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Isastrea

Milne Edwards and Haime, 1851: p. 102

Isastrea is a junior synonym of Confusastrea. Nevertheless, in order to preserve stability (ICZN art. 23.9.1) Lathuilière, Charbonnier and Pacaud (2017) promoted usage of this widely known genus over priority.

Type Species

Astrea helianthoïdes Goldfuss 1826 p. 65, pl.22 fig. 4; Subsequent Designation Quenstedt 1857, p. 375

Type Specimen: Lectotype; IPB 218; Verified; Dry Preserved

Type Locality: The lectotype comes from Upper Jurassic , Heidenheim (Germany). Initial syntypes were also signalled from Giengen

The type material is a lectotype by inference of holotype (art 74b) designated by Pelletier (1950). It is a mediocre specimen in which a thin transverse section was made.

Classification

Synonyms

Description

Massive cerioid colony with polygonal corallites. Intracalicular increase. No holotheca. Radial elements are compact, usually free but occasionally anastomosed in the axial zone, rather attenuated, straight, bent or curved, rarely sinuous, unequal in length and thickness. Costal part extremely short if present. Distal and inner edge with regular rhomboidal teeth, lateral faces with opposite subvertical carinae. Montlivaltid microstructure. No palis. Radial symmetry usually disturbed by a bilateral symmetry marked by the torsion of septa in transverse section . Endotheca made of numerous small vesiculose dissepiments sloping down from the wall to the axial zone. Columella absent but trabecular tissues can take place in depth of the axial zone, synapticulae rarely present in the wall zone. The wall is often in zigzag pattern, not always complete, composite in nature including septal elements, dissepimental elements and more rarely synapitules.

Remarks

127 nominal species were cited for Jurassic and 41 for Cretaceous (Loser 2000). There are also old citations of nominal species up to the Miocene. A precise description of well preserved specimens is available in Roniewicz 1982 (especially useful for microstructure and structure of the wall). See also Lathuilière (1988) for a study of intraspecific variability.

This page has been in preparation since 19-Aug-2009 14:48

This version was contributed by Bernard Lathuilière on 21-Jul-2017 14:55.

Page authors are: Bernard Lathuilière Ewa Roniewicz. Please contact the editor if you would like to contribute to the diagnosis of this taxon.

The editor is: Bernard Lathuilière


Lectotype of the type species of Isastrea
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Isastrea helianthoides type species of the genus
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Lectotype of the type species of Isastrea
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Lectotype of the type species of Isastrea
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