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Stellate patterns, called astrorhizae, occurring in some Paleozoic stromatoporoids are by most authors regarded as integral elements of these enigmatic fossils. The finding of stellate structures on epithecae of rugose corals from the Lower Carboniferous of Central Laos seems to support, however, the idea that astrorhizae in Paleozoic stromatoporoids may represent traces of foreign organisms.
The rugose coral genus Smithicyathus is diagnosed in this paper as massive to phaceloid phillipsastreid, with common horseshoe dissepiments and major septa that are very short in the tabularium. Revised taxonomy of this genus is based on analysis of over 20 numerical characters measured in sections and/or extracted from the literature data. Species are distinguished either by morphometric non−overlap in at least one, key feature or by geographic–stratigraphic isolation. The earliest possible representatives of the genus are known from the Eifelian of Angara (S.? emendatus and S.? russakovi). In the Upper Frasnian Smithicyathus is represented by seven species; in western Euramerica occur S. cinctus and S. mcleani sp. nov.; south−eastern Euramerican shelf area is with S. lacunosus, S. cf. lacunosus, S. smithi, S. cf. smithi, and S. lubliniensis; one probable species is recorded in Angara: S.? belkovskiense. The genus did not survive the Frasnian– Famennian crisis. Smithicyathus lived in tropical and sub−tropical shallow−marine carbonate environments, with the possible exception of the northern mid−latitudes species from Siberia. In the Holy Cross Mountains, S. lacunosus and S. smithi show a preference for restricted−marine facies. They may make up over 90% of all rugosan colonies collected in such locations, whereas in the more open−marine settings they are rare both in numbers and in proportion to other rugosan species.
An uppermost Famennian (Strunian) coral assemblage has been recovered in the middle part of the Yılanlı Formation of the Istanbul Zone (Zonguldak and Bartın areas, NW Turkey). In the Bartın area, the studied fossiliferous interval corresponds to a c. 30 m-thick unit of bioclastic to peloidal wackestone to packstone grading to grainstone and including two stromatoporoid biostromes. In the Zonguldak area, 60 km westward, the bioclastic facies is dominant. The rugose corals are mainly solitary taxa belonging to the genera Campophyllum, Bounophyllum, Amplexocarinia, and ?Metriophyllum, and only one colonial genus occurs: Pseudoendophyllum. This fauna is similar to that documented in Europe. The campophyllids and dibunophyllids are the main component of the uppermost Famennian assemblages in S Belgium, N France, W Germany, NW and S Poland. The endophyllids occur in S Poland, Novaya Zemlya, and in the Ural Mountains. The Istanbul Zone is supposed to be situated in the central part of the Palaeotethys Ocean, along the southern margin of Laurussia during the uppermost Devonian and Carboniferous. The rugose corals indicate some relationship with the eastern part of Laurussia, or that both areas were under a common marine influence at this time. The global Hangenberg event was not recognized in the Turkish localities, except for the disappearance of the corals, occurring less than 19 m below the Devonian–Carboniferous boundary based on the foraminifers. There is no major facies change through the boundary and the first Carboniferous corals (small Uralinia and Caninophyllum) appear 6 m above the D–C boundary. The new species Caninophyllum charli sp. nov. is described from the upper part of the lower Tournaisian.
This study focuses on the life strategies of small, dissepimented rugose coral Catactotoechus instabilis (representative of Cyathaxonia fauna) from the Emsian argillaceous deposits of mud mounds of Hamar Laghdad (Anti−Atlas, Morocco). Numerous constrictions and rejuvenescence phenomena as well as frequent deflections of growth directions among the studied specimens suggest unfavourable bottom conditions resulted from sliding down of the soft sediment on the mound slopes. Dissepimental structures observed on well−preserved calices and thin sections played an important role in the life of the coral, supporting their successful recovery after temporary burial within unstable soft sediment. The development of lonsdaleoid dissepiments, apart from being biologically controlled, was also strongly influenced by environmental factors. Such modifications in lonsdaleoid dissepiments growth were observed in phases of constrictions, rejuvenescence and deflections of growth, when their development was significantly increased in comparison to phases of their stable growth. Dissepiment morphology suggests that the process of formation of lonsdaleoid dissepiments in Catactotoechus instabilis is consistent with the hydraulic model.
Two species of Lower Devonian rugose corals are described from the Cantabrian Mountains of Spain: Cantabriastraea cantabrica gen. et sp. nov. and Tabulophyllum bonarense sp. nov. The development of rootor buffer−like attachment structures (“rhizoid processes”) in T. bonarense indicates adaption to the soft substrate and supports corallite stabilisation. Because of their strongly everted calices and a corresponding arrangement of trabeculae, the colonies of the genus Cantabriastraea are assigned tentatively to the Paradisphyllinae, constituting the first record of the subfamily in Western Europe. Some specimens give information on colony−formation of this taxon, which is induced by strong lateral budding (nonparricidal increase) of a remarkable large and long−lasting protocorallite.
We present taxonomic revision of rugose corals and brachiopods from several Frasnian–Fammenian (F–F) boundary sections in central Hunan Province, China. Diversity of shallow−water rugose corals gradually increased during the Frasnian, but ended with sudden extinction near the end of Frasnian. Ostracods were abundant during the Frasnian; their extinction coincided with anoxic deposition of the end−Frasnian black shale deposits. The early Famennian ostracod fauna is of low diversity. The brachiopod fauna of the late Frasnian (Palmatolepis rhenana and Pa. linguiformis zones) is dominated by atrypids, small−sized cyrtospiriferids, and the rhynchonellid Hunanotoechia. All atrypids disappeared before the F–F boundary with highest rates of extinction below the boundary (probably low in the Pa. linguiformis Zone). The Frasnian cyrtospiriferid fauna is also of low diversity and dominated by small taxa. All but one of the cyrtospiriferid taxa crossed the F–F boundary. The early Famennian post−extinction recovery brachiopod fauna was the result of rapid radiation of new forms shortly after the terminal Frasnian event. The early Famennian fauna is characterized by diverse cyrtospiriferids, abundant Yunnanellina and productoids. Above the early recovery fauna another fauna was recovered, with brachiopods Hunanospirifer and Yunnanella and is correlated with the late or latest Pa. crepida Zone. Sinalosia rugosa gen. et sp. nov. (Productida) is erected.
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