Rugaspermum minuta – a new species of the seed genus Rugaspermum from the Triassic of Nidpur, India

Abstract

This paper provides a description of a new species of Rugaspermum D.D.Pant & Basu, R. minuta Bhowmik & Parveen, from the Nidpur Triassic beds. The dispersed seeds were recovered aft er macerating large chunks of shale in hydrofl uoric acid. The structurally preserved compressed seed is platyspermic, orthotropus, and oval- to barrel-shaped with a short beak-like micropyle. The surfaces of the seeds are wrinkled and there is a wide lateral ridge running from the apex to the base on both the obverse and reverse sides. Upon maceration, the seed yielded 4 membranes: outer, inner, nucellar, and megaspore membranes. The outer cuticle of the integument is thick and nonstomatiferous, while the inner cuticle is thin and delicate. The nucellar membrane is granular. The megaspore membrane is tough and dark-stained, showing obscure polygonal cell outlines. The pollen chamber is disc-shaped, containing the Rugapites D.D.Pant & Basu type of pollen grains.