Cupressinoxylon sp.

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 : 167-168

cf. Cupressinoxylon sp.

Text-fig. 6a, b

M a t e r i a l. Fossil wood specimen MGPT-PU141105 (Repository: MGPT-PU), small part of MGPT-PU141105 specimen and 3 slides. Specimen MGPT-PU141106 collected by P. Damarco (Repository: MGPT-PU), small part of MGPT-PU141106 specimen and 3 slides.

M a c r o s c o p i c d e s c r i p t i o n. The slides MGPTPU141105 come from a permineralized woody axis of variable color, mostly from very dark (blackish) to light grey; approximate dimensions in cm: 150 × 60 × 30. The longer axis was in a horizontal position, still in situ within the plantrich bed GLA10. The slides MGPT-PU141106 come from a permineralized wood sample, mostly of brownish-grey to light grey color; approximate dimensions in cm: 30 × 10 × 5. The sampling place was indicated in the area where the plant-rich bed GLA19 crops out.

M i c r o s c o p i c d e s c r i p t i o n. Transverse section: Distinct growth ring boundaries, axial tracheids of polygonal to roundish section. Axial parenchyma observed.

Tangential section: not observed due to poor preservation.

Radial section: Absence of ray tracheids, bordered pits (tracheid pitting in radial walls) not observed, cross field pits not observed, nodular end and thick (and possibly pitted) horizontal walls of ray parenchyma.

R e m a r k s. Although the anatomical characters are not sufficient for a detailed identification, the absence of resin canals excludes Pinaceae , while the presence of nodular end and thick (and possibly pitted) horizontal walls of ray parenchyma cannot be found in the former Taxodiaceae ; rather, they can be found in the Cupressoideae . For the observed – relatively small – roundish tracheids and the absence of radial (and axial – even traumatic) resin canals this wood can possibly be assigned to Cupressinoxylon as emended by Dolezych (2005), on the basis of the description by Göppert (1850). The absence of callitroid thickenings excludes Callitrixylon PRIVÉ, the presence of circular tracheids observed is not related to taxonomy, but to ecology, therefore Tetraclinoxylon GRAMBAST is also excluded. The co-occurrence of nodular end and thick (and possibly pitted) horizontal walls of ray parenchyma is not found in Widdringtonioxylon GREGUSS , Libocedroxylon CHUDAJB. , Thujoxylon (UNGER) HARTIG and Chamaecyparioxylon CHUDAJB. Palaeocallitroxylon GREGUSS is regarded as a junior synonym of Juniperoxylon HOULBERT. The latter genus could represent our fossil, judging from the co-occurrence of nodular end and thick (and possibly pitted) horizontal walls, but its nomenclatural priority is a matter of discussion ( Philippe and Bamford 2009). In our case unfortunately, the tangential section does not provide a view on the pitting of the cross walls of ray cells, which is crucial, and should be scalariform in case of this genus ( Gothan 1905).

Botanical affinities. Specific genera in Cupressaceae s. l. ( Román-Jordán et al. 2017) have nodular end, and thick and pitted horizontal walls of ray parenchyma: Diselma

HOOK.F., Fitzroya HOOK.F. ex LINDL. , Calocedrus KURZ , Chamaecyparis SPACH , Hesperocyparis BARTEL et R.A.PRICE , Cunninghamia . The poor preservation of the here-described wood does not allow us to suggest a relationship to an extant genus.

Figures

Text-fig. 6. Transmitted light microphotographs of permineralized wood from Govone. a, b: cf. Cupressinoxylon sp., radial section, MGPT-PU141105, a – nodular end of ray parenchyma (arrow), b – thick and pitted horizontal walls of ray parenchyma (arrow). c–f: Pinaceae gen. et sp. indet., MGPT-PU141107, c – abnormal discoloration due to ecological disruptions (radial section), d – rays up to 10 cells high, uniseriate, partly biseriate (black arrow), intercellular spaces observed (white arrows) (tangential section), e – large, thick-walled axial resin canal with more than 9 epithelial cells observed, axial resin canal diameter>60 Μm (transverse section), f – spiral thickenings due to compression (white arrow) (radial section).