Species: Homotrypa norwoodi (Nickles, 1905)
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Map point data provided by iDigBio.
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- C1 Sequence (Clays Ferry/Kope))
Identification in Hand Sample
- Zoarium Morphology: Frondose, branching; rounded or compressed branches; 3-6 mm thick, 2-12 mm wide
- Zoecia: Polygonal apertures; moderate thick walls; acanthopores small, numerous
- Mesozooids: Absent, except in monticules
- Monticules: Surface covered with small, conical monticules
- Maculae: Larger cell apertures
Homotrypa norwoodi from the McMillan Formation of Crestview Hills, Kentucky (OUIP 958)
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- As originally described this species, referred to Homotrypella, forms rounded or compressed branches, 3-6 mm. thick and 2-12 mm. wide. Surface covered with small, conical monticules. Apertures polygonal, walls of only moderate thickness, and averaging 12 in 2 mm. Mesopores absent except in the monticules which are composed of zooecia slightly larger than the average. Acanthopores small, very numerous, three to five surrounding, and commonly indenting the apertures. Diaphragms widely spaced in the (im.). Cystiphragms small, numerous in the (m), accompanied by an equal number of diaphragms. The types are from Pleasant Valley, Carlisle County.
Numerous specimens of a very similar form have been collected by the writer from exposures of the upper Cynthiana east of Winchester and other localities which differ from the species as described above in the more robust growth, attaining a thickness of 8 mm., and in the absence of acanthopores. The zooecia are a little smaller averaging about 10 in 2 mm. In spite of the difference in development of acanthopores the writer regards the two as specifically the same. In both the original specimens and in those just mentioned the meagre development of mesopores does not suggest the genus Homotrypella.
A common and characteristic fossil of the upper Cynthiana.
- Zoarium ramose, branching at variable intervals; consisting of rounded or compressed branches from 3 to 6 mm. thick and from 4 to 12 mm. wide. Surface with small, conical monticules, about one-half mm. in diameter at their bases, and 2 mm. or somewhat less apart measuring from summit to summit. Apertures subpolygonal, all of about the same size, from 12 to 14 in 2 mm., often indented by the numerous small acanthopores. No mesopores detected. Zooecia with thin, somewhat flexuous walls, and rather distant diaphragms in the immature region; they bend rather abruptly to the mature region, where they have their walls lined by a linear series of small, overlapping cystiphragms. In this region also diaphragms are from 2 to 4 times their diameter apart.