Dj. Batten et Eb. Koppelhus, MORPHOLOGICAL REASSESSMENT OF SOME ZONATE AND CORONATE MEGASPORE GENERA OF MAINLY POSTPALEOZOIC AGE, Review of palaeobotany and palynology, 78(1-2), 1993, pp. 19-40
An analysis of Mesozoic and Tertiary megaspore assemblages from NW Eur
ope has shown that several zonate and coronate genera are not adequate
ly differentiated on the basis of their original diagnoses. A number o
f the species that have been described previously, and a few new forms
recently encountered, display characters that are attributable to mor
e than one genus. The genera considered are Auriculizonospora, Capilli
sporites, Dijkstraisporites, Flabellisporites, Henrisporites, Herbosis
porites, Membranisporites, Minerisporites, Pavlovisporites (a monotypi
c Permian form), Paxillitriletes, Sepisporites, Tenellisporites and Tr
iangulatisporites. A comparison of the morphology of all of the specie
s within this group that are known to us has enabled a reassessment of
the criteria on which they can be distinguished. As a result (1) Auri
culizonospora is reinstated as a genus that is distinct from Minerispo
rites, (2) the diagnoses of these two genera, Dijkstraisporites, Paxil
litriletes and Tenellisporites are emended, (3) Membranisporites is pl
aced in synonymy with Paxillitriletes, (4) six species are newly combi
ned with other genera, and (5) one is renamed. The nomenclatural chang
es are as follows: Dykstraisporites (al. Minerisporites) pterotus (Sin
gh, 1983) comb. nov., ?Flabellisporites (al. Tenellisporites) spinatus
(Peake, 1968) comb. nov., Minerisporites archangvillarae nom. nov. (n
ew name for Minerisporites elegans Archangelsky and Villar de Seoane,
1989, a junior homonym of M. elegans Li Wenben and Batten, 1987), Mine
risporites (al. Henrisporites) levis (Lachkar, 1979) comb. nov., Miner
isporites (al. Dijkstraisporites) psilites (Gunther and Hills, 1972) c
omb. nov., Paxilitriletes (al. Triletes) ales (Harris, 1935) comb. nov
., and Paxillitriletes (al. Triletes) samarus (Dijkstra, 1951) comb. n
ov. Although a few forms remain difficult to place because of their ''
intermediate'' character, it is now possible to refer the majority to
genera with greater confidence than hitherto. The chances of both taxo
nomic and nomenclatural confusion, and of biostratigraphic misinterpre
tation should, therefore, be reduced in the future. Most of the genera
are thought to have isoetalean origins but the three Triassic species
that have been referred to Triangulatisporites, and some of the other
species from this geological period may well be selaginellalean spore
s.