Browsing by Author "Prevec, Rose"

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    Revision and biostratigraphic implications of Thore Halle’s Permian plant fossils from the Falkland (Malvinas) Islands
    (The Evolutionary Studies Institute, 2024-12) McLoughlin, Stephen; Prevec, Rose; Cariglino, Bárbara; Philippe, Marc
    The Permian fossil plant assemblages from the Lafonia Group on the Falkland (Malvinas) Islands collected by Thore Gustav Halle on the 1907–1909 Swedish Expedition to Patagonia and Tierra del Fuego are re-described and their systematic placement revised. Two species of sphenophytes based on foliage and one on axial remains are recognized. Eight morphotypes of Glossopteris are differentiated using more rigorously defined criteria than Halle’s original character sets. A single species each of cordaitaleans and conifers are recognized. The absence of ferns and lycophytes may indicate significant taphonomic filters on the composition of the plant assemblages. Re-assessment of the characters of the fossil woods and their nomenclatural and taxonomic problems suggests that only a single species is recognizable in the assemblage. Several of the wood and leaf species bear evidence of fungal degradation along with a broad array of arthropod herbivory and oviposition damage that add to the diversity of biotic interactions documented in the middle–high southern latitude Glossopterid Biome of the late Paleozoic. The ages of the various fossiliferous units on the Falkland (Malvinas) Islands remain equivocal, but similarities with chronostratigraphically constrained leaf assemblages from the Karoo Basin, South Africa, suggest that the Bay of Harbours Formation (uppermost unit of the Lafonia Group) is referable to the upper Guadalupian to lowermost Lopingian.
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    A structural re-interpretation and revision of the type material of the glossopterid ovuliferous fruitification Scutum from South Africa
    (Bernard Price Institute for Palaeontological Research, University of the Witwatersrand, 2011-12) Prevec, Rose
    The Early Permian glossopterid fructification Scutum, described by Edna Plumstead in the 1950s from the Vereeniging locality in the Karoo Basin of South Africa, was one of the first glossopterid seed-bearing organs to be found in organic attachment to Glossopteris leaves. Examination of the type material necessitated a revision of this plant fossil genus and a re-evaluation of described South African species. Key characteristics of the genus are the broad and prominent wing, and a low receptacle length to width ratio (<2:1). Specimens of South African Scutum are currently attributed to three species, from two localities, but display intergrading morphological features that can be reasonably accommodated within a single species, S. leslii. Three-dimensional interpretation and reconstruction of impression fossils of Scutum fructifications preserved in attachment to Glossopteris leaves confirms that the seed-bearing surface of the receptacle faces the adaxial surface of the subtending leaf. The nature of the seed scars on the receptacle and their relationship to the peripheral wing of the fructifications is clarified.