Type Species: Eridotrypa mutabilis (Ulrich, 1893)
History: (Nickles & Bassler, 1900)
- 1890 Batostomella (in part) Ulrich, Geol. Survey. Illinois, VIII, pp. 375, 432.
- 1893 Eridotrypa Ulrich, Geol. Minnesota, III, p. 264.
Species found in the Cincinnatian of OH, KY, IN (Bryozoa.net)
- Eridotrypa aedilis (Eichwald, 1855)
- Eridotrypa briarea (Nicholson, 1875)
- Eridotrypa libana (Safford, 1869)
- Eridotrypa minor (Ulrich, 1893)
- Eridotrypa mutabilis (Ulrich, 1893)
- Eridotrypa pelliculata (Fritz, 1926)
- Eridotrypa sadievillensis (Karklins, 1984)
- Eridotrypa trentonensis (Nicholson, 1881)
- Although there are unconfirmed reports of this genus from the upper Cincinnatian, it is probably limited to the basal Cincinnatian (lower Kope and Clays Ferry) and the underlying Lexington Limestone.
- C5 Sequence (Lower Whitewater, Waynesville)
- C1 Sequence (Clays Ferry/Kope, Lexington/Pt. Pleasant)
- Zoarium Morphology: Ramose and slender
- Zoecia: Oval, oblique; Thick-walled; Styles numerous, small
- Mesozooids: Common/variable
Steven Holland (UGA Strat Lab, 2013):
- Eridotrypa is ramose and slender. Zooecial openings are oval and zooecia meet the surface obliquely. Walls are subpolygonal, and zooids do not display a repeated arrangement. Large zooids present in center of endozone, and zooids distinctly narrow in outer endozone. Diaphragms common near bend and inner exozone. Mesozooids common at wall junction and appear at base of exozone. Styles are numerous.
- Ross (1967) placed the genus Eridotrypa alongside her own genera Lamottopora Ross, 1963 and Newportopora Ross, 1967, in the family Aisenvergiidae Dunaeva, 1964. She argued that these genera have a similar budding pattern with long zooecia having larger diameters in the axial part. The family Aisenvergiidae contained originally three genera: Aisenvergia Dunaeva, 1964, Volnovachia Dunaeva, 1964 and Polycylindricus Boardman, 1960. However, these genera are characterised by completely different wall structure (predominantly merged, without visible zooecial boundaries), and presence of exilazooecia instead of mesozooecia. Therefore, Astrova (1978) criticized the placement of Eridotrypa, Lamottopora, and Newportopora in the family Aisenvergiidae. She placed Eridotrypa in the family Trematoporidae, which appears justified because Eridotrypa and Trematopora share serrated wall structure and endozonal zooecial diameters larger than those in exozone.
- Zooarium ramose with more or less oblique, thick walled zooecia. Acanthopores small, few or wanting. Mesopores variable.
- Zoarium ramose, branches slender; zooecia more or less oblique, thick-walled, and intersected by diaphragms, which are most numerous and most closely set in the earlier portion of the short, mature region; mesopores sometimes numerous, sometimes few, with closely set diaphragms; acanthopores small, few, or wanting.
- Genotype.—Eridotrypa mutabilis Ulrich. Middle Ordovician (Black River) of the Mississippi Valley.
- All of the American Black River species of Eridotrypa are represented in the several formations of division D, and in the Wesenberg limestone.
Nickles & Bassler (1900):
- Eridotrypa Ulrich: Zoarium ramose, branches slender; zooecia more or less oblique, thick-walled, and intersected by diaphragms, which are most numerous and most closely set in the earlier portion of the short mature region; mesopores sometimes numerous, sometimes few, with closely set diaphragms; acanthopores small, few, or wanting.