Periseris
Ferry, 1870, p. 195
Type Species
Agaricia elegantula D'Orbigny, 1850, p. 293; Monotypy
Type Specimen: Lectotype; MNHN A26574; Verified; Dry Preserved
Type Locality: Bajocian (Middle Jurassic) from Langres (Haute Marne; France)
A revision of the type-species was published by Lathuilière, 1990. Since this publication, the lectotype was found again and it ranges in the variability described in 1990.
Classification
Description
Massive, often lamellar corallum. Epitheca often present thick and concentrically wrinkled. Intracalicinal increase producing isotropic thamnasterioid structures to meandroid structures in which ill-defined series are arranged concentrically. Radial elements are subcompact anastomosed sinuous pennular biseptal sheets. Distal edge with stout subequal regular teeth corresponding to trabecules organised in a fan system, lateral faces with continuous menianae. Pennular rims turned toward the distal direction. No palis. Hexameral symmetry not deciphered, bilateral symmetry marked by the torsion of septa and distribution of anastomoses. Endotheca made of vesicular dissepiments, columella styliform, synapticulae present, wall absent.
Comparisons
The pennular morphology is different from Thamnasteria. The columella is different from Protoseris
Remarks
Five nominal species were created. Various species initially attributed to Thamnasteria belong to Periseris (Lathuilière 1990). The relationships (synonymy ?) with the Triassic Thamnasteriamorpha is not well established.
Distribution
- Western Europe, Central Europe, North Africa, Central Asia, South Asia; Early Jurassic - Middle Jurassic
This page has been in preparation since 19-Aug-2009 16:47
This version was contributed by Bernard Lathuilière on 16-Apr-2010 10:21.
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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