Abstract Detail



Paleobotany

Wilf, Peter [1], Zou, Xiaoyu [1], Donovan, MIchael P. [2], Kocsis, László [3], Briguglio, Antonino [4], Shaw, David [5], Lambiase, Joseph J. [6].

Paleobotanical Reconnaissance of Brunei.

The Malay Archipelago is one of the most biodiverse regions, but it suffers the highest extinction risks on the planet due to increasing anthropogenic pressures. Paleobotanical knowledge provides an essential tool for motivating conservation, along with reconstructions of biogeography and paleoenvironments through time. Although much of the Malesian bioregion is well studied palynologically, there have been almost no investigations of Cenozoic macrofossils in 100 years or more. We report the first paleobotanical survey of Brunei Darussalam, a nation on the north coast of Borneo that still preserves the majority of its extraordinarily diverse, old-growth tropical rainforests. We discovered abundant compression floras dominated by angiosperm leaves at two sites of probable Pliocene age: Berakas Beach (BB, 253 specimens), in the Liang Formation, and Jalan Lugu (JL; 205 specimens), in an undescribed stratigraphic unit. Both sites yielded rich palynofloral assemblages from the macrofossil-bearing beds, which although not age-specific, are consistent with a Pliocene or possibly late Miocene age. Each palynological assemblage is dominated by fern spores, with abundant fungal and freshwater algal (Botryococcus) remains, rare marine microplankton, and components derived from mangrove swamps, the bordering tropical rainforest, and distal uplands. The depositional environments were a lowland fern-dominated swamp (BB) and a mangrove swamp (JL). Significant palynotaxa at one or both sites include polypod ferns, Cyathea, and Selaginella; a mangrove component including Zonocostites ramonae, Avicennia, Laguncularia, and Nypa; a lowland rainforest contribution including Euphorbia, Solanaceae, Dipterocarpaceae, Malvaceae, and Sapotaceae; and an upland component including Podocarpus, Proteaceae, and Ilex. Compressed fossil leaves at both sites represent influx to the depocenters from the bordering forests. The leaf specimens mostly have similar elliptic, pinnate, and untoothed morphology typical of lowland tropical rainforests, and only a small percentage preserve informative venation details. Nevertheless, we can distinguish about 17 leaf and one fruit morphotype among the two sites. Dipterocarps, the dominant regional life form with many threatened species, are well represented, including (at BB) fruit-wing fragments similar to Shorea or Hopea as well as plicate leaves similar to Dipterocarpus. At JL, the most common leaf type has numerous, thin secondary veins and acuminate apices, closely resembling the dipterocarp Dryobalanops. Palmately veined leaves include likely Malvaceae (BB), Rhamnaceae (cf. Ziziphus, BB), and Melastomataceae (JL). This work demonstrates that rich opportunities exist for paleobotanical exploration in the Malay Archipelago to improve our understanding of regional floristic history and inform the conservation of living evolutionary heritage.


Related Links:
Faculty Web Page in Biology Department at UNC-Greensboro
Google Scholar Profile - John Z. Kiss
NASA web site describing recent spaceflight experiments
Interview with John Z. Kiss on NASA TV
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1 - Pennsylvania State University, Dept. of Geosciences, University Park, Pennsylvania, 16802, United States
2 - Cleveland Museum of Natural History, Department of Paleobotany and Paleoecology, Cleveland, OH, 44106, USA
3 - Universiti Brunei Darussalam, Geology Group, Faculty of Science, Gadong, BE, 1410, Brunei Darussalam
4 - Università degli Studi di Genova, Dipartimento di Scienze della Terra, dell'Ambiente e della Vita , Corso Europa 26, Genoa, I – 16132 , Italy
5 - Biostratigraphic Associates (UK) Ltd., 17 Woodland Avenue, Norton Green, Stoke-on-Trent, ST6 8NE, UK
6 - Lambiase Geoscience, Nokomis, FL, 34275, USA

Keywords:
Borneo
Neogene
Paleobotany
Palynology
Dipterocarpaceae
Pliocene
Malesia
Rainforests
Ferns
Mangroves.

Presentation Type: Oral Paper
Session: PAL4, Paleobotany II: Cenozoic Paleobotany
Location: Virtual/Virtual
Date: Tuesday, July 28th, 2020
Time: 2:00 PM
Number: PAL4007
Abstract ID:227
Candidate for Awards:None


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