Monograph: Taxonomy and Classification of Some New Early Devonian Cryptospores from England

Early Devonian cryptospores are described from the Lower Old Red Sandstone (early Gedinnian) of Hereford and Worcester, and Shropshire, England. Two turmae (Nudialetes and Involucraletes), four suprasubturmae (Pseudopolyadi, Eupolyadi, Hilates and Ahilates), one subturma (Hilates), three infraturmae (Laevigati, Synorati and Apiculati), three genera (Acontotetras, Chelinohilates and Cymbohilates), eight species (Acontotetras inconspicuis, Artemopyra? scalariformis, Cymbohilates horridus, C. allenii, C. variabilis, C. disponerus, C. cymosus and Chelinohilates erraticus) and five varieties (Cymbohilates allenii vars allenii and magnus, C. variabilis vars variabilis, parvidecus and tenuis) are proposed as new. Cryptospores are divided into two major informal groups : eucryptospores and paracryptospores. Eucryptospore species have only one spore unit configuration and are either' permanent' tetrads, pseudodyads, dyads or monads. Most have laevigate or apiculate sculpture and are common and widespread in the study area. Paracryptospores have identical sculpture on variable, including abnormal, spore unit configurations (tetrads, triads, dyads and hilate monads). Only one paracryptospore species, Chelinohilates erraticus gen. et. sp. nov., is described herein. Paracryptospores may have a separate origin from eucryptospores and similar abnormal spore associations have been found in modern hybrid ferns. If the fossil variable spore units were produced by hybrid parents, and hybridization was a recurrent and common theme, then the impact upon patterns and rates of early land plant evolution would have been considerable.