Natural history of a plant trait: branch-system abscission in Paleozoic conifers and its environmental, autecological, and ecosystem implications in a fire-prone world

Paleobiology ◽  
10.1666/12030 ◽  
2013 ◽  
Vol 39 (2) ◽  
pp. 235-252 ◽  
Author(s):  
Cindy V. Looy
Keyword(s):  
Fire Regime ◽  
Climatic Conditions ◽  
Early Permian ◽  
North Central ◽  
Seasonally Dry ◽  
Plant Trait ◽  
Branch System ◽  
Central Texas ◽  
History Of ◽  
Biotic Disturbance

Within conifers, active abscission of complete penultimate branch systems is not common and has been described mainly from juveniles. Here I present evidence for the abscission of penultimate branch systems within early so-called walchian conifers—trees with a plagiotropic branching pattern. The specimens studied originate from a middle Early Permian gymnosperm-dominated flora within the middle Clear Fork Group of north-central Texas. Complete branch systems of three walchian conifer morphotypes are preserved; all have pronounced swellings and smooth separation faces at their bases. The source plants grew in a streamside habitat under seasonally dry climatic conditions. The evolution of active branch abscission appears to correspond to an increase in the size of conifers, and this combination potentially contributed to the restructuring of conifer-rich late Paleozoic landscapes. Moreover, trees shedding branch systems and producing abundant litter have the potential to affect the fire regime, which is a factor of evolutionary importance because wildfires must have been a source of frequent biotic disturbance throughout the hyperoxic Early Permian.

Aspects of the postcranial skeleton of the Lower Permian lungfish, Gnathorhiza

1989 ◽  
Vol 63 (6) ◽  
pp. 919-930 ◽  
Author(s):  
Walter W. Dalquest ◽  
M. John Kocurko ◽  
John V. Grimes
Keyword(s):  
Axial Skeleton ◽  
Lower Permian ◽  
Fish Scales ◽  
Early Permian ◽  
Postcranial Skeleton ◽  
Caudal Fin ◽  
North Central ◽  
New Information ◽  
Central Texas ◽  
Median Fins

A newly discovered locality of aestivation burrow casts containing the lungfish, Gnathorhiza serrata, is reported from the early Permian Arroyo Formation of Wilbarger County, north-central Texas. Remains preserved in the burrow casts provide sections of mummified Gnathorhiza and new information about the postcranial skeleton of this fish. Scales of Gnathorhiza resemble those of the modern lungfishes such as Lepidosiren in their microanatomy. No traces of paddle-like pectoral or pelvic fins were found and paired fins of Gnathorhiza may have resembled those of Lepidosiren. The axial skeleton and median fins of Gnathorhiza seem to resemble those of Lepidosiren except that the tail area and caudal fin of Gnathorhiza were stout and strong rather than slender and tapering. Gnathorhiza, which aestivated tail-down in its burrow, may have required a stout tail for support.

Late Early Permian continental ichnofauna from Lake Kemp, north-central Texas, USA

2011 ◽  
Vol 308 (3-4) ◽  
pp. 395-404 ◽  
Author(s):  
Spencer G. Lucas ◽  
Sebastian Voigt ◽  
Allan J Lerner ◽  
W. John Nelson
Keyword(s):  
Early Permian ◽  
North Central ◽  
North Central Texas ◽  
Central Texas

scholarly journals Fusulinids from the Howe Limestone Member (Red Eagle Limestone, Council Grove Group) in Northeastern Kansas and Their Significance to the North American Carboniferous (Pennsylvanian)-Permian Boundary

2010 ◽  
pp. 1-13
Author(s):  
Gregory P. Wahlman ◽  
Ronald R. West
Keyword(s):  
New Mexico ◽  
North American ◽  
Early Permian ◽  
North Central ◽  
The North ◽  
West Texas ◽  
North Central Texas ◽  
Central Texas ◽  
First Time

Fusulinids from the Howe Limestone Member (upper part of the Red Eagle Limestone, lower part of the Council Grove Group) are described here for the first time. The Howe fauna is particularly significant because it represents the earliest fusulinids known to occur above the new conodont-based Carboniferous (Pennsylvanian)-Permian boundary at the Glenrock Limestone Member-Bennett Shale Member contact (Red Eagle Limestone) in northeastern Kansas. The Howe fusulinid assemblage is composed entirely of species of the genus Leptotriticites. The species L. hughesensis and L. glenensis were originally described from just beneath the new systemic boundary horizon in the Hughes Creek Shale Member and Glenrock Limestone Member, respectively. L. wetherensis is a species from the Stockwether Limestone Member of north-central Texas, which is thought to directly overlie the new systemic boundary in that region. L. gracilitatus is a species reported from below and above the boundary in west Texas and New Mexico. Therefore, the Howe Limestone Member fusulinid fauna is quite transitional in character. The first typical and diagnostic early Permian (Wolfcampian Series) fusulinids in the midcontinent section appear in steps through the stratigraphically higher Neva Limestone Member of the Grenola Limestone (Paraschwagerina kansasensis), and the Cottonwood and Morrill Limestone Members of the overlying Beattie Limestone (Schwagerina jewetti, S. vervillei). This offset of conodont and fusulinid faunal changes should be taken into account in regional and interregional biostratigraphic correlations of the new systemic boundary.

Plant-Insect Interactions from Early Permian (Kungurian) Colwell Creek Pond, North-Central Texas: The Early Spread of Herbivory in Riparian Environments

2014 ◽  
Vol 175 (8) ◽  
pp. 855-890 ◽  
Author(s):  
Sandra R. Schachat ◽  
Conrad C. Labandeira ◽  
Jessie Gordon ◽  
Dan Chaney ◽  
Stephanie Levi ◽  
...  
Keyword(s):  
Early Permian ◽  
North Central ◽  
Plant Insect Interactions ◽  
North Central Texas ◽  
Central Texas ◽  
Insect Interactions

Palaeoecology of the Early Permian strata at Heimefrontfjella, Dronning Maud Land, Antarctica

1994 ◽  
Vol 6 (4) ◽  
pp. 507-515 ◽  
Author(s):  
Dorothy Guy-Ohlson ◽  
Sofie Lindström
Keyword(s):  
Green Alga ◽  
Climatic Conditions ◽  
Late Paleozoic ◽  
Early Permian ◽  
Organic Residues ◽  
Geological Investigation ◽  
Stage Of Development ◽  
History Of ◽  
Dronning Maud Land

Palaeopalynological studies form an integral part of the geological investigation of the Late Paleozoic sedimentary history of Dronning Maud Land. During the examination of organic residues prepared from different localities at Heimefrontfjella, the freshwater green alga Botryococcus was found. Exceptionally well-preserved colonies of Botryococcus were recorded in several samples at two sections of Early Permian age, Lidkvarvet and Locality A. These colonies vary in form and stage of development. By analogy with observations on recent material the following palaeoecological conclusions are drawn: 1) varying environmental and climatic conditions over a length of time existed at Lidkvarvet, and 2) very short ephemeral aquatic conditions existed intermittently at Locality A.

scholarly journals Long-term impacts of mid-Holocene drier climatic conditions on Bolivian tropical dry forests

2019 ◽  
Vol 93 ◽  
pp. 204-224 ◽  
Author(s):  
Heather J. Plumpton ◽  
Francis E. Mayle ◽  
Bronwen S. Whitney
Keyword(s):  
Climate Models ◽  
Fire Regime ◽  
Tropical Dry Forest ◽  
Climatic Conditions ◽  
Dry Forest ◽  
Tropical Dry Forests ◽  
Dry Forests ◽  
Seasonally Dry ◽  
Threat Status

AbstractThe Bolivian Chiquitano dry forest is the largest block of intact seasonally dry tropical forest in South America and is a priority ecoregion for conservation due to its high threat status. However, the long-term impacts of drier climatic conditions on tropical dry forests are not well understood, despite climate models predicting increased droughts over Bolivia in the coming century. In this paper, we assess the impacts of drier climatic conditions during the mid-Holocene on the Bolivian Chiquitano tropical dry forest using fossilised pollen, phytoliths, macro-charcoal, and geochemical proxies from a sediment core from a large lake (Laguna Mandioré) on the Bolivia–Brazil border. Our results show that drier climatic conditions during the mid-Holocene caused a local-scale, ecotonal expansion of upland savannah at the expense of dry forest. Interaction between drier climatic conditions and fire regime likely exerted a stronger control over the position of the dry forest–savannah ecotone than edaphic factors. However, the majority of the dry forest within the lake catchment maintained a closed canopy throughout the drier conditions of the mid-Holocene, despite floristic turnover towards more drought-tolerant taxa. These findings imply overall resilience of the Chiquitano dry forest biome to future drought, albeit with floristic changes and upland savannah encroachment at ecotones.

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