Amphiastrea
Etallon, 1859, p. 500/100
Type Species
Amphiastrea basaltiformis Etallon, 1859 p.501; Monotypy
Type Specimen: Lectotype; MHNG GEPI 61503; Verified; Dry Preserved
Type Locality: "Dicératien" (Kimmeridgian) Valfin/St Claude, France.
The lectotype was selected in (Kühn 1939) p. 184 as illustrated by Koby (1888) and coming from the Etallon's collection. Beauvais (1964) mentioned a "holotype" that corresponds in fact to the lectotype selected by Kühn. Following a mistake induced by an illustration of a non type specimen by Alloiteau (1950) and a long and disputable exegesis of Etallon’s text in Alloiteau (1957), it is commonly and erroneously said that A. basaltiformis in Etallon (1859) is a synonym of A. gracilis in Koby (1888). Measurements on the lectotype show that conceptions of Etallon and Koby are in agreement. The lectotype originates from St Claude according to Koby’s caption and from Valfin according to the old label and to the Etallon’s text but it can be thought that these localities are so close that, as it is assumed by Kuhn, Etallon and Koby worked on this same specimen.
Classification
Description
Massive cerioid colony. Strictly polygonal calices. Pachytheca with a median line (the wall is not really shared between two adjacent corallites as usually in Scleractinia; for this reason it is sometimes described as phaceloid). Marginarium and Taschenknospung present. Radial elements are smooth with irregular sharp granules, mostly free septa, occasionnaly joined, flexuous to straight. Septa made of small numerous simple trabecules in weakly inclined series. Lonsdaleoid septa present. Septal apparatus with a strong bilateral symmetry. A septum thicker than others at least in some species. Eccentric axial pit. Peripheral steeply inclined vesicular dissepiments. Cellular central dissepiments controversial. Striated epitheca not necessarily complete present around each corallite. No peritheca, no synapticula, no palus, no columella
Comparisons
Oyonnaxastraea has a thicker wall and an axially thickened major septum but could range in the variability of Amphiastrea. Acanthogyra shows strong granules on lateral faces of septa and a septal budding. Heterastraea has large teeth on inner-distal edge of septa. See also Connectastrea.
Remarks
12 Jurassic and 16 Cretaceous nominal species. Amphiastrea valoniensis from the Hettangian does not belong to Amphiastrea. See Eliasova 1975, Kolodziej 1995, 2003 for complementary illustrations.
Distribution
- Western Europe, Southern Europe, Central Europe, Eastern Europe, Central Asia, East Asia; Late Jurassic - Late Cretaceous
This page has been in preparation since 21-Aug-2009 17:01
This version was contributed by Bernard Lathuilière on 17-May-2014 10:51.
Page authors are: Bernard Lathuilière. 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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