Axosmiliidae

Geyer, 1955

Diagnosis

Radial elements are compact costosepta with a strong costal part, almost free. Costosepta bicuneiform, generally straight, sometimes curved according to the bilateral plan. Lateral faces display unequal granules, randomly arranged. Thick septa are smoother. Distal margin exhibits a weak ornamentation mainly characterised by the zigzag pattern which is visible in thinner septa. On transverse sections, the internal margin displays no denticulation. The microstructure is characterised by a zigzag mid-septal line which gives birth to a microarchitecture marked by zigzag shaped young septa and by randomly arranged granules in older septa. The original microarchitecture is progressively smoothed during growth by addition of laminar layers, firstly in the wall region and secondarily nearby the internal edge. In most genera, radial elements are very regularly arranged in cyles according to their length and their thickness (but see Columnaphyllia for an exception). "Epitheca" or external coating folded, constant in the younger stage, incomplete in the later stage. There, it appears to be made of dissepiments. Short, unequal, unornamented costae, corresponding to septa. The columella is essential, lamellar and continuous. The microarchitecture is similar to septa. It is surrounded by a small groove. The endotheca is made of few large vesiculous dissepiments distally convex in the outer part and of dissepiments (or tabulae ?) perhaps more distally concave nearby the columella. The wall is made up by the enlargement of septa, itself induced by the development of laminar layers of the stereome which are in continuity with thickened dissepiments. No pali; no synapticulae.

Contains

• Axiphyllum Quenstedt, 1880, p. 684
• Axosmilia Milne Edwards, 1848, p. 467
• ?Axotrochus Beauvais, 1986, p. 23
• Bathmosmilia Alloiteau, 1958, p. 73
• Blastosmilia Etallon, 1859, p. 53
• Geyeriopsis Krasnov, 1983, p. 64
• Placophyllia Orbigny, 1849, p. 8
• ?Plesiosmilia Milaschewitsch, 1876, p. 189

This page has been in preparation since 02-Oct-2009 17:15

This version was contributed by Ken Johnson on 02-Oct-2009 17:15.

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