Oppelismilia
Duncan, 1867: 39
Type Species
Oppelismilia gemmans Duncan, 1867: 39, pl. 10, fig. 33, 34; Monotypy Duncan, 1867: 39
Type Specimen: Holotype; GSM 90 789; Verified; Dry Preserved
Type Locality: Waterloo, Larne, North of Ireland. Schlotheimia angulata ammonitic zone, Hettangian, Early Jurassic.
Holotype housed at the Geological Survey Museum, London, United Kingdom
Classification
Diagnosis
Solitary, trochoid with shallow calice. Septa numerous, differentiated in length into five size orders, ordered in regular systems, compact, built of uniform septal spines. The S1 septa enter to the axial cavity; the septa S5 are rudimentary. Distal septal margin is denticulated with tips of septal spines, septal sides are marked with trajectories of the spines; the surface of the spines is covered with minute granulation typical of Stylophylidae. Endotheca is dissepimental. Wall epithecal.
Description
The species was well described and illustrated based on the holotype specimen by Flügel 1964: 337, text-fig. 1-3, and L. Beauvais 1976: 70, text-fig. 35, pl. 14, fig. 4, pl. 15, fig.3. Of special documental value are the figures in Flügel 1964: text-figs. 2, 3, and Beauvais 1976: pl. 15:3, presenting peels of the sections in the distal part of the corallum. However, in these authors’ interpretations, synapticulae are present among skeletal elements, which remains a not confirmed information. The so called “calicular gemmation” in Duncan 1867: 39 and in explanation to the plate 10, named also “budding by rejuvenation” in Beauvais 1976: 70, is to be re-interpreted as a phenomenon of a partial regeneration, than budding.
Comparisons
From solitary and trochoid Stylophyllopsis having septa made of septal spines, Oppelismilia differs in uniform shape and size of the spines. From Haimeicyclus Alloiteau, 1957, well presented in Stolarski and Russo 2002: fig. 2 and 5, similar in the structure and micromorphology of septal spines, Oppelismilia differs in trochoid, not patellate shape of corallum. Among Early Jurassic corals, Montlivaltia sinemuriensis de Fromentel, 1862, described from the Sinemurian of the Côte d’Or, has all features of Oppelismilia, as can be observed on the specimens from the type series: coll. de Fromentel 1862, pl. 7 fig. 21, 23, 25 housed at the Museum d'Historire Naturelle in Basel, Switzerland.
Remarks
Three nominal species are known.
Distribution
- Western Europe; Early Jurassic
This page has been in preparation since 19-Aug-2009 16:18
This version was contributed by Ewa Roniewicz on 26-Nov-2010 15:05.
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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