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The earliest growth stages of amphiporids and archaeocyaths - a comparison
Hladil, Jindřich
The initial growth stages of amphiporids and archaeocyaths are mutually similar to identical. They both consist of (1) rudimentary bottom disc (covered by small tubercles or septum-like bulges), (2) first chamber, (3) smooth first tube and (4) an interval with relatively rapid metamorphosis to complex adult morphologies. Probably no sponges can produce such an earliest skeletal formation that consists of the first chamber and tube, both resembling an external wall, because the typical sponge gemmules usually produce a number of cells that expand laterally very fast, forming a soft network, and it is a very different process. The great degree of similarity between the earliest growth stages of amphiporids and archaeocyaths suggests that there was a sharply separated group of "archaeocyathid-amphiporid" organisms (working name "Amphicyathida"), which was different from other corals, sponges or stromatoporoids.
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Report on research in the San Salvador Island, Bahamas
Bosák, Pavel ; Hladil, Jindřich ; Slavík, Ladislav ; Melka, Karel ; Venhodová, Daniela ; Chadima, Martin ; Hercman, H. ; Nowicki, T.
Contact of two cycles at shallow carbonate platform shows traces of karstification, formation of soils and important changes of geochemistry (U, Th, K, Fe) and magnetic susceptibility.
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Ekologické vazby ohledně endolitických producentů mikrovrteb a substrátů v barrandienských vápencích devonského stáří, Česká republika
Hladil, Jindřich
The microboring activity in barrandian seas was generally low. It was limited by relatively cold geostrophic currents in outer parts, and the seafloors in inner basin depressions were also adversely influenced by stagnant d18O-positive and heavy-metal-rich bottom waters. The really flourished microborers were only in two stratigraphical intervals, and both have shown /"redbeds-like/" deposits. The first developed close with major end-Tippecanoe regressions in Praha sequence, and the second occurred in the Daleje-Trebotov sequence. These /"redbeds-like/" periods correspond mineralogically, geochemically and paleobiologically to relatively hot humid climates (~ mesotrophic but well oxygenated waters). It differed from other long intervals characterized by marine Corg and silica burial (cherts)
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