Lepidopteris scassoi Elgorr., Escapa et Cúneo

Plant Fossil Names Registry Number: PFN003087

Act LSID: urn:lsid:plantfossilnames.org:act:3087

Authors: A. Elgorriaga, I. H. Escapa & N. R. Cúneo

Rank: species

Genus:

Reference: Elgorriaga, A., Escapa, I. H. & Cúneo, N. R. (2019): Relictual Lepidopteris (Peltaspermales) from the Early Jurassic Cañadón Asfalto Formation, Patagonia, Argentina. – International Journal of Plant Sciences 180(6): 578–596., link

Page of description: 580

Illustrations or figures: figs 1–7

Types

Original diagnosis/description

Fronds bipinnate to tripinnatifid, lanceolate, with the larger pinnae occurring below the midpoint of the frond. Main rachis bearing 1–3 pairs of intercalary pinnules with entire to undulate margins between adjacent pinnae. Pinnae opposite to subopposite, linear, lanceolate, to narrow triangular, imparipinnate inserted at obtuse to right angles in the basal frond portion and increasingly acute angles toward the frond apex. Pinnules opposite to subopposite, with a decurrent fully attached base and obtuse apex. Pinnules inserted at subacute to acute angles, with entire to deeply dissected margins and basalmost lobes usually inserted to the pinnae rachis. Venation catadromous and pinnate with a prominent midvein; secondary veins opposite to subopposite, emerging at acute angles reaching the margins or lobes; third-rank veins rare, mostly near the margins. Fronds amphistomatic, with stomata more abundant on the lower leaf surface (0.5–0.7∶1 adaxial/abaxial ratio). Stomata randomly oriented, monocyclic, with a ring of 4–9—usually 7—trapezoidal subsidiary cells bearing strong hollow papillae oriented toward, and partially occluding, the stomatal pit (papillae usually absent on rachides). Guard cells sunken, weakly cutinized. Ordinary epidermal cells straight walled, papillate, and polygonal isodiametric on pinnule lamina to more or less longitudinally elongate above rachis or pinnule midvein. Rachis mostly smooth, without macroscopic scales or lumps but with irregular epidermal pattern. Stomata on main rachis scarce, with subsidiary cells being commonly nonpapillate and not forming a ring.

Etymology

The species is dedicated to the Argentinian geologist Roberto Scasso for his continued work on numerous Patagonian localities in general and on the Cañadón Asfalto Basin in particular.

Stratigraphy

Jurassic, Lower Jurassic, Toarcian
Cañadón Asfalto Formation.

Locality

Argentina
Pomelo locality in Chubut Province, Patagonia.