Dicroidium jordanensis Abu Hamad et Kerp in Abu Hamad, Kerp, Vörding & Bandel

Plant Fossil Names Registry Number: PFN000189

Act LSID: urn:lsid:plantfossilnames.org:act:189

Authors: A. Abu Hamad & H. Kerp

Rank: species

Reference: Abu Hamad, A., Kerp, H., Vörding, B. & Bandel, K. (2008): A Late Permian flora with Dicroidium from the Dead Sea region, Jordan. – Review of Palaeobotany and Palynology 149(3–4): 85–130.

Page of description: 113

Illustrations or figures: pls 8–17, 18: 1–6, 8–9; fig. 4

Types

Original diagnosis/description

Fronds small, bifurcated, bipinnate. Primary axis robust and smooth, bifurcating with an angle of approximately 25°. At least two pairs of pinnae are inserted below the bifurcation; frond portions above bifurcation more-or-less ovate in outline, tapering towards the apices and with their greatest width in the middle. Pinnae alternating to suboppositely attached, at angles of between 30° and 70°, bearing up to 17 pinnules at each side. Pinnules normally widely spaced but sometimes overlapping, in alternating or subopposite position; pinnules broadly attached, decurrent, asymmetrical, tongue-shaped to triangular in outline with rounded-to-acute apices pointing towards pinna apices. Basiscopic pinnules more obliquely attached than acroscopic pinnules; basal basiscopic pinnule semi-circular in outline. Pinnae ending in elongated, narrow terminal pinnules usually consisting of 2–3 strongly fused pinnules. Intercalary pinnules occasionally present, asymmetrically triangular and smaller than normal pinnules.
Leaves amphistomatic; stomata more abundant on lower than on upper leaf surface. Cells of upper leaf surface up to twice as large as those on lower surface. Normal epidermal cells isodiametric to elongated, rectangular. Stomatal complexes with two slightly sunken guard cells, partly underlying the adjacent subsidiary cells. Stomatal apparati monocyclic to incomplete dicyclic with a ring of four to seven subsidiary cells; subsidiary cells similarly cutinised as normal cells.

Etymology

The name refers to the Jordan Valley, the rift structure of which the Dead Sea is a part.

Stratigraphy

Permian
Silt and clay layers and lenses, 15.5–16.5m above the base of the Um Irna Formation, Upper Permian.

Locality

Jordan
Wadi Himara, in the incised river valley, ca. 400 m upstream along the southern branch after the main bifurcation at 31° 37′ 55.67″ N and 35° 37′ 15.69″ E.