaller zooecia (10 in 2mm), smaller and generally fewer acanthopores, fewer mesopores, surface smooth with slightly raised maculae.
  • Diagnosis: Larger and very frondescent. Distinguishable from H. frondosa by: 1. Smaller zooecia (10 in 2mm); 2. Smaller/fewer acanthopores; 3. Fewer mesopores; 4. Smooth surface with only slightly raised maculae

Nickles (1905):

  • Zoarium forming large, flabellate expansions from 10 to 15 mm. in thickness. Surface smooth; maculae not a prominent feature, often scarcely distinguishable. Apertures small, angular, thin-walled, about 10 in 2 mm. In the immature region the zooecia have thin, somewhat wavy walls and diaphragms from one to three times their diameter apart; in the mature regions the walls are thickened and diaphragms are much more closely set, becoming as frequent as two to a tube diameter. Mesopores, few. Acanthopores small, generally few, but sometimes each angle of junction is occupied by one.

Ulrich & Bassler (1904):

  • This fine species is very abundant in the Catheys limestone at a number of localities in Tennessee and is related to the type of the genus H. frondosa which is probably a descendant.
  • The type specimen of H. parvulipora is a large flabellate expansion 200 mm. in height and measuring the same at its broadest part. Frond varying from 10 to 15 mm. in thickness. Surface smooth, maculae not a prominent feature, often scarcely distinguishable. Zooecia small, angular, thin-walled, 10 in 2 mm. Mesopores few. Acanthopores small, generally few, but sometimes each angle of junction is occupied by one.
  • In the immature region, the zooecial tubes have thin wavy walls and are crossed by diaphragms at distances varying from one to three tube-diameters. The walls become thickened in the mature regions and here also diaphragms become as frequent as two to a tube-diameter. Tangential sections show especially well the structure of the walls and the distinct, clear-cut acanthopores.
  • Compared to H. frondosa (D’Orbigny), H. parvulipora has smaller zooecia, fewer mesopores, smaller and generally fewer acanthopores. As already stated, specimens are abundant, but care must be exercised in distinguishing them from an associated new species of Homotrypa which resembles them very greatly in external features. Internally the Homotrypa is of course quite distinct.