Tetraclinis salicornioides (UNGER) KVAČEK , 1989

Niccolini, Gabriele, Martinetto, Edoardo, Lanini, Benedetta, Menichetti, Elena, Fusco, Fabio, Hakobyan, Elen & Bertini, Adele, 2022, Late Messinian Flora From The Post-Evaporitic Deposits Of The Piedmont Basin (Northwest Italy), Fossil Imprint 78 (1), pp. 189-216 : 198

Tetraclinis salicornioides (UNGER) KVAČEK, 1989 hypothetic “whole-plant”

Text-fig. 3d, e , Pl. 5, Figs 1–3

M a t e r i a l. Macrofossils of Tetraclinis occurred only at Ciabòt Cagna where its shoot fragments represent some of the most abundant plant remains ( Text-fig. 3d ). Cones are brittle and heavily deformed ( Text-fig. 3e ).

R e m a r k s. According to Kvaček (2007) two species, T. brachyodon and T. salicornioides , were widespread in the Eocene to Pliocene of Europe. The fossils from Ciabòt Cagna can be assigned to T. salicornioides based on the following diagnostic characters ( Kvaček et al. 2000): leaf fusion complete, bract of the seed cone broader than long, mucro typically subcentral to subbasal. Italian macrofloristic records indicate the occurrence of this same species in the pre-evaporitic and evaporitic intervals (fragments of shoots: Martinetto et al. 2000). In the Pliocene, shoots and cones have been recorded abundantly in association, but never in connection ( Martinetto 1999, Macaluso et al. 2018). The origin of both shoots and cones from the same “whole-plant” is supported by the respective morphological correspondence to the same parts of fossil specimens described by Kvaček (1989), in which cones are connected to shoots. The stratigraphic distribution of the occurrences suggests that T. salicornioides must have persisted in the NW Italian flora throughout the Messinian and Zanclean.

Subfamily Taxodioideae ENDL. ex K.KOCH, 1873 and/or

Subfamily Sequoioideae SAXTON, 1913

Taxodioideae / Sequoioideae gen. et sp. indet.

Pl. 1, Figs 1, 4–11

M a t e r i a l. Pollen grains from the Govone, Pollenzo,

Sioneri, Ciabòt Cagna sections. No macroremains were found.

R e m a r k s. Pollen grains generally are well preserved but difficult to recognize at the genus or species level in the absence of SEM analyses ( Hernandéz-Castillo et al. 2005, Sokolova et al. 2017, Bouchal and Denk 2020). In this study, only Taxodium / Glyptostrobus - type (Pl. 1, Figs 10, 11) and Sequoia - type (Pl. 1, Fig. 1) are distinguished based on, e.g., size and shape of papillae. The other pollen grains referable to Taxodioideae and Sequoioideae subfamilies, but with uncertain morphological characteristics, have been grouped in the category Taxodioideae / Sequoioideae undiff. (Pl. 1, Figs 4–9).

Taxodium / Glyptostrobus - type and Taxodioideae / Sequoioideae undiff. are present in all four sections, while Sequoia - type has been recognized in all sections except in Pollenzo. This latter pollen type is always present in small quantities in Govone and Sioneri, but only a single pollen grain was found in Ciabòt Cagna. Taxodium / Glyptostrobus - type and Taxodioideae / Sequoioideae undiff. appear more abundant in the sections of Govone and Pollenzo than in those of Sioneri and Ciabòt Cagna.

Taxodioideae / Sequoioideae undiff. could represent a few genera of Taxodioideae ( Taxodium , Glyptostrobus , and Cryptomeria D.DON ) or Sequoia . Since the different genera of Taxodioideae or Sequoia do not represent the same ecological niche nowadays, vegetational reconstruction is even more challenging. For example, it includes, e.g., Taxodium and Glyptostrobus , typical of a swampy environment, and Sequoia , which instead nowadays lives on better drained substrates.

Figures

Text-fig. 3. Examples of plant macrofossil assemblages from post-evaporitic sections. a: bedding plane from Ciabòt Cagna covered by impressions of plant parts, with dominance of leaves of cf. Oleinites liguricus M.SACHSE, MCEA-P05038. b: waterloggedcompressed seeds of Toddalia latisiliquata (R.LUDW.) H.-J.GREGOR sieved out of a bulk sediment sample from Pollenzo, MGPT- PU141033. c: millimeter-sized, waterlogged-compressed seeds of Sambucus pulchella C.REID et E.REID with abundant cracks, probably formed during both diagenesis and extraction of the fossils (bulk sediment sample from Ciabòt Cagna), MGPT-