In Silurian loboliths (Camarocrinus, bladder‐like root of Scyphocrinites) two morphogenetic types are recognized: an older and previously almost unknown ‘cirrus lobolith’, and the familiar cosmopolitan ‘plate lobolith’. Their functional interpretation as buoys, for the latter type so far mainly based on its unusual form and mode of occurrence, is supported by (1) approximation to the paradigm, (2) buoyancy calculations of the gas contents, and (3) physical‐technical considerations based on the optimation involved in the phylogenetic transition from cirrus to plate loboliths.
Die lange Zeit umstrittene Funktion der Lobolithen (hohle, kugelförmige Wurzelregion von Scyphocrinites) wird an zwei verschiedenen, aber phylogenetisch nahe verwandten Bautypen, dem bisher praktisch unbekannten, stratigraphisch älteren ‘Cirren‐Lobolithen’ und dem schon mehrfach bearbeiteten ‘Platten‐Lobolithen’, untersucht. Beide hatten mit Sicherheit Ballon‐Funktion; denn(l) entspricht ihr Bau dem Paradigma dieser Funktion, (2) besaßen beide Lobolithen auf Grund ihrer Gasfüllung eine mehr als ausreichende Tragkraft, (3) entspricht der Übergang von Cirren‐ zu Platten‐Lobolithen einer weiteren Optimierung der Ballon‐Funktion.
Four outcrops (three of which were new) in the Northern Rhenish Schiefergebirge delivered several ophiuroids from the high Famennien. Following forms are described: Protaster ? ubaghsi n. sp. and a juvenile protasteroid, gen. et spec. indet., 2 new species of Furcaster to be treated taxonomically only after revision of this genus, many specimens of Ophiaulax decheni showing plates of the primary rosette and other hitherto undescribed structures, Stephanoura belgica with many juvenile specimens, and Onychaster ? velbertensis n. sp. as the first representative of the Onychasteridae in the Rhenish Schiefergebirge.K urzfass ung: Vier Ophiuren-Vorkommen (drei neue und ein bereits bekanntes) des hohen Oberdevons im niirdlichen Rheinischen Schiefergebirge werden bearbeitet. Daraus werden die folgenden Formen beschrieben: 2 Protasteridae, Pro taster ?ubaghsi n. sp. und ein juveniles Exemplar, gen. et spec. indet.; 2 neue (unbenannte) Arten der revisionsbediirftigen GattungFurcaster; Ophiaulax decheni mit den Platten der Primarrosette und weiteren neuen Strukturen; Stephanoura belgica mit zahlreichen juvenilen Exemplaren; Onychaster ?velbertensis n. sp. als erster Vertreter der Onychasteridae im Rheinischen Schiefergebirge.
Three sections (Atrous 3, Atrous 7 and Bou Tchrafine N2) in the “Scyphocrinites Limestones” of Tafilalt (southeastern Morocco) have been investigated for conodont and crinoid stratigraphy.\ud
Conodonts allow to discriminate four biozones (Ozarkodina eosteinhornensis s.l., Lower Oulodus elegans detortus, Upper O. elegans detortus, and Icriodus hesperius) of Pridoli and the lowermost Lochkovian. Cirrus loboliths occur only in the Pridoli, whereas plate loboliths are present in the\ud
uppermost Silurian and the basal Devonian; the two types overlap in the uppermost Silurian. As for calices, Scyphocrinites and Carolicrinus occur in the whole Pridoli; Camarocrinus and Marhoumacrinus are present across the Silurian–Devonian boundary and in basal Devonian beds
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