Allocoenia
Etallon, 1859 : 477
Corals described also under the names of Astrocoenia Milne Edwards and Haime, 1848, Actinastrea d’Orbigny, 1849, Stephanocoenia d’Orbigny, 1850 and Stephanastrea Etallon, 1864.
Type Species
Allocoenia trochiformis Etallon 1859: 478; Original Designation Etallon 1859: 478
Type Specimen: Neotype; ; Not Traced; Dry Preserved
Type Locality: Valfin, France. Kimmeridgian
Original specimen has been lost. Alloiteau 1957:61 chose a neotype.
Classification
Diagnosis
Cerioid, corallites about 2 mm in diameter, polygonal. Septa subconfluent and nonconfluent. Symmetry hexameral. Septa in 3 size orders: S1 reach the columella, S2 with elongated paliform lobes approaching to the columella, S3 regularly anastomosing with S2. Septal sides with sharp, densely arranged granules. Columella styliform. Endotheca subtabular. Wall septothecal. Increase by intercalicular budding.
Description
Described by Koby, 1885: 301, pl. 85, fig. 1-3, and in 1888: 554, pl. 130, fig.11 with discussion on colony and corallite structure. Alloiteau 1957: 61 re-described the type species based on the neotype, re-defined the genus, and discussed its affiliation to the family Actinastraeidae. Description of A. trochiformis from Poland was based on thin sections in Roniewicz 1976: 36, pl. 1, fig. 6a-c.
Comparisons
In cerioid type of colony, small corallites, styliform columella the genus is the most similar to Stephanastrea Etallon, 1864 but differs from it in having thick paliform lobes in front of the S2 septa, regular anastomosis of S2 and S3 septa, and hexameral symmetry.
Remarks
Five nominal Jurassic species.
Distribution
- Western Europe; Late Jurassic
- Central Europe; Late Jurassic
Known in the Oxfordian-Kimmeridgian of EuropeThis page has been in preparation since 07-May-2009 07:18
This version was contributed by Ewa Roniewicz on 19-Nov-2010 15:13.
Page authors are: Ewa Roniewicz. Please contact the editor if you would like to contribute to the diagnosis of this taxon.
The editor is: Bernard Lathuilière
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