Juniperoxylon acarcae Akkemik, 2021

Akkemik, Unal, 2021, A New Species Of Juniperoxylon From The Early Miocene Of Northwestern Turkey, Acta Palaeontologica Romaniae 17 (1), pp. 15-26 : 18-25

Juniperoxylon acarcae Akkemik sp. nov.

Figs. 2-5

Holotype. AGUD08 .

Repository. The Department of Forest Botany, Faculty of Forestry, Istanbul University-Cerrahpasa, Istanbul, Turkey.

Etymology. The epithet “ acarcae ” originates from the surname of Dr. N. Neslihan Acarca Bayam who worked on the petrified woods in the Galatian Volcanic Province for her PhD in Turkey. It was the first PhD on petrified woods in Turkey.

Plant Fossil Names Registry Number: PFN001814

Type locality. Aşağıgüney Village of the city of Beypazarı in the province of Ankara ( AGU). This region is called Galatian Volcanic Province (GPV) ( Fig. 1 ).

Age. Early Miocene.

Type horizon. Hançili Formation.

Diagnosis: Growth ring boundaries distinct with 2-3 rows of flattened latewood tracheids. False rings commonly present. Transition from earlywood to latewood indistinct. Tracheids generally circular, and intercellular spaces clearly obvious and occur throughout the wood. Normal axial resin canals absent. Axial parenchyma appears both diffuse (in the transition from earlywood to latewood and within the latewood itself) and tangentially zonate. Rays uniseriate, and sometimes partly biseriate. Ray height is 1-6 (max.16) cells. Tracheidal pits on tangential walls common and 1-2 seriate, irregular or slightly alternate. The rays with one cell height conspicuously longer. Transverse end walls of axial parenchyma cells are nodular and smooth. Ray tracheids absent. End walls of ray parenchyma cells nodular and smooth, horizontal walls of rays sparsely pitted. Tracheid pitting in radial walls of the earlywood is uniseriate and biseriate, opposite, frequent, contiguous, and sometimes spaced. Cross-field pitting is cupressoid with 2–3 (-5) pits per cross-field.

Description: Wood anatomical characteristics of the specimen of Juniperoxylon were given as follows:

Transversal section: Growth ring boundaries distinct with 2-3 rows of flattened latewood tracheids. False rings commonly present ( Fig. 3 : a-c). Transition from earlywood to latewood gradual and indistinct. Tracheids generally circular, and intercellular spaces clearly obvious and occur throughout the wood. Normal axial resin canals absent. Axial parenchyma presents and both diffuse (in the transition from earlywood to latewood and within the latewood itself) and tangentially zonate ( Fig. 3 : b (arrows)-c).

Tangential section: Rays exclusively uniseriate, and sometimes partly biseriate ( Fig. 3 : d). Ray height is 2- 6 (max.16) cells ( Fig. 3 : d-e and Fig. 4 : a). Tracheidal pits on tangential walls commonly present, and uni- to biseriate, irregularly spaced or slightly alternate ( Fig. 3 : e-f). The rays with one cell height conspicuously longer ( Fig. 3 : d-e). Transverse end walls of axial parenchyma cells are nodular and smooth ( Fig. 4 : b-d).

Radial section: Ray tracheids absent. Tracheid pitting in radial walls of the earlywood is uniseriate and biseriate, opposite, frequent, contiguous ( Fig. 4 : e-f), and sometimes spaced ( Fig. 5 : c). Crassulae sometimes presents ( Figure 4 : f). End walls of ray parenchyma cells nodular and smooth, and horizontal walls of rays sparsely pitted ( Figure 5 : a-d). Indenture rarely visible ( Figure 5d ). Cross-field pitting is cupressoid with 2–3 (-5) pits per cross-field ( Fig. 5 : e-g).

Discussion: According to the discussion by Ruiz and Bodnar (2019), the features of distinct growth ring boundary, narrow latewood band, common spaces among tracheid, presence of pits on tangential walls of tracheids, presence of diffuse and/or zonate axial parenchyma, cupressoid or taxodioid type of cross field pits, low height of rays, generally nodular end walls of axial parenchyma, and homocellular rays are the main characteristics of Juniperoxylon . Due to having very close wood anatomical characteristics with Ruiz and Bodnar (2019) ’s description, the present fossil specimen was identified as Juniperoxylon . Based on the differences in the characteristics of the fossil species ( Table 1 ), the following identification key was prepared to find the exact place of the present Juniperoxylon species:

1A. Ray tracheids present

2A. Cross-field pits 4-6 cupressoid; end walls of axial parenchyma cells smooth; radial tracheidal pitting spaced and contiguous> Protojuniperoxylon ischigualastense Bonetti, 1966 emend. Bodnar & Artabe, 2007

2B. Cross-field pits 1-3 cupressoid and taxodioid; end walls of axial parenchyma nodular; radial tracheidal pits sparse> Juniperoxylon rhenanum van der Burgh 1973

1B. Ray tracheids absent

3A. Axial parenchyma absent or scarce, if present, diffuse; Ray parenchyma horizontal walls smooth; 4-6 pits per cross-field; radial tracheidal pitting spaced and contiguous> Protojuniperoxylon maidstonense ( Stopes, 1915) Eckhold, 1923

3B. Axial parenchyma common.

4A. Zonate axial parenchyma present

5A. Cross-field pits only taxodioid; 2-6 pits per cross-field; end walls of axial parenchyma smooth or irregularly pitted; ray height 1-14 cells; horizontal end walls of rays smooth or rarely pitted> Juniperoxylon breviparenchmatosum Watari & Nishida 1973

5B. Cross-field pits only cupressoid, and 1-6 per cross-field.

6A. Horizontal walls of rays smooth; ray width uniseriate and rarely partly biseriate; end walls of axial parenchyma smooth or nodular; radial wall pitting uniseriate, rarely bi-to triseriate pits opposite, and spaced> Juniperoxylon pachyderma (Göppert, 1850) Kräusel, 1949

6B. Horizontal walls of rays distinctly pitted.

7A. Radial wall pitting exclusively uniseriate, horizontal walls of rays distinctly pitted; ray width uniseriate; transversal end walls of axial parenchyma smooth> Juniperoxylon pottoniense ( Stopes, 1915) Kräusel, 1949

7B. Radial wall pitting uni-to biseriate; transversal end walls of axial parenchyma nodular

8A. Tracheidal pits on radial walls often frequent and contiguous; rays uni- to biseriate; crassulae rarely present, end walls of axial parenchyma nodular and smooth; end walls of rays nodular and smooth; horizontal walls of rays sparsely pitted> Juniperoxylon acarcae Akkemik sp.nov.

8B. Spacing of radial tracheidal pits sparse; rays uniseriate; crassulae present; ray parenchyma horizontal walls distinctly pitted> Juniperoxylon juniperoides (Kownas, 1951) Huard, 1966

4B. Zonate axial parenchyma absent, axial parenchyma only diffuse.

9A. Axial parenchyma scarce; ray heights 2-34 cells; ray parenchyma horizontal walls distinctly pitted; 1-2 (3-4) pits per cross-field; radial tracheidal pitting spaced but not contiguous> Juniperoxylon zamunerae (Bodnar et al., 2015) Ruiz & Bodnar 2019

9B. Axial parenchyma present, abundant, and diffuse; ray height up to 18 cells.

10A. Ray parenchyma horizontal walls smooth; end walls of axial parenchyma cells nodular; ray heights 1-5 cells> Juniperoxylon wagneri Süss & Rather 1998

10B. Ray parenchyma horizontal walls sparsely or distinctly pitted; Ray heights up to 18 cells.

11A. Horizontal walls of ray parenchyma sparsely pitted; rays uniseriate and occasionally biseriate; axial parenchyma abundant; crassulae present> Juniperoxylon schneiderianum Dolezych 2016

11B. Horizontal walls of ray parenchyma distinctly pitted; rays uniseriate; axial parenchyma present; crassulae absent> Juniperoxylon turonense Houlbert, 1910

According to the identification key and the given characteristics in Table 1 , the new fossil Juniperoxylon species has differences from all former fossil species.

Juniperoxylon zamunerae (Bodnar et al., 2015) Ruiz & Bodnar, 2019 differs from the new species in having scarce and diffuse axial parenchyma, and 2-34 cells height of rays.

Protojuniperoxylon maidstonense ( Stopes, 1915) Eckhold, 1923 differ from the present specimen in having scarce axial parenchyma and predominantly uniseriate tracheidal pitting on radial walls, and 4-6 cupressoid pits per cross-field ( Bodnar and Artabe, 2007).

Juniperoxylon wagneri Süss & Rather 1998 , Protojuniperoxylon ischigualastense Bonetti, 1966 emend. Bodnar & Artabe, 2007 , and J. schneiderianum Dolezych, 2016 differ from the new specimen in having only diffuse axial parenchyma.

Juniperoxylon breviparenchmatosum Watari & Nishida, 1973 differs from the new species in having only taxodioid type cross-field pits.

Juniperoxylon rhenanum van der Burgh, 1973 differs from the new species in having 1-3 cupressoid and taxodioid cross-field pits, space of radial tracheidal pits, much longer rays (1–40 cells), and crassulae formation.

The closest fossil species are Juniperoxylon pachyderma (Göppert, 1850) Kräusel, 1949 , J. juniperoides (Kownas, 1951) Huard, 1966 , and J. pottoniense ( Stopes, 1915) Kräusel, 1949 . These three fossil species have only spaced radial tracheidal pits. The new fossil species has both spaced and contiguous radial tracheidal pits. J. pachyderma and J. juniperoides have also crassulae formation, and J. pottoniense has exclusively uniseriate pits on radial walls of tracheids.

Based on these differences, the specimen was described as a new Juniperoxylon species and named Juniperoxylon acarcae Akkemik sp. nov. The descriptions of Juniperus from Hoçaş Fossil site ( Akkemik et al., 2016) and from Aşağıgüney Fossil site ( Acarca Bayam et al., 2018) were compared with the new species and results showed that they both had very similar features. It can be concluded that the new species, Juniperoxylon acarcae Akkemik sp.nov. has an area through the valley between Beypazarı- Aşağıgüney Village and Seben-Kozyaka Village ( Fig. 1 ).

Affinities: The fossil Juniperoxylon descriptions (e.g.Vaudois and Privé, 1971; Bodnar and Artabe, 2007; Kłusek, 2014; Akkemik et al., 2016; Dolezych, 2016, Acarca Bayam et al., 2018) revealed that this type of wood is closely related to modern Cupressaceae due to the the presence of “ abietinean tracheid pitting, distinctly pitted ray cell walls, axial parenchyma and cupressoid cross-fields ”.

In Cupressaceae , normal resin canals and helical thickenings are also absent. When some fossil species such as J. zamurense are related to different modern genera, Chamaecyparis Kurz. , Cupressus L., Fitzroya Lindl. and Juniperus ( Ruiz and Bodnar, 2019) , the new species, Juniperoxylon acarcae , is closely related to the modern Juniperus . A comparison of the features of the new fossil species with the five modern Juniperus species in Turkey, which are native, and two similar species given in Esteban et al. (2004), which are Juniperus saltuaria Rehder et E.H. Wilson from south of China and Tibet and Juniperus thurifera L. from the western Mediterranean Basin, showed the highest similarities. However, Juniperus foetidissima Willd. has both cupressoid and taxodioid cross-field pits, and Juniperus saltuaria has not marginal and metatraheal axial parenchyma, therefore, these two species slightly differ from the fossil species and the other five modern Mediterranean species ( Table 2 ). Wood features demonstrated that both fossil and modern species are rather close to each other, and therefore, the fossil species may be evaluated as a possible ancestor of the modern species in the Mediterranean basin.

Possible growing site conditions: The described Juniperoxylon acarcae Akkemik sp. nov. is a forest tree of the Galatian Volcanic Province (GVP). The new species was one of the elements within a rich woody flora of GVP ( Akkemik et al., 2016; Acarca Bayam et al., 2018). The early Miocene trees of Pinus L., Juniperus, Cedrus Trew. , Ulmus L., Zelkova Spach. , Liquidambar L., and Acer L., grow under the conditions of VU0, and VU5 to VU 7 in GVP. These vegetation units (VU) classify that VU0 is subtropical, moist or dry light forests, VU5 is well-drained lowland forests, VU6 is well-drained upland forests, and VU7 is well-drained (lowland and) upland conifer forest.

The Juniperoxylon acarcae stems are autochthonous in the field. The other autochthonous early Miocene trees are Quercus Sect. Ilex , palms (later they were identified as Palmoxylon sp. cf. Trachycarpus by Iamandei et al., 2018), Liquidambar and Salix /Populus in Hoçaş Fossil Site ( Akkemik et al., 2016). Because these fossil woods are found in their original positions in the field, to interpret their life conditions is more satisfactory. The presence of these riparian and lowland trees may suggest that the growing area of Juniperoxylon acarcae trees was a forest having an open, well-drained lowland growing conditions.

Figures

Fig. 2 The type specimen (AGUD08). These are remaining pieces from AGUD08 after taking three thin sec- tions and storied at the Department of Forest Botany, Faculty of Forestry, Istanbul University-Cerrahpasa.

Fig. 3 The thin sections of Juniperoxylon acarcae Akkemik sp. nov. a) Transversal section with false rings and without resin canals, b) Marginal (zonate) axial parenchyma (arrows) and spaces between tracheids, c) Spaces between tracheids, and diffuse axial parenchyma cells, d) Tangential section with uni-to partly biseriate rays, e) Uniseriate pits on tangential walls of tracheids, f) Biseriate and alternate pits on tangential walls of tracheids.

Fig. 4 The thin sections of Juniperoxylon acarcae Akkemik sp. nov. a) Tangential section with short rays, b-d) Nodular and smooth end walls of axial parenchyma, e) Mostly uniseriate and sometimes biseriate pits on radial walls of trache- ids (arrows), f) Frequent uniseriate pits and crassulae formation (arrows).

Fig. 5 The thin sections of Juniperoxylon acarcae Akkemik sp. nov. a) Smooth end walls of rays (arrow), b-c) Slightly dentate end walls of ray, and sparsely pitted horizontal walls of rays, d) Indenture (vertical arrow) and sparsely nodular horizontal walls of rays (horizontal arrow), e-g) Cupressoid type cross-field pits, 2-5 pits per cross-field.

Fig. 1 The location map of the studies samples in Turkey, and the generalized stratigraphic section of the region covering the western parts of the Galatia Massif (Akbaş et al., 2002) and zone of fossils (Hançili Formation). The detailed geological structure of the area was given in Akkemik et al. (2016) and Acarca Bayam et al. (2018).

Tables

Table 1 Comparison of the new species with the former fossil species (Ruiz and Bodnar, 2019)

Fossil species	Age; Country	Pits on radial tracheidal walls		Arrangement of multiseriate pits	Axial parenchyma		Ray height	Ray width	Ray tracheids	Horizontal walls of rays	Number and type of cross-field pits	Crassulae
					Type	End walls
Juniperoxylon acarcae Akkemik sp. nov.	Early Miocene; Turkey	Uniseriate, sometimes biseriate	Frequent, contiguous	Opposite	Diffuse, and zonate	Smooth and nodular	1-16	Uniseriate, rarely partly biseriate	-	Smooth or pitted	2-3 (5), cupressoid	±
Juniperoxylon breviparenchymatosum Watari & Nishida, 1973	Eocene; Japan	Uniseriate, biseriate	Spaced	Opposite	Abundant, diffuse, and zonate	Smooth or irregularly thickened	1-14	Uniseriate, rarely partly biseriate	-	Smooth or rarely pitted	2-6, taxodioid	-
Juniperoxylon juniperoides (Kownas, 1951) Huard, 1966	Miocene; Germany	Uniseriate, biseriate	Spaced, contiguous	Opposite	Abundant, diffuse, and zonate	Nodular	1-12	Uniseriate	-	Distinctly pitted	1-4 (6), cupressoid	+
Juniperoxylon pachyderma (Göppert, 1850) Krausel, 1949	Miocene; Germany, Belgium, Netherlands, Poland, Siberia	Uniseriate, rarely biseriate, triseriate	Spaced	Opposite	Abundant, diffuse, and zonate	Smooth or nodular	1-15	Uniseriate, rarely partly biseriate	-	Smooth	1-6, cupressoid	+
Juniperoxylon pottoniense ( Stopes, 1915) Krausel, 1949	Cretaceous-Eocene; England, Denmark	Uniseriate	Spaced	-	Abundant, zonate	Smooth?	1-12	Uniseriate	-	Distinctly pitted	Cupressoid	-
Juniperoxylon rhenanurn van der Burgh, 1973	Miocene; Germany	Uniseriate, biseriate	Spaced	Opposite	Present, diffuse, and zonate	Nodular	1-40	Uniseriate, occasionally biseriate	±	Distinctly pitted	1-3, cupressoid, taxodioid	+
Juniperoxylon schneiderianum Dolezych, 2016	Miocene; Germany	Uniseriate, biseriate	Spaced	Opposite	Abundant, diffuse	Nodular	2-18	Uniseriate, occasionally biseriate	-	Sparsely pitted	2-4, cupressoid, taxodioid	+
Juniperoxylon wagneri Süss & Rather, 1998	Miocene; Germany	Uniseriate, rarely biseriate	Spaced	Opposite	Abundant, diffuse	Nodular	1-5	Uniseriate	-	Smooth	2-8, cupressoid	-
Juniperoxylon zamunerae (Bodnar, Ruiz, Artabe, Morel,& Ganuza, 2015) Ruiz & Bodnar, 2019	Middle Triassic; Argentina	Uniseriate, rarely biseriate	Spaced	Opposite	Scarce, diffuse	Smooth or irregularly thickened	2-34	Uniseriate, rarely partly biseriate	-	Distinctly pitted	1-2(3-4), cupressoid	-
Protojuniperoxylon ischigualastense Bonetti, 1966 emend.Bodnar & Artabe, 2007	Late Triassic; Argentina	Uniseriate, biseriate	Spaced, contiguous	Alternate, opposite	Present, diffuse	Smooth	1-45	Uniseriate, less frequent partly bi- or triseriate	+	Distinctly pitted	2-4, cupressoid	-
Protojuniperoxylon maidstonense ( Stopes, 1915) Eckhold, 1923	Lower Cretaceous; England	Uniseriate	Spaced, contiguous	?	?	?	1-20	Uniseriate, rarely partly biseriate	-	Smooth?	4-6, cupressoid	+