Glyptostroboxylon Conwentz emend. Dolezych & van der Burgh, 2004

IAMANDEI, STĂNILĂ, IAMANDEI, EUGENIA, VELITZELOS, DIMITRIOS & VELITZELOS, EVANGELOS, 2022, Palaeoxylotomical Studies In The Cenozoic Petrified Forests Of Greece. Part Two - Conifers, Acta Palaeontologica Romaniae 18 (1), pp. 65-111 : 82-86

Genus Glyptostroboxylon Conwentz emend. Dolezych & van der Burgh, 2004

Glyptostroboxylon rudolphii Dolezych & van der Burgh, 2004

82 Material

The studied material is represented by 36 samples of petrified wood, collected from the Aegean area, both from insular and continental part. Thus, some of them were collected from Evros region, from late Oligocene deposits, from Lefkimi - the samples Lfk.1, 56(3), 152, 255, 256, 257, 258, 262, 263, 273, 284, 288 and from Trifili - the samples Tf.5, 9, 15, 23, 27, 45, 47, 50, 137, 309, 314. Also, some samples were collected from early Miocene deposits of Limnos island - the samples numbered with Li.131, 132-2, 205, 471, 474, 474-14, 480, 481, and from Lesbos Island - the samples Lsv.45, 112, 428, 455 and 470.

The studied material is registered as “Velitzelos Collection”, and stored in the Collection of the Faculty of Geology and Geoenvironment, of the NKUA.

Microscopic description

Growth rings – are variable, from low to wide (i.e. from 8-15 cells to over 50 cells), usually with quite abrupt transition from the early-wood to the narrow late-wood, which has 2-3-5 rows of smaller flattened cells, so, the growth rings boundaries are quite distinct, since always the early-wood starts with larger cells. Normal axial resin canals absent.

Tracheids – have polygonal lumen in cross-section in the early-wood, with radial / tangential diameters of (20-)35- 60 / (17-)30-40 μm and the wall thickness of 3-6 μm (double wall); in the late-wood the diameters are quite similar, only in the final 1-3 rows, the tracheids are diminishing, having 8-15 / 10-15 μm in diameters, and the wall thickness reach 7-9 μm the double wall. The tracheids, in cross section, appear regularly arranged in 2-9 radial rows between two successive rays, and intercellular spaces are often present. The density is 1300-1700 tracheids per mm 2. The length of the tracheids is medium to large type, but difficult to measure. The pitting on the radial walls is 1-4 seriate, spaced, in opposite arrangement and often with crassulae. The pits, of bordered type, are round, with (12-)15-20 μm in diameter, with large chamber and round to slightly elliptic aperture. On the tangential walls, few uniseriate smaller pits of 8-9 μm in diameter appear, sometimes localy irregularly biseriate. Helical thickenings absent, but striations sometimes are present on the endings which, sometimes, can be slightly bent. Crassulae sometimes present and, when present, the pits are located in a kind of nest and are slightly molded by the tracheidal wall. Callitroid thickenings not present. Organic deposits absent.

Axial parenchyma – is present and appear in cross section as few smaller cells, in diffuse arrangement, scattered throughout the entire growth ring and usually with some dark content.

83 In vertical section, the string of parenchyma cells shows transverse end-walls thin and smooth to moderately nodular, and also resin content as rare small and black globules or granules, inside.

Rays –appear linear and thin in the cross sections, usually exclusively uniseriate. In tangential section they appear sometimes with biseriate storeys to almost biseriate. Lateral intercellular spaces are often present. The rays are of low type, having 1-10 cells, to mid type, with up to 20 cells, sometimes taller. In radial section the rays are usually homogeneous, with parenchymal ray-cells all procumbent, the marginals taller. The horizontal walls of the ray-cells are smooth, with simple pits, and the end-walls are smooth. Indentures - not visible. The cross-field pitting is of glyptostroboid type, usually having glyptostroboid pits or, sometimes, taxodioid, of 10-12 μm, with round to large-eliptic appertures. They appear as 1-4 pits in one horizontal row in normal cross fields, or 4-6 pits in the taller cross fields, when they are in 2 superposed rows or slightly irregularly arranged. In the late-wood cross fields the pits tend even to cupressoid type as smaller pits, of 6-8 μm, and with inclined lens- like apertures. Sometimes, globules or granules of resin are present inside the ray cells.

Resin canals – are absent.

Mineral inclusions – are absent.

Affinities and discussions

The synthetic description of the above specified 36 specimens provided xylotomical details typical for a cupressaceous wood of ‘taxodiaceous’ type, caracterized by absence of the resin ducts, cross-section and wallthickness of the tracheids and especially by the presence of radial pitting as 1-4-seriate on tracheids, sometimes with crassulae and the cross-field with typical glyptostroboid pits, tending sometimes to taxodioid or even cupressoid aspect. These xylotomical details have been compared with other extant or fossil structures of ‘taxodiaceous’ type, as published by Greguss (1955), Visscher & Jagels (2003), InsideWood (2004 – onwards), Dolezych & van der Burgh (2004), Dolezych (2011) and Wheeler (2011) that suggested us the most possible affinity to Glyptostrobus wood-type. This genus belongs to the family Cupressaceae (s.l.), subfamily Taxodioideae Endl. ex K. Koch - together with Taxodium Rich. and Cryptomeria D. Don , as is presented above. The current Glyptostrobus Endl. has a single species living in a disjunct area in East Asia: G. pensilis (Staunton ex D. Don) K. Koch , (Chinese swamp cypress) in subtropical southeastern China (Fujian, Yunnan) and locally, in northern Vietnam and eastern Laos (Lao PDR) (Greguss, 1955; Earle, 2018).

It typically grows in river banks, ponds and swamps, even in water up to 60 cm deep, similar to the related genus Taxodium , having also ‘cypress knees’ which help the roots to breath. Arguably even before, but surely during the Cenozoic, the distribution of these genera was different than today, they were present in Europe, from 84

where a lot of fossilized wood remains and other vegetative plant parts were found and described. Often, these genera were deeply implied within coal-genesis, the fossil forms of Taxodium and Gyptostrobus probably had a typical and similar behaviour as today preferring the wet environments or even swamps, or peat-bogs (Greguss, 1955; Earle, 2015).

Also, comparing the anatomical structure of the studied specimens with other ‘taxodiaceous’ fossil genera (Greguss, 1967) we observed some similarities also with the fossil forms of Taxodioxylon (Hartig) Gothan , but especially with Glyptostroboxylon Conwentz, 1884 . In fact, the distinction between these fossil genera is sometimes problematic enough, as they have many similar xylotomical details. But, in a more recent revision of these fossil cupressaceous morphogenera (Dolezych & Van der Burgh, 2004) the authors tried to solve this problem and created a new species of Glyptostroboxylon by reviewing the original material described by Kraus (1864), from Wetterau, which was found as comparable with the wood of modern Cunninghamia R.Br. (Dolezych, 2011) , so emending the genus diagnosis. We reproduce here the diagnosis of the genus Glyptostroboxylon Conwentz , emend. Dolezych & van der Burgh, 2004: “Coniferous wood with distinct growth rings. Tracheids in the earlywood wider than in the latewood. On the radial walls of tracheids, pits in 1–3(4) vertical rows. Wood parenchyma with thin and smooth to moderately thick and pitted terminal (horizontal) walls. Rays are homogeneous, mostly uniseriate. Cross-field pits in the early wood are predominantly glyptostroboid, but also some cupressoid and taxodioid pits may be present”.

In our studied specimens we observed and described very similar details regarding the shape of the tracheids in cross-section and their radial pitting as 1-2 to 3-4 vertical rows, spaced or sometimes slightly irregularly arranged; then, the presence of axial parenchyma with smooth to slightly nodular horizontal walls; and the rays, which are uniseriate, often with biseriate storeys, or even as biseriate rays, homogeneous with ray cells all procumbent, tangential walls smooth, and no ray-tracheids; the cross-fields with 1-4 glyptostroboid pits, sometimes tending to taxodioid, more numerous in the marginal fields which are taller and the pits are smaller cupressoid pits arranged in two horizontal rows or slightly irregularly. Such description corresponds to the genus diagnosis.

• Dolezych & van der Burgh (2004), in their revision of Glyptostroboxylon genus, showed that the species Glyptostroboxylon tenerum (Kraus) Conwentz was the initial basionym for the genus (whose former name was Glyptostrobus tener Kraus, 1864 ). This basionim was commented by Seward (1919, p. 198) and by Jurasky (1933), and corrected by Kraüsel (1949), respecting he ICBN Rules of that time. However, he noted the wide variability of the glyptostroboid pits in the cross fields, toward taxodioid or cupressoid type. Now, Glyptostroboxylon tenerum is interpreted as fossil wood of Cunninghamia . In fact, it was known that Gothan (1905) and later, Rudolph (1935), Watari (1948), Süss & Velitzelos (1997) and Fairon-Demaret et al. (2003) have observed an affinitiy between the wood of Glyptostroboxylon tenerum and that of the current Cunninghamia , and the new investigation on the original material from Wetterau, the type-locality, made by Dolezych & van der Burgh (2004), have proved that the affinity of this wood is not to Glyptostrobus , but clearly to Cunninghamia (also Dolezych, 2011).

• In the same paper Dolezych & van der Burgh (2004) described a new species, Glyptostroboxylon rudolphii Dolezych & van der Burgh , designating it as new basionym for the genus Glyptostroboxylon Conwentz emend. Dolezych & Van der Burgh 2004 (cited above, the emended diagnosis). The species name come from the name of a scientist who, first time discussed the affinity of the described fossil wood as Glyptostroboxylon as being to the recent wood of Glyptostrobus not of Cunninghamia (Rudolph, 1935) , observing that the pits in cross field of the studied fossil wood are glyptostroboid and taxodioid, in a random distribution. This new species described, Glyptostroboxylon rudolphii , represents, most probably, the fossil wood of Glyptostrobus europaeus (Brongniart) Unger , which was described on the basis of adpressions of shoots, leaves and cones, and was frequently found in the European Cenozoic formations (Greguss, 1967; Hofman, 1952; Ramanujam, 1960; Zalewska, 1953). Together with their revision of Glyptostroboxylon genus, Dolezych et van der Burgh (2004) described more material of “taxodiaceous wood” in Lusatia (Central Europe) with clear affinity to the current Glyptostrobus . Also, they suggested that many other descriptions of similar coniferous woods previously described by Kräusel (1949), Schönfeld (1952), Kostyniuk (1967), Visscher & Jagels (2003), van der Burgh (1973), could be revised and assigned to Glyptostroboxylon rudol phii.

• Teodoridis & Sakala (2008) identified a Glyptostroboxylon rudolphii , and observed the disproportion between the abundance of leaves and cones and ds of Glyptostrobus in Most Basin ( Czech Republic), and only one specimen of fossil wood found preserved as xylite, rather difficult to identify and attributable to this genus, traditionally considered as the main coal-generating element in “the association of Glyptostrobus ” sensu Kvaček & Bůžek, 1982 (in Kvaček, 1999 and in Teodoridis & Sakala, 2008, p.304).

• Biondi & Brugiapaglia (1991) described a Taxodioxylon gypsaceum on a specimen from the Pliocene of Umbria region, central Italy, having commonly with 4- seriate bordered pits on the radial walls of the tracheids, presumably in early wood and also, axial parenchyma with smooth horizontal walls. In a later work, refering to the same material, Biondi & Brugiapaglia (2000) affirm that the 4-seriate bordered pits are rare, and they are mostly 1- to 2-seriate, and suggested that the wood anatomy of the Dunarobba wood could be similar to the one of the current Sequoia . However, Martinetto (1994) pointed out that in the Dunarobba deposits the conifer foliage, ds and cones belong uniquely to Glyptostrobus europaeus , so we think that a revision of the fossil wood of Dunarobba Fossil Forest is necessary, since we believe that we talk about Glyptostroboxylon rudolphii (also Vassio et al., 2008).

• Also, Ravazzi & Van der Burgh (1995) have identified several wood samples from the Leffe brown coal (Early Pleistocene, N-Italy), and some specimens that were assigned to Glyptostroboxylon tenerum (Kraus) Conwentz , found together with pollen of Glyptostrobus , Chamaecyparis , Picea and Pinus . However, the Leffe wood identifications would need revision too (Vassio et al. 2008), because the described wood shows some characteristics that point to Glyptostroboxylon rudolphii : in the radial walls of earlywood tracheids bordered pits are biseriate, crassulae are present, rays are uniseriate and up to 22 cells high; cross field pits vary from cupressoid to taxodioid and to glyptostroboid (Fairon-Demaret et al., 2003; Richter et al., 2004).

• Some Miocene fossil wood remains described by Iamandei et al. (2001) from Eastern Carpathians (Leucuşeşti- Fălticeni) and by Nagy et al. (2002) from South Apuseni Mts. (Prăvăleni) were identified as Glyptostroboxylon tenerum , but having cross fields with 3-4(- 6) glyptostroboid pits, most probably must be revised to Glyptostroboxylon rudolphii .

• Teodoridis & Sakala (2008) have studied a fragment of sideritized wood from Bílina Mine, from the Most Basin, described as G. rudolphii , having crassulae, large intercellular spaces between ray-cells and cross-field pits exclusively glyptostroboid.

• Vassio et al. (2008), also described G. rudolphii from Middle Pliocene, studying the in-situ stumps from Stura di Lanzo right riverbank, NW Italy, based on their typical features, especially the presence of exclusively glyptostroboid cross-field pits.

• Dolezych (in Erdei et al., 2009), studied the stumps from the Miocene Fossil Forest from the opencast lignite mine of Bükkábrány ( Hungary) and described wood structures atribuable to Glyptostroboxylon Conwentz emend. Dolezych and van der Burgh , as having glyptostroboid cross field pits. This fact is confirmed also by the presence of the organic-rich sediments underlying and embedding the stumps, which provided a high abundance of wood remains, foliage, cones and ds of Glyptostrobus .

• Gryc & Sakala, (2010), studied also the xylotomy of the big trunk of fossil wood found in the Miocene opencast lignite mine of Bükkábrány ( Hungary) and exposed in the Visitor Centre of the Ipolytarnóc Fossils Nature Reserve and, have identified it as Glyptostroboxy-

85

lon rudolphii , having cross-field pits, mainly glyptostroboid.

• Dolezych (2011) made new xylotomical investigations in the Miocene peat formation in Lusatia trying to reconstruct the woody plant communities and described again the presence of G. rudolphii with its typical xylotomical features, besides other taxa.

• Havelcová et al. (2013) have described a G. rudolphii , in the Stump Horizon from the Bílina open cast mine ( Czech Republic), as having the typical glyptostroboid pits in the cross-fields.

• Koutecký & Sakala, (2015) described G. rudolphii from Doupovské hory, Czech Republic, as having glyptostroboid and taxodioid pits (1–2, occasionally up to 4) in cross-field, and low rays, up to 12 cells tall.

• The fossil wood remains signalled by Mustoe (2018) at high latitudes of North America (from Yukon to Elsemere Island and around), were studied by Dolezych et al. (2018) who described more Cretaceous - Paleogene conifers, and between them a Glyptostroboxylon cf. rudolphii and also, a G. tenerum .

• Li et al. (2018), described a new species, a wood from the Paleocene of Carneyville, Wyoming ( US) as Sequoioxylon carneyvillense Li, Jin et Manchester but having cross-fields with 1-4 taxodioid pits and being associated with twigs, fossil leaves and d cone remains, identified as of Glyptostrobus europaeus , we presume it could be a wrong identification, and it is probably a Glyptostroboxylon rudolphii .

• Recently, Akkemik et al. (2017) published a Glyptostroboxylon (of rudophii type) from central Turkey, and then Akkemik et al. (2018; 2019a,b; 2020b) identified G. rudolphii from another sites in Turkey, based on the typical features such as 2-5 pits per cross field, predominantly glyptostroboid, but also taxodioid and, apparently, much higher rays.

• Very important, Mantzouka et al. (2019a) found, presented and redescribed the original material of the holotype of Glyptostrobus europaeus , housed in the collections of the Muséum National d'Histoire Naturelle, Paris, originally collected from the Alonissos Island, Greece, an also, they show that such fossil remains of Glyptostrobus europaeus have been described in several localities in Greece during the Cainozoic up to Pleistocene.

• And, in a recent study on some Miocene material from Bozovici area (SW Romania) was described by Iamandei et al. (2020b) a Glyptostroboxylon rudolphii , as having typical tracheidal radial pitting 1-4-seriate, and 1- 4 glyptostroboid and taxodioid cross-field pits, in horizontal row.

Thus, after this discussion, and based on the synthetic description of a numerous population of samples (39 specimens) collected from the Aegean area, it is obvious that there is a great similarity of the xylotomical characters of our studied specimens with those comprised in the

86 generic and specific diagnosis, and with those showed by the numerous previous identifications, discussed above, as well as with the characters of the curent correspondent, we attribute all the studied specimens to Glyptostroboxylon rudolphii Dolezych et van der Burgh, 2004 , as a perfect fossil equivalent of the extant living fossil Glyptostrobus Endl.