New findings of the seeds Allicospermum Harris (gymnosperms) from the Middle Jurassic of Angren, Uzbekistan

Three new species of the gymnosperm seed genus Allicospermum Harris - Allicospermum valentinae, Allicospermum uzbekistanicum and Allicospermum papillosum - are described from the Middle Jurassic of Angren, Uzbekistan (Middle Asia). The seeds, recovered by bulk maceration, differ in their sizes as well as in the fine structure of the megaspore membrane and of the outer epidermis of the seed coat. Allicospermum valentinae is notable for having a very thin outer cuticle of the seed coat and a thicker megaspore membrane characterized by vermicular sculpturing of the free surface of the foot layer. Allicospermum uzbekistanicum stands out in the larger seeds and in the megaspore membrane displaying unbranching thick sinuous bacula of the patterned layer arranged parallel to the foot layer. Allicospermum papillosum is peculiar in the development of solid papillae over much of the outer epidermis of the seed coat and of hair-like papillae near the seed apex, as well as in the presence of long resin bodies. The latter species possesses a Ginkgo type of stomata and has a megaspore membrane similar to that in Ginkgo biloba - both features rather suggesting a ginkgoalean affinity, which also cannot be ruled out for A. valentinae.