Scleractinian corals of suborders Pachythecaliina and Rhipidogyrina: discussion on similarities and description of species from Štramberk-type limestones, Polish Outer Carpathians
Abstract
Koralowce z podrzędu Pachythecaliina i Rhipidogyrina (Scleractinia): dyskusja nad podobieństwami oraz opis gatunków z wapieni typu sztramberskiego, Polskie Karpaty zewnętrzne
Similarities between scleractinian corals from extinct suborders Pachythecaliina Eliasova 1976 and Rhipidogyrina Roniewicz 1976 are discussed. Corals of the former suborder are considered by some authors as possible descendants of Palaeozoic Rugosa because of their unusual skeletal characters. Some rhipidogyrinans, especially the family Aulastraeoporidae, despite their different septal microstructure, share more common features with pachythecaliinans than with other scleractinians. The following skeletal features are discussed to show similarities between these two suborders: (1) wall microstructure and its relations to septa, (2) corallite bilateral symmetry, (3) marginarium, (4) lonsdaleoid and apophysal septa, and (5) internal septal margin. These similarities can be explained by convergence, although phylogenetic relationships of both suborders can not be excluded. This hypothesis needs to be verified by more studies, especially on early blastogeny of rhipidogyrinans and wall microstructure of pachythecaliinans. The systematic part gives descriptions of the discussed coral suborders occuring in the Śtramberk-type limestones, the Polish Outer Carpathians (Tithonian-?Berriasian, ?Valanginian). Similarly as in the Śtramberk Limestone (Moravia), pachythecaliinans are highly diversified (17 species, 12 genera, including Pachythecophyllia eliasovae n.gen., n.sp.). Rhipidogyrinans are represented by 4 species of 4 genera, including lOgilvinella morycowae n.sp.
Similarities between scleractinian corals from extinct suborders Pachythecaliina Eliasova 1976 and Rhipidogyrina Roniewicz 1976 are discussed. Corals of the former suborder are considered by some authors as possible descendants of Palaeozoic Rugosa because of their unusual skeletal characters. Some rhipidogyrinans, especially the family Aulastraeoporidae, despite their different septal microstructure, share more common features with pachythecaliinans than with other scleractinians. The following skeletal features are discussed to show similarities between these two suborders: (1) wall microstructure and its relations to septa, (2) corallite bilateral symmetry, (3) marginarium, (4) lonsdaleoid and apophysal septa, and (5) internal septal margin. These similarities can be explained by convergence, although phylogenetic relationships of both suborders can not be excluded. This hypothesis needs to be verified by more studies, especially on early blastogeny of rhipidogyrinans and wall microstructure of pachythecaliinans. The systematic part gives descriptions of the discussed coral suborders occuring in the Śtramberk-type limestones, the Polish Outer Carpathians (Tithonian-?Berriasian, ?Valanginian). Similarly as in the Śtramberk Limestone (Moravia), pachythecaliinans are highly diversified (17 species, 12 genera, including Pachythecophyllia eliasovae n.gen., n.sp.). Rhipidogyrinans are represented by 4 species of 4 genera, including lOgilvinella morycowae n.sp.