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

Plant Fossil Names Registry Number: PFN000191

Act LSID: urn:lsid:plantfossilnames.org:act:191

Authors: H. Kerp & B. Vörding

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: 116

Illustrations or figures: pl. 19-20

Types

Original diagnosis/description

Bifurcated(?) fronds, bipinnate, with very large pinnules. Pinnules densely spaced, broadly tongue-shaped to rhomboidal apices rounded. Pinna terminals large, tongue-shaped, consisting of several fused pinnules.
Leaves amphistomatic; stomata randomly distributed on upper and lower pinnule surface, abundant on upper pinnule surface and comparatively more abundant on lower pinnule surface. Epidermal cells of upper pinnule surface larger than those of lower pinnule surface. Anticlinal walls very thin. No differentiation into costal and intercostal fields. Stomata randomly distributed and oriented. Guard cells with very prominent stomatal ledges and wood lamellae. Stomatal complexes usually with four subsidiary cells, usually two lateral, slightly weaker cutinised subsidiary cells and two normally cutinised polar cells; lateral neighbouring cells usually longer than guard cells.

Etymology

The epithet refers to the very robust pinnules.

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.