Middle Pleistocene deposits at La Côte, Val-de-Lans, Isère department, France: plant macrofossil, palynological and fossil insect investigations

2000 ◽  
Vol 159 (1-2) ◽  
pp. 53-83 ◽  
Author(s):  
M.H Field ◽  
J.-L de Beaulieu ◽  
J Guiot ◽  
P Ponel
2013 ◽  
Vol 53 (2) ◽  
pp. 181-189
Author(s):  
Michael H. Field

ABSTRACT A plant macrofossil assemblage extracted from Middle Pleistocene fluvial organic sediments collected from Belhus Park, Aveley, Essex, UK contained a number of tuberculate (verrucose) achenes attributed to the genus Ranunculus, one of which had two short spines preserved on its surface. The identification of these achenes is discussed here. This is worthy of note because Ranunculus tuberculate or spinose fossil achenes can be difficult to determine to species as they can have similar features, some Ranunculus species produce achenes in several morphological forms, and during fossilization delicate structures maybe destroyed (e.g. spines). After careful morphological consideration it is concluded that the fossil achenes from Belhus Park are Ranunculus parviflorus L., indicating that dry grassland or disturbed ground existed in the river catchment. The plant macrofossil assemblages that included the Ranunculus parviflorus achenes were dominated by waterside, damp ground, and aquatic taxa. It is probable that flowing water transported the achenes from further afield before their incorporation into the fluvial sediments. The identification of these fossils illustrates the importance of considering the morphological characteristics of the achene only and not to make a determination on the nature of the predominant palaeoenvironmental signal from an assemblage.


2000 ◽  
Vol 54 (2) ◽  
pp. 253-263 ◽  
Author(s):  
Michael H. Field ◽  
Felix Y. Velichkevich ◽  
Valerie Andrieu-Ponel ◽  
Phillipe Woltz

The first records of extinct Caulinia goretskyi (Dorofeev) Dorofeev (synonym Najas goretskyi Dorofeev) in western Europe and of Potamogeton occidentalis M.H. Field sp. nov. were obtained from plant macrofossil analyses of Middle Pleistocene temperate stage deposits exposed at Trez Rouz, Brittany, France. Palynological assemblages recovered suggest correlation with the Holsteinian Stage. This discovery greatly expands the western limit of the paleogeographical distribution of Caulinia goretskyi. The record of Potamogeton occidentalis indicates an affinity with the eastern Asiatic flora, as the fruits resemble those of the extant Potamogeton maackianus A. Bennett. Other extinct Pleistocene species related to P. maackianus have been described, and it is possible to follow the development of this group through the Pleistocene in the European fossil record. These new finds illustrate the importance of a complete paleobotanical approach (both plant macrofossil and palynological analyses). The plant macrofossil assemblages not only provide detailed insight into local vegetation and environment, because they are often not transported long distances (in temperate areas) and can frequently be identified to species level; they can also offer the opportunity to investigate Pleistocene evolutionary trends.


2014 ◽  
Vol 341 ◽  
pp. 216-242 ◽  
Author(s):  
Svetlana Kuzmina ◽  
Duane G. Froese ◽  
Britta J.L. Jensen ◽  
Elizabeth Hall ◽  
Grant D. Zazula

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