Eucommia europaea

Martinetto, Edoardo & Macaluso, Loredana, 2018, Quantitative Application Of The Whole-Plant Concept To The Messinian - Piacenzian Flora Of Italy, Fossil Imprint 74 (1 - 2), pp. 77-100 : 90-92

Eucommia europaea whole - plant

Eucommia europaea MÄDLER (fruit); Eucommia (pollen); possibly also cf. Eucommia (wood) Pl. 1, Figs 1–4

M a t e r i a l. Fruits from Monte Tondo, Messinian (2 specimens). We also considered an almost complete fruit specimen from the Calabrian site Stirone-Laurano (see SP in Text-fig. 1 ). Even though other Pleistocene records (Martinetto 2015) are not detailed here, it should be mentioned that the recent report by Martinetto et al. (2015) includes an early Gelasian occurrence from the Arda- Castell’Arquato – AD3 locality (see CQ in Text-fig. 1 ), whose age was estimated to be around 2.5–2.4 Ma. However, this age was challenged by Crippa et al. (2016), who assigned the deposits, just above the plant-bearing layer, to the base of the Calabrian (i.e. around 1.8 Ma), whereas Monesi et al. (2016) classified this interval as “not interpreted” from a chronostratigraphic point of view. Pollen of Eucommia is rare and found in just a few Messinian – Piacenzian sites.

R e m a r k s. The occurrence of Eucommia in the Neogene of Italy was mentioned by Günther and Gregor (1990) for the Piacenzian locality Santa Barbara, but without description and illustration of the possible fruit specimen (record to be verified). Recently, two fossil fruits (not reported in Martinetto 2015, who described Pleistocene specimens, nor in Teodoridis et al. 2015b) were detected in the Messinian deposit of Monte Tondo. Despite their incompleteness, the winged fruits can be definitely assigned to Eucommia because they show an apparent reticulate pattern of veins and latex filaments over the seed, and a medial vascular strand separating the fertile carpel and the vestigial infertile carpel ( Call and Dilcher 1997). Only a single almost complete fossil fruit (Pl. 1, Fig. 4) was found in Italy so far, and it originates from the late early Pleistocene deposits of Stirone-Laurano.

All the determinable fruit specimens of the late Cenozoic of Europe have been recognized as very similar to Eucommia ulmoides ( Tralau 1963, Call and Dilcher 1997, Kvaček et al. 2008, Manchester et al. 2009), but they were often assigned to a fossil-species named Eucommia europaea MÄDLER , whose actual distinction from the living biological species Eucommia ulmoides has even been questioned ( Tralau 1963). However, the fruits of E. europaea are described as being larger ( Manchester et al. 2009) and the possible associated leaves as more entire-margined ( Kvaček et al. 2008) in comparison to those in the single living species. Four other fossil-species names have been applied to Cenozoic fossil fruits ( E. palaeoulmoides BAJK. also to leaves) from Eastern Europe and Siberia ( Zhilin 1974). Since there is no definite evidence for the occurrence of more than one species of Eucommia in the late Cenozoic of Central and Western Europe, and all the available fruit material (Neogene and Pleistocene) from Italy conforms to the characters of E. europaea , we assign it to this fossil-species.

The picture of this possibly extinct “ Eucommia europaea whole-plant” is supported by the rare Neogene pollen grains identified as “ Eucommia ” ( Bertoldi and Martinetto 1995, Bertini 2010). These occur more abundantly in the Italian early Pleistocene ( Ravazzi 2003: 99), where also fossil woods of cf. Eucommia have been reported ( Pini et al. 2014), although no leaf remains were so far reported from Italian sites. The various fossil remains are useful for the reconstruction of the ancient whole-plant, but in reality the strong similarity of the fossil and corresponding modern parts suggests a close systematic affinity of E. europaea to the modern plant E. ulmoides ( Ying et al. 1993) , whose aspect can be assumed as a model for the “ Eucommia europaea whole-plant” (line of evidence ISA). Considering that the family Eucommiaceae is very isolated within the clades of Garryales ( Stull et al. 2015) , the only possible habitus is the one of the single living species of this family: trees with spirally arranged deciduous elliptic leaves and samaroid fruits.

Figures

Text-fig. 1. Map of northern and central Italy showing the location of the main sites with relevant Messinian to Piacenzian fossil floras. For locality labels see explanation in Table 1.