Tanispermum hopewellense E.M.Friis, P.R.Crane et K.R.Pedersen

Plant Fossil Names Registry Number: PFN002000

Act LSID: urn:lsid:plantfossilnames.org:act:2000

Authors: E. M. Friis, P. R. Crane & K. R. Pedersen

Rank: species

Genus: Tanispermum E.M.Friis, P.R.Crane et K.R.Pedersen

Reference: Friis, E. M., Crane, P. R. & Pedersen, K. R. (2018): Tanispermum, a new genus of hemi-orthotropous to hemi-anatropous angiosperm seeds from the Early Cretaceous of eastern North America. – American Journal of Botany 105(8): 1369–1388.

Page of description: 1371

Illustrations or figures: figs 1–4

Name is type for

Types

Original diagnosis/description

Fruit one- or two-seeded, indehiscent, with a thin fruit wall. Isolated seeds single or in pairs, small, bitegmic, and exotestal. Seeds irregularly elliptical, either with a single flattened contact face from the other seed, or with evenly rounded faces. Hilum and micropyle widely spaced and seeds hemi-orthotropous to hemi-anatropous. One set of vascular bundles extends from the hilum to chalaza (raphe). Micropyle in the inner integument (tegmen) differentiated into a thickened plug, and in the outer integument seen as a small irregular, lobed opening. Testa formed from an outer layer of tall palisade-shaped sclerenchyma cells (exotesta) and an inner zone of thin-walled, loosely packed cells (mesotesta/endotesta), several cell layers deep. Anticlinal walls of the palisade cells unevenly thickened, thicker toward the inside resulting in an obconical cell lumen or thicker toward the outside resulting in a conical cell lumen. Exotestal cells with undulate outer and inner parts of anticlinal walls resulting in stellate-undulate facets and a jigsaw puzzle-like pattern on the seed surface and the inner surface of the exotesta. Tegmen thin except close to the micropyle where it is sclerified. Embryo small. Nutritive tissue cellular.
Fruit two-seeded. Seeds in pairs or singly. Seeds irregular elliptical with a single flattened contact face. Hilar scar circular to ovate. Anticlinal walls of exotesta cells very thick toward the outside, but thinning toward the inside, resulting in a conical cell lumen that tapers toward the outside.

Etymology

The species is named for the town of Hopewell, Virginia, United States, close to the Puddledock locality where the fossils were collected.

Stratigraphy

Cretaceous, Lower Cretaceous, Albian
Basal part of Subzone IIB, Potomac Group (early to middle Albian)

Locality

United States
Puddledock locality, former Tarmac Lone Star Industries (Vulcan Materials Co.) sand and gravel pit, located south of Richmond and east of the Appomattox River in Prince George County, Virginia (37°15′52′′N; 77°22′10′′W)