Juniperoxylon ( Houlbert, 1910 ) Kräusel, 1949

Ruiz, Daniela P. & Bodnar, Josefina, 2019, The oldest record of Juniperoxylon, a cupressaceous fossil wood from the Middle Triassic of Argentina, Acta Palaeontologica Polonica 64 (3), pp. 481-488 : 482-484

publication ID	https://doi.org/ 10.4202/app.00597.2019
persistent identifier	https://treatment.plazi.org/id/0202CF01-D16F-FFCE-F168-DCDAFDC71325
treatment provided by	Felipe
scientific name	Juniperoxylon ( Houlbert, 1910 ) Kräusel, 1949
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Genus Juniperoxylon ( Houlbert, 1910) Kräusel, 1949

Type species: Juniperoxylon turonense Houlbert, 1910 ; Miocene , Touraine, France .

Juniperoxylon zamunerae ( Bodnar, Ruiz, Artabe, Morel, and Ganuza, 2015) comb. nov. emend.

Fig. 2 View Fig .

2015 Cupressinoxylon zamunerae ; Bodnar et al. 2015: 149–150,

fig. 5A − O.

Type material: Five pieces of different trunks and their thin sections. Holotype: PBSJ 828. Paratypes: PBSJ 827; PBSJ 829 − 831. There are three thin sections for each of the three sections ( RLS, TLS, TS) used for anatomical studies .

Type locality: La Tinta creek , Barreal area , Barreal-Calingasta depocenter, Cuyo Basin, San Juan Province, Argentina .

Type horizon: EF6 and EF7, lower member of Cortaderita Formation, Ladinian (Middle Triassic) ( Bodnar et al. 2019).

Emended diagnosis.—Abrupt transition from earlywood to latewood, narrow band of latewood. Abietinean radial pitting. Conspicuous torus. Axial parenchyma scarce, with smooth or irregularly thickened transverse end walls. Cross-fields with 1 − 2 oculipores of cupressoid type in one radial row. Homocelullar, mainly uniseriate rays of medium height.

Description.—Homoxylic and pycnoxylic seconday xylem. Transversal section: growth rings boundaries are distinct, with 1−3 cells of latewood (abrupt transition) ( Fig. 2A View Fig 1 View Fig ). Tracheids are quadrangular in outline ( Fig. 2A View Fig 1 View Fig ). Tangential diameter of tracheids is 26.5 μm (10.9−48.9 μm), and tracheid walls are 7.4 μm (4.2−10.9 μm) thick. Tracheid radial diameter is 34.5 μm (15.7−61 μm) in earlywood. Axial parenchyma is scarce ( Fig. 2A View Fig 1 View Fig ). Rays are separated from each other by 3 (1−6) rows of tracheids.

Radial longitudinal section: the wood has abietinean radial pitting, pits are circular, bordered, spaced (Cp = 21.4) and predominantly uniseriate (Si = 1), with occasional biseriation ( Fig. 2A View Fig 3, A 4). Only a few contiguous pits were observed. When biseriation occurs pits are opposite. Pits are 18.9 μm (13.1−25.5 μm) in radial diameter and 17.9 μm 14.9−22.6 μm) in vertical diameter, and pit apertures are 3.9 μm (3.2−4.6 μm) in vertical diameter. Torus is clearly seen Fig. 2A 2 View Fig , A 12).

Rays are homocellular and parenchyma cells are rectangular (procumbent) with distinctly pitted horizontal and end walls (nodular) ( Fig. 2A View Fig 8, B). In some parts of the samples this character is hardly visible because of the poor preservation. End walls are straight (vertical or oblique) or occasionally concave or convex (“indented” in the original diagnosis). In some rays, marginal ray parenchyma cells have an irregular shape giving the appearance of ray tracheids ( Fig. 2A View Fig 9, A 10). These cells are higher, 24.3 μm 20.7−31.2 μm), than the other ray cells which are 14.9 μm 7.3−21.3 μm) high, but they are still of procumbent type. There are one or two (up to four) oculipores of the cupressoid type per cross-field (sensu IAWA 2004) ( Fig. 2A View Fig 5 −A 7, A 13), with an oblique aperture of 5.8 μm (3.9−7.8 μm) in vertical diameter.

Tangential longitudinal section: rays are mostly uniseriate (93.3%) but some of them are partially biseriate (6.7%) Fig. 2A View Fig 11). Rays are 10 μm (1−34) cells and 210 μm (52−751) high. Ray cells are circular in tangential view and the lumen has a width of 11.1 μm (5.3−18.8 μm), with walls of 3.5 μm 2.3−4.8 μm) thick. Axial parenchyma is scarce and diffuse. The transverse end walls of the axial parenchyma are smooth or irregularly thickened ( Fig. 2A View Fig 11).

Stratigraphic and geographic range.—Ladinian, Middle Triassic, San Juan Province, Argentina.