Phylum: Bryozoa
Class: Stenolaemata
Order: Trepostomatida
Family: Amplexoporidae (Ulrich, 1889)
Cincinnatian Genera: Amplexopora, Monotrypa, Rhombotrypa

Geologic Range
Ordovician – Devonian

Common Paleoecology
Amplexoporidae was an extinct family of stationary epifaunal suspension feeders.

Description of the Family

  • Ramose to bifolate Zoarium
  • Zooecia simple, prismatic tubes, with a well-marked divisional line between adjoining tubes
  • Diaphragms present
  • Mesopores practically absent
  • Small abortive cells sometimes occur among the larger ones in the monticules
  • Acanthopores generally abundant, but may be wanting
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Treatise on Invertebrate Paleontology (1953):

  • Zoarium ramose to bifolate. Zooecia comparatively simple prismatic tubes. Acanthopores commonly abundant; mesopores absent

Bassler (1911):

  • The simplest types of the Integrata are included in this family, which, because of this simplicity as well as the practical absence of mesopores, shows the duplex character of the walls most distinctly. In the Halloporidae and Trematoporidae mesopores are almost invariably present, and the black divisional line is then only apparent where the zooecial walls are in contact. The Amplexoporidae include forms of a ramose, massive, or bifoliate growth. The zooecial tubes are simple, polygonal, with a distinct divisional line. Mesopores are practically wanting, a few abortive cells in the maculae being their only representatives. Acanthopores are generally abundant, although sometimes wanting.
  • The type genus of the family, Amplexopora, has no known representation in the Ordovician of Russia or in Black River deposits of America. It is abundantly upper Trenton and Cincinnatian formations of the Mississippi Valley. Monotrypella likewise occurs only in the formations containing faunas of supposed South Atlantic origin. Rhombotrypa is found only in the earliest Silurian deposits, where its several species are highly diagnostic fossils. I am convinced that further search will show this genus to be represented in the upper Lyckholm and Borkholm, where species associated with it in America are known.
  • The discovery of a typical species of Petalotrypa in the Middle Ordovician rocks of Russia increases the geologic range of the genus. Hitherto it has been considered typical of the upper part of the Silurian and of the Devonian.

Nickles and Bassler (1900)

  • Zoarium usually ramose or dicoidal, rarely bifoliate: zooecia simple, prismatic tubes, with a well-marked divisional line (Seen in tangential section as a fine black line) between adjoining tubes: diaphragms present: mesopores practically absent, but small abortive cells sometimes occur among the larger ones in the monticules: acanthopores generally abundant, but may be wanting.

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