Silurian reef-dwelling pentamerid brachiopods, Wisconsin and Illinois, USAWatkins, Rodney
doi: 10.1007/bf02987819pmid: N/A
Eight species of pentamerid brachiopods, assigned toApopentamerus, Capelliniella, Kirkidium, Lissocoelina, Rhipidium, Supertrilobus andStenopentamerus, occur in stromatoporoid-coral reefs of the Silurian (Wenlockian) Racine Formation, Wisconsin and Illinois, USA. One new taxon,Rhipidium kuglitschi n.sp., is described. In contrast to level-bottom communities, where single pentamerid species occur in great numbers over large areas, pentamerids were generally rare members of the Racine reef fauna, and most species have localized distributions. An increase in diversity from one pentamerid species in the north to six species in the south correlates with a southward increase in reef size. Four morphologic groups of pentamerid species differed in the shape of the mantle cavity, which suggests different dynamics of suspension-feeding. Where two or more species are present in single reefs, co-occurrence of these groups represents a partitioning of the pentamerid niche. The relatively high diversity, local distributions, and morphologic distinctions among the Racine pentamerid fauna represent an evolutionary radiation and functional specialization of pentamerids in Wenlock reefs.
New finds of vertebrates in the Middle Devonian Brandenberg Group (Sauerland, Northwest Germany)Otto, Markus
doi: 10.1007/bf02987821pmid: N/A
The arthrodires of the Eifelian Brandenberg Group of Hagen-Ambrock and Lasbeck (Northwest Germany) are described. A new tuberculated holonematid arthrodire (Holonema bruehni n. sp.) is represented by plates of the trunk shield and some plates of the head region. The tuberculation is here regarded as the plesiomorphic character of the Holonematidae compared to an ornamentation of ridges in advanced genera. This agrees with the stratigraphical occurrence of the new form. Additionally, several other plates belonging to at least three different taxa of coccosteid arthrodires have been found. Despite the absence of complete skeletons, the placoderm fauna is more diverse than the fauna of the classical Scottish Eifelian localities.
New finds ofOmphalosaurus and a review of Triassic ichthyosaur paleobiogeographySander, P. Martin; Faber, Christiane
doi: 10.1007/bf02987823pmid: N/A
Triassic ichthyosaurs are very widespread and diverse but most taxa are poorly known. New discoveries, such as described in this paper, underscore the first statement but only slowy invalidate the second.The first associated skeleton of the unusual durophagous ichthyosaurOmphalosaurus (O. wolfi) is reported from the Middle Triassic (earliest Ladinian) of the northern Alps. The vertebrae are of the ichthyosaurian type, firmly establishing the ichthyosaurian affinities of the genus.A round bone from the Muschelkalk of Franconia, Germany, is identified and described as a left humerus ofOmphalosaurus sp. These finds greatly extend the paleogeographic and temporal range ofOmphalosaurus which previously was only known from the western cratonic margin of North America and from Spitsbergen. The new records ofOmphalosaurus allow a revised differential diagnosis of the genus and a revision of its species. Valid species ofOmphalosaurus areO. nettarhynchus, O. nevadanus, andO. wolfi.In conjunction with such new insights into Triassic ichthyosaur distribution, it is necessary to address the validity of the poorly known genera such as the Middle TriassicPessosaurus. This taxon must be considered invalid because it lacks diagnostic characters.In assessing progress in research on Triassic ichthyosaurs and their paleobiogeography, it becomes apparent that supra-specific diversity appears largely known, at least for the pre-Norian record of North America, Europe, and East Asia.
Anatomy of the prosauropod dinosaurBlikanasaurus cromptoni (Upper Triassic, South Africa), with notes on the other tetrapods from the lower Elliot FormationGalton, Peter M.; van Heerden, Jacques
doi: 10.1007/bf02987824pmid: N/A
The holotype of the prosauropod dinosaurBlikanasaurus cromptoniGalton & van Heerden 1985, a partial hindlimb, is described from the lower Elliot Formation (Red Beds; Carnian, Upper Triassic) of the Eastern Cape, South Africa.Blikanosaurus, along with the sympatricEuskelosaurus andMelanorosaurus, probably represent the oldest record of the Prosauropoda (certainly so for articulated remains). The prosauropod family Blikanasauridae is characterized by a hind-limb that is extremely stocky, especially the metatarsus.Blikanasaurus was an early heavily-built, quadrupedal saurischian, but it was probably not the ancestor for the Sauropoda. The other tetrapods of the lower Elliot Formation are reviewed with particular emphasis on the carnivorous dinosaurAliwalia rex.
Small theropod teeth from the Upper Jurassic coal mine of Guimarota (Portugal)Zinke, Jens
doi: 10.1007/bf02987825pmid: N/A
Isolated teeth of small theropod dinosaurs from the Upper Jurassic lignite coal mine of Guimarota (near Leiria, Portugal) are described and illustrated. The well known Upper Jurassic theropods from Europe,Archaeopteryx andCompsognathus, are the most common taxa in the Guimarota assemblage. One morphotype is closely related to an allosaurid theropod. Six further morphotypes of theropod teeth are also described, which are closely related to Cretaceous theropods such as dromaeosaurids, troodontids, tyrannosaurids,Richardoestesia andParonychodon. A Late Jurassic origin of these groups of theropods, which is very often postulated, is discussed.