Plesiostylina
Alloiteau, 1958, p.18
Plesiostylina Alloiteau, 1958, p.18 is a junior synonym (available and invalid), see Stylina Lamarck, 1816.
Type Species
Plesiostylina hourcqi Alloiteau, 1958, p. 19, pl. X fig. 6; Monotypy
Type Specimen: Holotype; MNHN M05152; Verified; Dry Preserved
Type Locality: Lower Bathonian (Middle Jurassic) from Ampandrabé, Madagascar
The type species was figured only in Alloiteau, 1958
Classification
Description
(From the holotype). Massive plocoid corallum with circular to subcircular calices. Costae confluent to subconfluent, moderately developed. Extracalicular increase. Radial elements compact, free, straight, unequal in length and thickness. Inner edge auriculate, lateral faces apparently smooth (but the section is not good enough). Microstructure unknown. Radial octameral symmetry, no bilateral symmetry. Endotheca not observed, columella styliform and strong, synapticulae absent, wall parathecal to paraseptothecal.
Remarks
Two nominal species. The type-species is known by only one specimen. P. etalloni was placed provisionally in this genus (Beauvais, 1964). Alloiteau distinguished Plesiostylina from Stylina on the basis of its parathecal thin wall regularly in zigzag, its endotheca composed of a small number of subhorizontal dissepiments, its subcylindrical strong columella and the low number of radial elements. We don’t consider these characters valid and distinctive.
Distribution
- Western Europe, Subsaharan Africa; Middle Jurassic - Late Jurassic
This page has been in preparation since 21-Aug-2009 13:53
This version was contributed by Shaahin Zaman on 19-Sep-2011 15:47.
Page authors are: Shaahin Zaman. 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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