Nannotax3 - ntax_Farinacci

Original descriptions of taxa - also emended descriptions for a few taxa. For coccolithophores, and many calcispheres, these are pages from the Farinacci & Howe Catalog of Calcareous Nannofossils. In other cases (e.g. non-calcifying haptophytes) the data is directly compiled on this site. The "Catalogue of Calcareous Nannofossils" was originally compiled by Prof A. Farinacci 1969-1989, since 2000 it has been updated and extended by Richard Howe - see The Farinacci and Howe Catalog - an Introduction.
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Citation: Corannulus Stradner 1962

Type species: Corranulus germanicus Stradner, 1962

Farinacci catalog page (& compiler): 1051

Von fossilen Kalkflagellaten herrührende grossporige Gehäuseelemente von unregelmässig ovalem oder zahnkranzartigem Umriss. Von einem schwach ovalen bis annähernd kreisrunden zentralen, erhöhten Ring nehmen 7- 12 in zentrifugaler Richtung steil abfallende radiale Stege ihren Ausgang. Ihre Ansatzstellen sind als erhöhte Rippen auch bei stark reduzierten Arten erhalten. Die peripheren Enden der Stege können frei sein (Corannulus germanicus n. sp.) oder durch Bögen miteinander verbunden sein (Corannulus arenarius n. sp.). Die grosse zentrale Öffnung, welche an den Ansatzstellen der Stege leicht ausgebuchtet ist, ist in letzterem Falle von einem Kranz von abgerundet dreieckigen oder trapezförmigen Fenstern umgeben.

Remarks: Diese Gattung von Coccolithen scheint durch starke Reduktion grossporiger Vorläuferformen ex gr. Discolithus macroporus DEFLANDRE entstanden zu sein. Da die beiden neuen Arten Corannulus arenarius und Corannulus germanicus schwer in der Gattungsdiagnose von Discolithus KAMPTNER, 1955 unterzubringen waren, wurde für sie der neue Gattungsname Corannulus gewählt.

Translation (Google Translate 2023)
Large-pored shell elements originating from fossil calcareous flagellates with an irregular oval or toothed ring-like outline. From a slightly oval to almost circular central, elevated ring, 7-12 radial ridges descend steeply in a centrifugal direction. Their attachment points are preserved as raised ribs even in greatly reduced species. The peripheral ends of the ridges can be free (Corannulus germanicus n. sp.) or connected by arches (Corannulus arenarius n. sp.). In the latter case, the large central opening, which is slightly indented at the points of attachment of the struts, is surrounded by a ring of rounded triangular or trapezoidal windows.

Remarks: This genus of coccoliths seems to have evolved through strong reduction of large-pored precursor forms ex gr. Discolithus macroporus DEFLANDRE. Since the two new species Corannulus arenarius and Corannulus germanicus were difficult to accommodate in the generic diagnosis of Discolithus KAMPTNER, 1955, the new generic name Corannulus was chosen for them.

References:

Stradner, H. (1962). Über neue und wenig bekannte Nannofossilien aus Kreide und Alttertiär. Verhandlungen der Geologischen Bundesanstalt (Wien). 2: 363-377. gs

				Corannulus arenarius Stradner 1962 = Peritrachelina arenaria
				Corannulus germanicus Stradner 1962 = Corannulus germanicus
				Corannulus horridulus Bown 2005 = Corannulus horridulus
				Corannulus tauricus Vasilyeva & Musatov 2023 = Corannulus tauricus

CATALOG - Corannulus

References:

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