Jan Jansonius

PALAEOGENE FUNGAL SPORES AND FRUITING BODIES OF THE CANADIAN ARCTIC

Abstract In the Palaeogene deltaic sediments of the Mackenzie Delta region, fungal spores seem to be more resistant than other palynomorphs, occasionally constituting more than 50% of the assemblage. They have proved to be important and practical fossils for stratigraphic correlation. The Pesavis zone is named after the conidiospore Pesavis tagluensis. Evolutionary changes in fungi connected with the development of the angiosperms and local extinctions caused by alterations of the climate are reflected in the record. Relative abundances of major groups already identify gross stratigraphic intervals. Species are being identified and catalogued, so that their ranges can be determined. The variable morphology is illustrated on a plate; no new species are described.

Relationships among gymnospermous pollen

Abstract Close relationship of the pteridosperms to Ephedricae n. subdiv., Bennettitatae, and Pinatae is evident on the basis of pollen character. A pteridospermous complex evolving in multiple lines towards the gymnosperms is present in the Namurian through Stephanian time. Pollen of modern coniferalean groups is abundant in Jurassic sediments. Suggested relationships are based upon stratigraphic occurrence, morphology, and fructification data. Groups of morphologically similar form taxa show parallelism in separate lineages. Sacci and saccus-pendancy are common to both pteridosperms and Pinidae. A progression from trilete to monolete proximal marks, coupled to distal germination, seems to be the result of the development of bilateral symmetry and rearrangement of the tetrad. Seven lineages with precursors in the pteridospermous complex, and six major bursts of evolutionary activity are indicated (Appendix 2). The diagnoses of Illinites and Parasporites are supplemented. Schizopollis and others are noted for the first time in North America. The subclass Gnetidae is transferred to the class Pinatae on the basis of pollen character and stomata, necessitating Ephedricae n. subdiv. and Ephedratae n. class.

Systematics of the Chitinozoa

Abstract In the period 1930–1960 in total 15 genera were proposed in three families — Lagenochitinidae, Conochitinidae, and Desmochitinidae — of the order Chitinozoa Eisenack , 1931. Not including two withdrawn for technical reasons, up to August 1966 36 generic names had been validly proposed, three of which are considered to be synonyms. Four new genera have been announced informally at recent meetings of the C.I.M.P. subcommittee for Chitinozoa and five more new genera are discussed informally in this paper. Of these 45 genera, 42 are assigned here to five tribes. Overall size and morphology, structure of the prosome complex, aboral differentiations, and structure of the wall layers have been used as distinguishing criteria. The shorter stratigraphic ranges of the present genera indicate the soundness of the systematic nomenclature now developing.

A key to the genera of fossil angiosperm pollen

Abstract A utilitarian determination key, based on morphological characters, separates some eight hundred genera of dispersed fossil angiosperm pollen into small groups of similar structure or appearance. Its purpose is to aid the memory, as well as to provide an inventory of valid names for descriptive studies of new assemblages.