Amplexopora

Classification
Phylum: Bryozoa
Class: Stenolaemata
Order: Trepostomatida
Family: Amplexoporidae
Genus: Amplexopora Ulrich, 1882
Cincinnatian Species: Amplexopora robusta, Amplexopora septosa

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Synonyms: Acanthotrypella Vinassa de Regny, 1921Type Species: Atactopora septosa (Ulrich, 1879) see Boardman 1960 (Bryozoa.net)
History: (Nickles & Bassler, 1900)

1882 Amplexopora Ulrich, Jour. Cincinnati Soc. Nat. Hist., V, p. 154.
1883 Amplexopora Foord, Contr. Micro-Pal. Cambro.-Sil., p. 15.
1889 Amplexopora Miller, North American Geol. Pal., p. 291.
1890 Amplexopora Ulrich, Geol. Surv. Illinois, VIII, pp. 377, 450.
1896 Amplexopora Ulrich, Zittel’s Textb. Pal. (Engl. Ed.), p. 278.
1897 Amplexopora Simpson, Fourteenth Ann. Rep. State Geologist New York for the year 1894, p. 577.

Species found in the Cincinnatian (Bryozoa.net)

Amplexopora ampla (Ulrich & Bassler, 1904)
Amplexopora columbiana (Ulrich & Bassler, 1904)
Amplexopora cylindracea (Ulrich & Bassler, 1904)
Amplexopora discoidea (Nicholson, 1874)
Amplexopora filiasa (d’Orbigny, 1850)
Amplexopora parva (Utgaard & Perry, 1964)
Amplexopora persimilis (Nickles, 1905)
Amplexopora petasiformis (Nicholson, 1881)
Amplexopora petasiformis welchi (James, 1882)
Amplexopora pumila (Cummings & Galloway, 1913)
Amplexopora pustulosa (Ulrich, 1890)
Amplexopora robusta (Ulrich, 1882)
Amplexopora septosa (Ulrich, 1879)
Amplexopora variabilis (Ulrich, 1890)

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Geologic Range
Ordovician

Common Paleoecology
Amplexopora is a genus of extinct stationary epifaunal filter feeders

Identification in Hand Sample:

Zoarium Morphology: Ramose, frondose, discoidal, massive, or encrusting; 5-10mm diameter
Zoecia: Prismatic, polygonal; Some species have zooecial linings
Mesozooids: Few to none
Monticules: None (Or very low)
Maculae: Composed of larger zooecial apertures & some mesopores

Geographic Occurrences

Species Differentiation

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Steven Holland (UGA Strat Lab, 2013):

Thin section information: Styles abundant: Some located in zooecial corners and extend throughout endozone. Others are located along zooecial walls and extend only partly through endozone; these often inflect zooecial walls into irregular pelatoid shapes; Cystoidal diaphragms and cystiphragms common in many species

Hannah Brame pers. comm. (2013):

A. septosa can be distinguished from A. robusta by its thicker cell walls, and the presence of mesopores

Treatise on Invertebrate Paleontology, Part G (1953):

Ramose; Zooecia with complete diaphragms. Acanthopores numerous.

Nickles & Bassler (1900):

Zoarium ramose, discoidal, or massy; zooecia prismatic, with diaphragms; acanthopores always present, variable in size and number

Foord (1883):

Ramose, free or incrusting. Cellular structure as in Monotrypella, excepting that more or less numerous spiniform tubuli are developed, which sometimes completely encirlcle the tubes./li>

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A. robusta

A. septosa