Beauvais and Mori, 1988: 104
Latomeandra? eguchii Mori, 1963: 61, pl. 23, fig. 4, 5.; Monotypy Beauvais and Mori ,1988: 104
Type Specimen: Holotype; ; Not Traced; Unknown
Type Locality: Soma Province, Japan. Jurassic Somanakamura Group, Nakanosawa Fm., Koike limestone
Meandroid. Corallites in monolinear series; collins with a wall of a structure so far unknown in the Jurassic, made of vertical pillars and stereome. Calices well marked, deep. Along both sides of the wall, large, lonsdaleoid dissepiments form a common vesicular, peripheral zone. Peripheral dissepiments slope steeply toward the calicular centers to form tabuloid endothecal structure. Inner calicular part is incompletely surrounded by an inner stereomal wall developed as a deposit on the surface of dissepiments. Septa differentiated into at most two size orders, vertically continuous in the inner calicular parts, peripherally discontinuous, lonsdaleoid, and between the series connected by the intermediate of the wall pillar. One S1 septum per calice may be strongest from others. Increase by incomplete division inside the series.
Kei Mori (1963: 61, pl. 23, fig. 4, 5) described briefly colony structure and illustrated it with thin sections. Beauvais and Mori (1988:104, pl.1, fig.1-3; text fig.1) repeated illustrations of the transverse and longitudinal thin sections, generally, perpendicular to the calicular series, and completed the figures with longitudinal, slightly oblique section parallel to the series.
The genus is highly similar to Barremian-Aptian Rhipidomeandra Morycowa and Masse, 1998, family Trochoidomeandridae, in the structure of collins, with common vesicular zones developed of lonsdaleoid dissepiments on both sides of the middle stereomal wall, confluent septa in the collins and calices distributed in monolinear series (1998: p.735, fig. 9:1a,b, 2a,b, 3). It differs from Rhipidomeandra in wide dissepimental zones and septa differentiated into only two size orders; further finds will clarify their relations. Due to this closeness to Rhipidomeandra, the genus has been re-classified to the family Trochoidomeandridae. The original attribution of the genus to Amphiastraeidae cannot be maintained, because it has neither pachytheca, nor pocket budding; large dissepiments with lonsdaleoid septa were misinterpreted as new corallites increasing by pocket budding (Taschenknospung) typical of the amphiastreids.
Only one species is known.
Known only from the Late Jurassic of Japan
- South Asia; Late Jurassic
This page has been in preparation since 07-May-2009 07:22
This version was contributed by Ewa Roniewicz on 19-Nov-2010 18:57.
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