Coral-ID - Weißenegg-formation, Styrian basin, Eastern Alps (Langhian, Miocene)

[FranzBernhard]

Waiting for Christkind and(!)/or(??) Santa Claus gives me some time putting together this question:

 

The coral in question comes from the Styrian basin (Weißenegg-formation) and is Langhian/Miocene in age (ca. 15 Ma old). It comes from a very small road outcrop, mainly limestones, north of Heimschuh in the Sausal mountains, southern Styria, Austria. Beside massive, sturdy coral colonies like Montastrea, possibly Favites, etc., another colonial coral occurs in this outcrop, that disintegrates easily into individual sticks or pencils, aka corallites:

Outcrop situation, field of view ca. 80 cm. It looks really something strange and unusual.

 

These are individual corallites or they are in the stage of branching; the middle one is about 8 cm high.

 

Sometimes you can retrieve parts of colonies. Remarkable is the large diameter of the corallites, up to 2 cm.

 

With the help of some superglue, it was possible to make some polished slabs of these corals (the matrix is a rather soft marl). Note the highly varying diameter of the corallites and the budding. Especially interesting is the specimen to the lower left. Here, some big (about 2 cm diameter!) polygonal corallites are tightly growing together. But I think, its the same as the other ones.

 

A possible genus that comes to my mind is Acanthastrea. This idea is based on the shear size of the corallites. This genus is know from an outcrop a few km away and also from a similar formation of similar age about 100 km away (Mühlendorf, Burgenland, Austria), the species mentioned/described there is A. horrida. But my idea, that these could be also Acanthastrea could be totally wrong, of course...

 

Thanks for your help and Merry Christmas!
Franz Bernhard

[HansTheLoser]

Well it seems it is a phaceloid coral (that would also explain desintegration). All given names are plocoid genera. For the assignation of the family a closer look at septal microstructure is necessary.

[FranzBernhard]

Thanks, @HansTheLoser! Back to scratch!
Franz Bernhard