A new protocol for the collection and cataloguing of reference material for the study of fossil Cyperaceae fruits: The Modern Carpological Collection

Abstract

Fossil fruits of the species-rich family Cyperaceae (Poales) are frequently found in Cenozoic sediments of Europe and their taxonomical analysis is particularly difficult and poorly practised, because each fossil has to be compared with several tens of modern samples in order to pinpoint its nearest living relatives. This is only possible by using collections specifically prepared for archaeo- or palaeobotanical studies. We illustrate here the current status and organisation of one of these collections, developed in the frame of a more general “Modern Carpological Collection” (MCC) of the Turin University. Recent efforts in sampling, identifying and characterising cyperaceous fruits in Northern Italy permitted the gathering of 411 samples, covering 80% of the ca. 200 species spontaneously growing in this territory. Due to the still dynamic taxonomy, the large number of species and to the broad intraspecific variability of fruit morphology, we kept a very detailed trace of the sample's origin, by indicating whether and how they were related to the herbarium material. Modern samples from soils and sediments have also been collected, being affected by taphonomic processes that make modern fruits more similar and readily comparable to palaeobotanical samples. In order to test the usefulness of the collection for the identification of fossils, we selected some fossil samples of Cyperaceae fruits extracted from Pleistocene and Holocene sediments and we compared them with all the MCC samples containing similar material. The result of this trial demonstrates the advantage in using specimen-rich collections, such as the MCC, for the identification of fossils, against using only the literature and/or specimen-poor reference collections. We suggest that the procedures adopted for the MCC could become a standard protocol in collecting and cataloguing reference material for the study of fossil Cyperaceae fruits. Besides the possible future development of this relatively small and local collection, an even more promising perspective is seen in the networking activity amongst carpological collections, pointing to the compilation of a large worldwide list of comparative material available for archaeo- and palaeobotanical studies. Such an easy access to an abundant reference material would certainly favour the progress of fruit-morphological studies; moreover, the integration with molecular analyses would presumably yield a better definition of the phylogenetic history of the Cyperaceae within a time context.