A Middle Devonian Callixylon (Archaeopteridales) from Ronquières, Belgium

in Review of Palaeobotany and Palynology (2012), 183

Diverse assemblages of Mid Devonian megaspores from Libya

in Review of Palaeobotany and Palynology (2011), 165

[en] A restudy of Devonian palynological assemblages of samples from the A1-69 borehole, drilled in the Ghadamis Basin, western Libya, North Africa has led to the discovery of numerous well-preserved ... [more ▼]

[en] A restudy of Devonian palynological assemblages of samples from the A1-69 borehole, drilled in the Ghadamis Basin, western Libya, North Africa has led to the discovery of numerous well-preserved megaspores amongst abundant miospores, rare acritarchs and rare chitinozoans. Thirteen samples from base to top, 1496 ft (456 m) up to 965 ft (294 m), contain the richest Devonian megaspore assemblages from northwestern Gondwana. The section is dated by a rich diverse miospore assemblage indicating the presence of the upper part of the AD pre-Lem Biozone up to the lower part of the TCo Oppel Zone, ranging from a latest Eifelian or earliest Givetian age up to a latest Givetian or an earliest Frasnian age. Seventeen megaspore taxa have been identified. Among them, two new species (Biharisporites lugardonii and Lagenicula milleri) and four new varieties (Corystisporites acutispinosus var. acutispinosus and var. bullatus, Heliotriletes longispinosus var. longispinosus and var. radiatus) are described. One new possible megaspore species is also described: Verruciretusispora labiosa sp. nov. One core sample (1293 ft, 394 m) contains several specimens of very large megaspores (ca. 1 mm), the largest known from Devonian localities (except for one specimen observed in the Givetian from Belgium). Among the 17 megaspore taxa from Libya, 6 are present on the Euramerican Continent. This observation is in accordance with previous palynological conclusions that favour the absence of palaeogeographic barriers between the Euramerican and Gondwanan continents that are suggested to be grouped together in a “Pre-Pangea” land mass. [less ▲]

Aberlemnia caledonica gen. et comb. nov., a new name for Cooksonia caledonica Edwards 1970.

in Review of Palaeobotany and Palynology (2010), 163

Preface: A tribute to Muriel Fairon-Demaret

in Review of Palaeobotany and Palynology (2006), 142(3-4), 61-61

Lectotypification of the Famennian pre-ovule Condrusia rumex Stockmans, 1948

in Review of Palaeobotany and Palynology (2006), 142(3-4), 161-164

Condrusia rumex Stockmans 1948 occurs in several localities of the Belgian Evieux Formation (late Famennian, Upper Devonian). It consists of a hastate organ borne at the tip of "slender, dichotomizing ... [more ▼]

Condrusia rumex Stockmans 1948 occurs in several localities of the Belgian Evieux Formation (late Famennian, Upper Devonian). It consists of a hastate organ borne at the tip of "slender, dichotomizing" axes. Various interpretations have been given to this intriguing structure, ranging from a spore-bearing organ to a fern prothallus but recent investigations consider Condrusia to be an ovulate structures produced by early seed plants. The genus Condrusia includes 3 species: C rumex Stockmans, C. minor Stockmans and C. brevis Petrosjan. C rumex was described by Stockmans in 1948, who provided a diagnosis and illustrations, but failed to designate a holotype. We are currently reinvestigating the genus and we here designate and illustrate a lectotype for the genus and species C. rumex. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

Lochkovian (earliest Devonian) miospores from the Solimoes Basin, northwestern Brazil

in Review of Palaeobotany and Palynology (2005), 133(1-2), 91-113

Eighteen core samples from PETROBRAS well 1-JD-1-AM (Jandiatuba area. Solimoes Basin. northwestern Brazil) have been studied for miospores. Fifty-three species are identified. This assemblage is ... [more ▼]

Eighteen core samples from PETROBRAS well 1-JD-1-AM (Jandiatuba area. Solimoes Basin. northwestern Brazil) have been studied for miospores. Fifty-three species are identified. This assemblage is tentatively correlated with the Z Phylozone of the BZ Oppel Zone (Steemans, P., 1989. Palynostratigraphie de l'Eodevonien dans l'ouest de l'Europe. Professional Paper. Memoires Explicatifs pour les Caries Geologiques and Mineralogiques de la Belgique, 27, pp. 453.), dated late Lochkovian, This is in accordance with previous age determinations based on chitinozoans and acritarchs. Numerous representatives of the miospore genus Dictyotriletes are observed. These enable recognition of the Dictyotriletes emsiensis morphon. an informal classification unit which includes Dictyotriletes granulatus, D. emsiensis, Dictyotriletes cf. subgranifer, specimens previously misassigned to D. subgranifer and some Dictyotriletes spp. provisionally left in open nomenclature. Since all intermediate forms from typical D. granulatus to typical D. emsiensis coexist. it is currently difficult to determine the base of "F" Interval Biozone in South America as originally defined in Western Europe. It is suggested. therefore. that the base of the "Ems" Biozone defined in Brazil cannot be correlated with the base of die "E" Biozone. Instead. it be included in an interval of uncertainty ranging from the European "Si" to "E" Biozones. Indeed. the underlying "NsZ" Biozone from South America, contains species not known below the "Si" Biozone. Here, the D. emsiensis morphon Assemblage Zone is erected, which may, be coeval with the "N" through "E" Biozones of Western Europe. The PISA palynoflora from the Parana Basin is also attributed to this new biozone. However, in the absence of species observed in the "BZ" Biozone (and also in the Solimoes Basin). the PISA assemblage could be somewhat older than that of well 1-JD-1-AM. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

Miospore assemblages from the Silurian-Devonian boundary, in borehole A1-61, Ghadamis Basin, Libya

in Review of Palaeobotany and Palynology (2002, April), 118(1-avr Sp. Iss. SI), 397-421

Well preserved and diversified miospore assemblages have been recorded from a relatively continuous sequence in borehole A1-61 which spans the Silurian-Devonian boundary in the northwestern part of the ... [more ▼]

Well preserved and diversified miospore assemblages have been recorded from a relatively continuous sequence in borehole A1-61 which spans the Silurian-Devonian boundary in the northwestern part of the Ghadamis Basin, Libya. The sequence is represented by early Devonian Lochkovian beds of the Tadrart Formation that transgress onto the Silurian Ludlow-Pridoli beds of the upper part of the 'Alternances Argilo-greseuses' Formation. The present work demonstrates a succession of miospore assemblages from closely sampled layers that have been stratigraphically dated as Ludlow-middle Pridoli and early Lochkovian by chitinozoans and acritarchs. Over 80 species of cryptospores and trilete spores have been identified. Modified detailed morphological interpretations are given. The miospore assemblages are correlated with miospore zonation schemes established for the type sequences of the Welsh Borderland, and those previously described from Libya. Early occurrences of some species as Streelispora newportensis on the western Gondwana plate, are put forward by comparison with the Old Red Sandstone continent. Phytogeographic and palaeobotanic implications based on these observations are discussed. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

Biometry and paleoenvironment of Retispora lepidophyta (Kedo) Playford 1976 and associated miospores in the latest Famennian nearshore marine facies, eastern Ardenne (Belgium)

in Review of Palaeobotany and Palynology (2002), 118(1-avr Sp. Iss. SI), 211-226

The size diameter of Retispora lepidophyta, a stratigraphically important miospore, is reexamined in greater detail than in previous studies using three sections of the latest Famennian nearshore marine ... [more ▼]

The size diameter of Retispora lepidophyta, a stratigraphically important miospore, is reexamined in greater detail than in previous studies using three sections of the latest Famennian nearshore marine facies of the eastern Ardenne. The evolutionary character of the size reduction with time is confirmed and is used for accurate correlations between the three sections. Cluster analyses (dendrograms) are performed on the percentages of a selection of miospore species from the two most complete sections and show a clear analogy in the lateral distribution of R. lepidophyta and Vallatisporites hystricosus, a species known elsewhere (West Virginia, USA) to belong to coastal 'downstream' near-swamp plant communities [Streel and Scheckler, Rev. Palaeobot. Palynol. 64 (1990) 315-324]. By comparison also with the West Virginia data, three Diducites species are believed to represent the 'coal' swamp vegetation. A decrease in the proportion of the Diducites species from the lower to the upper portion of the studied sections is observed. Using biometric analysis, high resolution correlation between these sections reveals a lateral shift of facies with time during the latest Famennian in the eastern Ardenne. Local synsedimentary block-faulting processes were probably responsible. (C) 2002 Elsevier Science B.V. All rights reserved. [less ▲]

Contributions to early land plant research (XIV IBC).

in Review of Palaeobotany and Palynology (2001), 116

Miospore Evolution from the Ordovician to the Silurian

in Review of Palaeobotany and Palynology (2000, December), 113(1-3), 189-196

The definition of the term cryptospore is amended to include only spores thought to be produced by embryophytes and to exclude all enigmatic palynomorphs. Cryptospores are included here in the miospore ... [more ▼]

The definition of the term cryptospore is amended to include only spores thought to be produced by embryophytes and to exclude all enigmatic palynomorphs. Cryptospores are included here in the miospore group.The oldest published assemblage of typical cryptospores is Llanvirn in age. The evolution of cryptospore assemblages is very slow from the Llanvirn to the early Llandovery. The Telychian and Sheinwoodian stages are periods of drastic impoverishment in cryptospore biodiversity, followed by an important modification in miospore assemblages. This step in the evolution of the vegetation is correlated with the rapid transgression of seas on the continent during the early Llandovery. On the other hand, the Hirnantian glaciation does not affect diversity of the miospore assemblages. [less ▲]