Glyptostroboxylon rudolphii DOLEZYCH et BURGH, 2004

Akkemik, Ünal & Bayam, Nevriye Neslihan Acarca, 2019, The First Glyptostroboxylon And Taxodioxylon Descriptions From The Late Miocene Of Turkey And Palaeoclimatological Evaluation, Fossil Imprint 75 (2), pp. 268-280 : 270-272

Glyptostroboxylon rudolphii DOLEZYCH et BURGH, 2004

S t u d i e d m a t e r i a l. SAK14 and SAK18

(Repository: Fossil collection of the Department of Forest

Botany, Faculty of Forestry , Istanbul University, Istanbul, Turkey ).

H o r i z o n. Hüyükköy Formation.

A g e. Late Miocene (Tortonian).

L o c a l i t y. Çankırı: The village of Sakarcaören near to the town of Orta (latitude and longitude coordinates are 40°36′42.46″ N and 33°9′16.14″ E) .

D e s c r i p t i o n. The studied specimen sizes are: height 7.5–8.5 cm, width 4.5–7 cm and lengths 2.5–4 cm in SAK14 and SAK18, respectively. The microscopic description of the woods is given below:

Transverse Section (TS): Annual rings are 0.25–1 mm, with indistinct boundaries marked by only 1–2 rows of radially flattened latewood tracheids. Earlywood/latewood transition gradual, and no direct transition from earlywood to latewood was observed. No resin canals were observed. Tracheids are usually polygonal (Pl. 1, Fig. 1). The tangential and radial diameters of the tracheids are 37 (21–47) μm and 44 (24–63) μm in the early part of the earlywood and 34 (22–49) μm and 21 (7–36) μm respectively, in the final rows of latewood. Double wall thickness is 5 (1–10) μm in earlywood and 6 (4–9) μm in latewood ( Tab. 1). The number of tracheids between two rays is 2–14. Axial parenchyma abundant, and diffuse.

Tangential Longitudinal Section (TLS): Rays are uniseriate (Pl. 1, Fig. 2, right), and very rarely partly biseriate (Pl. 1, Fig. 2), cells very low 1–4(–7) in height (Pl. 1, Fig. 2). Ray width is 18 (12–23) μm and height is 53 (21–121) μm ( Tab. 1). Axial parenchyma cells have thin smooth transverse walls (Pl. 1, Fig. 3).

Radial Longitudinal Section (RLS): Rays are homogeneous. Tracheidal pits small in diameter, and in 1–3 horizontal rows (Pl. 1, Fig. 4). No helical thickenings observed, and crassulae only slightly visible. Cross- field pits mostly with significantly reduced border, i.e. “glyptostroboid” (similar to pinoid as in IAWA Committee 2004) and sometimes taxodioid, with 2–3 (1–4) pits per cross-field, and arranged in 1–2 rows, regular or more often irregular (Pl. 1, Figs 5, 6).

C o m p a r i s o n. According to the emended diagnosis given by Dolezych and Van der Burgh (2004), Glyptostroboxylon has clear growth rings having wider tracheids in earlywood than in latewood, 1–3(–4) rows of tracheidal pitting, axial parenchyma smooth to moderately thick with pitted end walls, homogeneous rays and predominantly glyptostroboid, also cupressoid and taxodioid type of cross-field pits. In the wood studied here, growth ring borders are visible, cross-field pits are predominantly glyptostroboid, (sometimes taxodioid), and ray height is relatively low. As it has very similar features to Glyptostroboxylon , we attributed the wood to this fossil genus. Sequoioxylon and Taxodioxylon are the other similar genera. In Sequoioxylon and Taxodioxylon , annual ring borders are clearly distinct, cross-field pits are predominantly taxodioid and often arranged in one horizontal row, ray heights are variable but generally much higher than in Glyptostroboxylon ( Süss and Velitzelos 1997, Dolezych and Van der Burgh 2004, Teodoridis and Sakala 2008, Akkemik et al. 2009, 2017, Koutecký and Sakala 2015). Recently, Akkemik et al. (2017) identified Glyptostroboxylon from the middle – late Burdigalian (early Miocene) from the central area of the GVP. Kasaplıgil (1977) and Denk et al. (2017b) collected leaf and cone fossils of this genus from the early Miocene fields of the Güvem area. The present description is from the late Miocene (Tortonian) of the eastern GVP.

Two fossil-species of Glyptostroboxylon were described as Glyptostroboxylon tenerum (KRAUS) CONW. and Glyptostroboxylon rudolphii DOLEZYCH et BURGH ( Text-fig. 4 ). The main differences between these two fossil-species are in the pitting on the tracheid radial walls. If the pits are biseriate with crassulae, the wood is evaluated as G. rudolphii . In contrast, wood having uniseriate pits on the tracheid radial wall but without crassulae, is accepted as G. tenerum ( Dolezych and Van der Burgh 2004, Teodoridis and Sakala 2008). Because tracheid pitting can be up to 3 vertical rows and abundant, cross-field pits are generally 1–4 predominantly glyptostroboid but also taxodioid types, our woods are identified as Glyptostroboxylon rudolphii .

Dolezych and Van der Burgh (2004), Teodoridis and Sakala (2008) and Dolezych (2011) explained that two species of Glyptostroboxylon are represented by two different genera. Glyptostroboxylon tenerum (KRAUS) CONW. is represented by modern Cunninghamia R.BR. in RICH., and Glyptostroboxylon rudolphii DOLEZYCH et BURGH by modern Glyptostrobus . The modern Glyptostrobus has only one species ( G. pensilis K.KOCH ) growing in the swamp forests of Vietnam and China ( Eckenwalder 2009, Farjon 2010; Text-fig. 4 ).

Figures

Text-fig. 4. Distribution of Glyptostroboxylon rudolphii in the Miocene (solid circles) and Glyptostrobus pensilis at present (open circles). It grows in the subtropical swamps of Vietnamese and China (Eckenwalder 2009, Farjon 2010).