Gymnosperms from the Lower Cretaceous Crato Formation (Brazil). I. Araucariaceae and <i>Lindleycladus</i> (incertae sedis)
Fossil conifers from the Early Cretaceous, most likely late Aptian, Crato Formation were studied. The excellent preservation of several of those fossils allowed detailed investigations of the leaf epidermis by light microscope (LM) and by scanning electron microscope (SEM). Members of two conifer ta...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Pensoft Publishers
2004-01-01
|
| Series: | Fossil Record |
| Online Access: | http://www.foss-rec.net/7/155/2004/fr-7-155-2004.pdf |
| Summary: | Fossil conifers from the Early Cretaceous, most likely late Aptian, Crato Formation were studied. The excellent preservation of several of those fossils allowed detailed investigations of the leaf epidermis by light microscope (LM) and by scanning electron microscope (SEM). Members of two conifer taxa were recognized: The Araucariaceae are represented by a female cone of cf. <i>Araucaria</i> spec. A juvenile cone (<i>Araucariostrobus spec.</i>) and sterile foliage shoots of <i>Brachyphyllum obesum might</i> be attributed to the Araucariaceae as well. The morpho-genus <i>Lindleycladus</i> (incertae sedis) is represented by foliage shoots. The occurrence of <i>Lindleycladus</i> is the first record of this extinct morpho-genus in the Southern Hemisphere. Anatomical features of these conifers are interpreted as adaptations to a warm seasonally dry climate. Taphonomic problems concerning these conifer remains are discussed.
<br><br>
Fossile Koniferen aus der unterkretazischen, höchstwahrscheinlich oberaptischen Crato Formation wurden untersucht. Die ausgezeichnete Erhaltung einiger Exemplare gestattete die Analyse von Blattepidermen mittels Licht- und Rasterelektronen-mikroskop. Vertreter zweier Koniferentaxa wurden nachgewiesen: Araucariaceae kommen mit einem weiblichen Zapfen von cf. <i>Araucaria spec</i>. vor. Ein juveniler Zapfen (<i>Araucariostrobus spec</i>.) und sterile Zweige mit der Beblätterung der Morpho-Species <i>Brachyphyllum obesum</i> werden unter Vorbehalt ebenfalls zu den Araucariaceae gestellt. Vegetative Organe der Morpho-Gattung <i>Lindleycladus</i> (incertae sedis) sind ebenfalls erhalten. Das Vorkommen von <i>Lindleycladus</i> ist ein erster Nachweis dieser fossilen Morpho-Gattung in der Südhemisphäre. Anatomische Merkmale dieser Koniferen werden als Anpassungen an ein warmes, saisonal trockenes Klima gedeutet. Im Zusammenhang mit den Koniferenresten werden taphonomische Probleme diskutiert.
<br><br>
doi:<a href="http://dx.doi.org/10.1002/mmng.20040070109" target="_blank">10.1002/mmng.20040070109</a> |
|---|---|
| ISSN: | 2193-0066 2193-0074 |