Acer tricuspidatum A.BRAUN

Martinetto, Edoardo, Bertini, Adele, Mantzouka, Dimitra, Natalicchio, Marcello, Niccolini, Gabriele & Kovar-Eder, Johanna, 2022, Remains Of A Subtropical Humid Forest In A Messinian Evaporitebearing Succession At Govone, Northwestern Italy - Preliminary Results, Fossil Imprint 78 (1), pp. 157-188 : 172-173

cf. Acer tricuspidatum A.BRAUN in Bronn 1838 emend. Walther 1972

Pl. 4, Fig. 6

M a t e r i a l. A leaf from layer GLA20 (MPTA 13366), assigned to Acer tricuspidatum by Cimino et al. (2016).

D e s c r i p t i o n. A probable palmately three-lobed leaf, only the central lobe is almost complete, lateral lobes probably much smaller and shorter than central one; petiole not preserved, l × w about 64 × 47 mm; margin poorly preserved, probably serrate; venation actinodromous with 3 major veins arising at the base of the lamina, running into the lobe apices; exmedially from the lateral main veins 1–2 further delicate and short veins originate at the base running along the leaf margin; secondary veins probably brochidodromous, widely spaced, arising at medium steep angles; intersecondaries occasionally present; exmedial veins originating from lateral main veins looping near margin; tertiaries percurrent, obtuse to midvein.

R e m a r k s. Leaves with comparable outline and venation are common in the local Pliocene sediments and have been assigned to Acer tricuspidatum ( Martinetto 2003, Ciangherotti et al. 2007), a fossil-species already reported from the Messinian of the Alba area ( Martinetto et al. 2000, Kovar-Eder et al. 2006, Cimino et al. 2016). The same name was applied by Zidianakis et al. (2020) to very similar leaves from Crete. The prevalence of rounded forms in these taphocoenoses, rather than forms with narrow and longer lateral lobes, corresponds to forms from Germany treated as A. tricuspidatum subsp. lusaticum H.WALTHER by Mai and Walther (1988). Güner et al. (2017) named a leaf with comparable morphology A. ilnicense ILJINSK. Also , Acer pyrenaicum RÉROLLE should be kept in mind for future comparisons ( Kvaček et al. 2020).