Abstract
| Originalsprog | Engelsk |
|---|---|
| Tidsskrift | Bulletin of Geosciences |
| Vol/bind | 82 |
| Udgave nummer | 4 |
| Sider (fra-til) | 365-382 |
| Antal sider | 18 |
| ISSN | 1214-1119 |
| Status | Udgivet - 2007 |
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I: Bulletin of Geosciences, Bind 82, Nr. 4, 2007, s. 365-382.
Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › peer review
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TY - JOUR
T1 - Partial reconstruction and palaeoecology of Sphenophyllum costae (Middle Pennsylvanian, Nova Scotia, Canada)
AU - Bashforth, Arden Roy
AU - Zodrow, Erwin L
PY - 2007
Y1 - 2007
N2 - Recovery of a large, articulate portion of Sphenophyllum costae Sterzel from lower Cantabrian strata of the SydneyCoalfield, Nova Scotia, Canada, demonstrates that it is the largest sphenophyll yet known to inhabit clastic substrates ofEuramerica. The specimen shows four orders of branching, with each axis characterized by whorls of leaves having distinct morphologies. Foliage clearly displays a tendency to become less divided on axes of ascending order. Furthermore, each branch order can be distinguished based on its internodal lengths and widths, which indicates that the species has a marked hierarchy of ramification similar to that found in the calamitalean sphenopsids. Axes of all orders apparently show epidogenetic followed by apoxogenetic growth patterns, which contributes to the high degree of heterophylly in the taxon. Comparison of axes and foliage of S. costae with other members of the genus reveals that sphenophylls from clastic substrates followed a fundamental ontogenetic pattern of growth and architecture, although subtle variations existed between taxa. Climber hooks are documented for the first time in the species, and the presence of these modified leaves supports the interpretation that S. costae formed dense, multi-branched thickets up to 2 m high comprising mutually supportive axes that rested upon, clung to, or entwined with adjacent axes. Palaeoecological and taphonomic evidence suggests that the plant formed as ground cover beneath arborescent medullosalean pteridosperms, and probably occupied well-drained (but moist) clastic habitats such as elevated channel margins or topographically raised hummocks on floodplains.
AB - Recovery of a large, articulate portion of Sphenophyllum costae Sterzel from lower Cantabrian strata of the SydneyCoalfield, Nova Scotia, Canada, demonstrates that it is the largest sphenophyll yet known to inhabit clastic substrates ofEuramerica. The specimen shows four orders of branching, with each axis characterized by whorls of leaves having distinct morphologies. Foliage clearly displays a tendency to become less divided on axes of ascending order. Furthermore, each branch order can be distinguished based on its internodal lengths and widths, which indicates that the species has a marked hierarchy of ramification similar to that found in the calamitalean sphenopsids. Axes of all orders apparently show epidogenetic followed by apoxogenetic growth patterns, which contributes to the high degree of heterophylly in the taxon. Comparison of axes and foliage of S. costae with other members of the genus reveals that sphenophylls from clastic substrates followed a fundamental ontogenetic pattern of growth and architecture, although subtle variations existed between taxa. Climber hooks are documented for the first time in the species, and the presence of these modified leaves supports the interpretation that S. costae formed dense, multi-branched thickets up to 2 m high comprising mutually supportive axes that rested upon, clung to, or entwined with adjacent axes. Palaeoecological and taphonomic evidence suggests that the plant formed as ground cover beneath arborescent medullosalean pteridosperms, and probably occupied well-drained (but moist) clastic habitats such as elevated channel margins or topographically raised hummocks on floodplains.
M3 - Journal article
SN - 1214-1119
VL - 82
SP - 365
EP - 382
JO - Bulletin of Geosciences
JF - Bulletin of Geosciences
IS - 4
ER -